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  • ddc:550  (48)
  • Fisheries  (28)
  • 04.06. Seismology  (27)
  • Cell & Developmental Biology
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  • 1
    Publikationsdatum: 2022-04-04
    Beschreibung: Observations in polar regions show that sea ice deformations are often narrow linear features. These long bands of deformations are referred to as Linear Kinematic Features (LKFs). Viscous‐plastic sea ice models have the capability to simulate LKFs and more generally sea ice deformations. Moreover, viscous‐plastic models simulate a larger number and more refined LKFs as the spatial resolution is increased. Besides grid spacing, other aspects of a numerical implementation, such as the placement of velocities and the associated degrees of freedom, may impact the formation of simulated LKFs. To explore these effects this study compares numerical solutions of sea ice models with different velocity staggering in a benchmark problem. Discretizations based on A‐,B‐, and C‐grid systems on quadrilateral meshes have similar resolution properties as an approximation with an A‐grid staggering on triangular grids (with the same total number of vertices). CD‐grid approximations with a given grid spacing have properties, specifically the number and length of simulated LKFs, that are qualitatively similar to approximations on conventional Arakawa A‐grid, B‐grid, and C‐grid approaches with half the grid spacing or less, making the CD‐discretization more efficient with respect to grid resolution. One reason for this behavior is the fact that the CD‐grid approach has a higher number of degrees of freedom to discretize the velocity field. The higher effective resolution of the CD‐discretization makes it an attractive alternative to conventional discretizations.
    Beschreibung: Plain Language Summary: Sea ice in the Arctic and Antarctic Oceans plays an important role in the exchange of heat and freshwater between the atmosphere and the ocean and hence in the climate in general. Satellite observations of polar regions show that the ice drift sometimes produces long features that are either cracks (leads) and zones of thicker sea ice (pressure ridges). This phenomenon is called deformation. It is mathematically described by the non‐uniform way in which the ice moves. For numerical models of sea ice motion it is difficult to represent this deformation accurately. Details of the numerics may affect the way these models simulate leads and ridges, their number and length. Specifically, we find by comparing different numerical models, that the way the model variables are ordered on a computational grid to solve the mathematical equations of sea ice motion has an effect of how many deformation features can be represented on a grid with a given spacing between grid points. A new discretization (ordering of model variables) turns out to resolve more details of the approximated field than traditional methods.
    Beschreibung: Key Points: The placement of the sea ice velocity has a mayor influence on the number of simulated linear kinematic features (LKFs). The CD‐grid resolves twice as many LKFs compared to A, B, C‐grids. A, B, C‐grids on quadrilateral meshes resolve a similar number of LKFs as A‐grids on triangular meshes (with the same total number of nodes).
    Schlagwort(e): ddc:550 ; ddc:551.343
    Sprache: Englisch
    Materialart: doc-type:article
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Publikationsdatum: 2022-04-01
    Beschreibung: Porosity is one of the key properties of fluvial sediments. It is defined as the ratio of pore volume to total volume. In river science, porosity is often assumed to be spatially constant, which might be a gross simplification of reality. Ignoring the spatial variations in porosity can cause errors in morphological, ecological, hydrological, hydrogeological and sedimentological applications. Although detailed information about spatial porosity variations can be obtained from porosity measurements at field sites, such information has never been collected where these variations might be important. In this study, field porosity measurements were carried out to quantify the magnitude of the spatial porosity variation for four different sedimentological environments of a braided river: a confluence, a tributary delta, a braid bar and a secondary channel. A nuclear density gauge was used for the measurement of porosity. The nuclear density gauge proved to be a time‐saving and labour‐saving technique that produces accurate porosity values with a root mean square error of 0.03. The four sedimentological environments showed significant differences in porosity, with mean porosity being lower for confluence and bar than for delta and secondary channel. Semi‐variogram analysis showed the absence of any spatial correlation in porosity for distances beyond 4 m. This shows that distance cannot be used as a parameter for porosity extrapolation in a fluvial system unless the extrapolation distance is less than 4 m. At least eight measurements of porosity are required to obtain a reliable estimate of mean porosity in a sedimentary environment, i.e. with uncertainty 〈0.03. Although grain size characteristics were found to have a significant impact on porosity, the relationships between these parameters and porosity were not very strong in this study. The unique porosity dataset, presented in this article, provides a valuable source of information for researchers and river managers.
    Beschreibung: Deutsche Forschungsgemeinschaft
    Schlagwort(e): ddc:550
    Sprache: Englisch
    Materialart: doc-type:article
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Publikationsdatum: 2022-03-31
    Beschreibung: Mixed sand‐ and gravel‐bed rivers record erosion, transport, and fining signals in their bedload size distributions. Thus, grain‐size data are imperative for studying these processes. However, collecting hundreds to thousands of pebble measurements in steep and dynamic high‐mountain river settings remains challenging. Using the recently published digital grain‐sizing algorithm PebbleCounts, we were able to survey seven large (≥ 1,000 m2) channel cross‐sections and measure thousands to tens‐of‐thousands of grains per survey along a 100‐km stretch of the trunk stream of the Toro Basin in Northwest Argentina. The study region traverses a steep topographic and environmental gradient on the eastern margin of the Central Andean Plateau. Careful counting and validation allows us to identify measurement errors and constrain percentile uncertainties using large sample sizes. In the coarse ≥2.5 cm fraction of bedload, only the uppermost size percentiles (≥95th) vary significantly downstream, whereas the 50th and 84th percentiles show less variability. We note a relation between increases in these upper percentiles and along‐channel junctions with large, steep tributaries. This signal is strongly influenced by lithology and geologic structures, and mixed with local hillslope input. In steep catchments like the Toro Basin, we suggest nonlinear relationships between geomorphic metrics and grain size, whereby the steepest parts of the landscape exert primary control on the upper grain‐size percentiles. Thus, average or median metrics that do not apply weights or thresholds to steeper topography may be less predictive of grain‐size distributions in such settings.
    Beschreibung: Plain Language Summary: Rock fragments on hillsides are transported to rivers, eventually becoming pebbles, sand, and mud as they are carried downstream by flowing water. The initial size of the pebbles, the way the size changes downstream, and the overprinting of the sizes with new pebbles from other hills and tributaries all form a complex process that can be difficult to disentangle. Yet studying the size of the pebbles at a given stream location or in a sedimentary deposit can provide insights into the conditions of their transport in terms of local upstream patterns of erosion, tectonics, and climate. We show that just looking at the size of the large pebbles on a riverbed can be used to infer the sources of material, but, since there are fewer large pebbles, they require more measurements to quantify. This necessitates new methods for pebble measurement using modern image‐processing tools.
    Beschreibung: Key Points: Complex grain‐size distributions in dynamic mountain rivers can be computed via thousands of measurements from PebbleCounts. Many measurements allow robust estimation of higher percentiles and we observe the most significant changes in the ≥95th percentile. Downstream grain‐size variation is nonlinearly related to variations in topographic steepness and lithology.
    Beschreibung: Deutsches Zentrum für Luft‐ und Raumfahrt (DLR) http://dx.doi.org/10.13039/501100002946
    Beschreibung: Deutsche Forschungsgemeinschaft (DFG) http://dx.doi.org/10.13039/501100001659
    Beschreibung: Bundesministerium für Bildung und Forschung (BMBF) http://dx.doi.org/10.13039/501100002347
    Beschreibung: Brandenburger Staatsministerium für Wissenschaft, Forschung und Kultur (MWFK) http://dx.doi.org/10.13039/501100004581
    Beschreibung: https://zenodo.org/record/5089789
    Schlagwort(e): ddc:551.3 ; ddc:550
    Sprache: Englisch
    Materialart: doc-type:article
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Publikationsdatum: 2022-03-16
    Beschreibung: In this work, we assess ground shaking in the wider Zagreb area by computing simulated seismograms at regional distances. For the purposes of the simulations, we assemble the 3D velocity and density model and test its performance. First, we compare the low-frequency simulations obtained using deterministic method for both new 3D model and a simple 1D model. We then continue the performance test by computing the full broadband seismo- grams. To do that, we apply the hybrid technique in which the low frequency (f〈1 Hz) and high frequency (f=1–10 Hz) seismograms are obtained separately using deterministic and stochastic method, respectively, and then reconciled into a single time series. We apply this method to the MW=5.3 event and four smaller (3.0〈MW〈5.0) events that occurred in the studied region. We compare simulated data with the recorded seismograms and vali- date our results by calculating the goodness of fit score for peak ground velocity and shak- ing duration. Next, to improve the understanding of the strong ground motion in this area, we simulate seismic shaking scenarios for the 1880, MW = 6.2 earthquake. From computed low-frequency waveforms, we generate shakemaps and compare the ground-motion fea- tures of the two possible sources of this event, Kašina fault and North Medvednica fault. We conduct a preliminary study to determine which fault is a more probable source of the 1880 historic event by comparing the peak ground velocities and Arias intensity with the observed intensities.
    Beschreibung: Croatian Science Foundation under the Project No. IP-2020-02-3960 European Commission, H2020 Excel- lence Science [ChEESE (Grant No. 823844)]
    Beschreibung: Published
    Beschreibung: 167–192
    Beschreibung: 1T. Struttura della Terra
    Beschreibung: 6T. Studi di pericolosità sismica e da maremoto
    Beschreibung: JCR Journal
    Schlagwort(e): Numerical simulation ; 3D ground motion ; Earthquake ; Central Croatia ; Zagreb ; Seismic wave propagation ; 3D crustal model ; 04.06. Seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    Publikationsdatum: 2022-03-16
    Beschreibung: Data visualization, and to a lesser extent data sonification, are classic tools to the scientific community. However, these two approaches are very rarely combined, although they are highly complementary: our visual system is good at recognizing spatial patterns, whereas our auditory system is better tuned for temporal patterns. In this article, data representation methods are proposed that combine visualization, sonification, and spatial audio techniques, in order to optimize the user’s perception of spatial and temporal patterns in a single display, to increase the feeling of immersion, and to take advantage of multimodal integration mechanisms. Three seismic data sets are used to illustrate the methods, covering different physical phenomena, time scales, spatial distributions, and spatio-temporal dynamics. The methods are adapted to the specificities of each data set, and to the amount of information that the designer wants to display. This leads to further developments, namely the use of audification with two time scales, the switch from pure audification to time-modulated noise, and the switch from pure audification to sonic icons. First user feedback from live demonstrations indicates that the methods presented in this article seem to enhance the perception of spatio-temporal patterns, which is a key parameter to the understanding of seismically active systems, and a step towards apprehending the processes that drive this activity.
    Beschreibung: Published
    Beschreibung: 125–142
    Beschreibung: 7T. Variazioni delle caratteristiche crostali e "precursori"
    Beschreibung: JCR Journal
    Schlagwort(e): 04.06. Seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 6
    Publikationsdatum: 2022-03-29
    Beschreibung: A reanalysis is a physically consistent set of optimally merged simulated model states and historical observational data, using data assimilation. High computational costs for modeled processes and assimilation algorithms has led to Earth system specific reanalysis products for the atmosphere, the ocean and the land separately. Recent developments include the advanced uncertainty quantification and the generation of biogeochemical reanalysis for land and ocean. Here, we review atmospheric and oceanic reanalyzes, and more in detail biogeochemical ocean and terrestrial reanalyzes. In particular, we identify land surface, hydrologic and carbon cycle reanalyzes which are nowadays produced in targeted projects for very specific purposes. Although a future joint reanalysis of land surface, hydrologic, and carbon processes represents an analysis of important ecosystem variables, biotic ecosystem variables are assimilated only to a very limited extent. Continuous data sets of ecosystem variables are needed to explore biotic‐abiotic interactions and the response of ecosystems to global change. Based on the review of existing achievements, we identify five major steps required to develop terrestrial ecosystem reanalysis to deliver continuous data streams on ecosystem dynamics.
    Beschreibung: Plain Language Summary: A reanalysis is a unique set of continuous variables produced by optimally merging a numerical model and observed data. The data are merged with the model using available uncertainty estimates to generate the best possible estimate of the target variables. The framework for generating a reanalysis consists of the model, the data, and the model‐data‐fusion algorithm. The very specific requirements of reanalysis frameworks have led to the development of Earth‐compartment specific reanalysis for the atmosphere, the ocean and land. Here, we review atmospheric and oceanic reanalyzes, and in more detail biogeochemical ocean and terrestrial reanalyzes. In particular, we identify land surface, hydrologic, and carbon cycle reanalyzes which are nowadays produced in targeted projects for very specific purposes. Based on a review of existing achievements, we identify five major steps required to develop reanalysis for terrestrial ecosystem to shed more light on biotic and abiotic interactions. In the future, terrestrial ecosystem reanalysis will deliver continuous data streams on the state and the development of terrestrial ecosystems.
    Beschreibung: Key Points: Reanalyzes provide decades‐long model‐data‐driven harmonized and continuous data sets for new scientific discoveries. Novel global scale reanalyzes quantify the biogeochemical ocean cycle, terrestrial carbon cycle, land surface, and hydrologic processes. New observation technology and modeling capabilities allow in the near future production of advanced terrestrial ecosystem reanalysis.
    Beschreibung: European Union's Horizon 2020 research and innovation programme
    Beschreibung: Deutsche Forschungsgemeinschaft
    Beschreibung: U.S. Department of Energy
    Beschreibung: Emory University's Halle Institute for Global Research and the Halle Foundation Collaborative Research
    Beschreibung: NSF
    Beschreibung: NASA
    Beschreibung: Natural Environment Research Council
    Beschreibung: European Union'’s Horizon 2020 research and innovation programme
    Beschreibung: NSERC Discovery program, the Ocean Frontier Institute, and MEOPAR
    Beschreibung: Research Foundation Flanders (FWO)
    Beschreibung: Helmholtz Association
    Beschreibung: NASA Terrestrial Ecosystems
    Schlagwort(e): ddc:550
    Sprache: Englisch
    Materialart: doc-type:article
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    Publikationsdatum: 2022-03-25
    Beschreibung: Campi Flegrei caldera (Southern Italy) is one of the most hazardous volcanic complexes in the world since it is located inside the densely inhabited urban district of Naples-Pozzuoli. In the past, the caldera has produced devastating to moderate eruptions and periodically undergoes from strong to minor uplift episodes, named “bradyseism”, almost always accompanied by seismic swarms. Starting from 2005 Campi Flegrei has undergone an unrest crisis, characterized by ground uplift, localized gas emissions and seismicity, often occurring in seismic swarms. As a consequence, the monitoring activities have been progressively increasing, producing a huge amount of data, difficult to manage and match. GIS (Geographical Information System) represents a potent tool to manage great quantity of data, coming from different disciplines. In this study, we show two GIS technology applications to the seismic catalogue of Campi Flegrei. In the first one, a high-quality dataset is extracted from the GeoDatabase addressed to seismological studies that require high precision earthquake locations. In the second application, GIS are used to extract, visualize and analyse the typical seismic swarms of Campi Flegrei. Moreover, density and seismic moment distribution maps were generated for these swarms. In the last application, the GIS allow to highlight a clear variation in the temporal trend of the seismic swarms at Campi Flegrei.
    Beschreibung: This study has benefited from funding provided by the Italian Presidenza del Consiglio dei Ministri – Dipartimento della Protezione Civile.
    Beschreibung: Published
    Beschreibung: 131-144
    Beschreibung: 4V. Processi pre-eruttivi
    Beschreibung: 6SR VULCANI – Servizi e ricerca per la società
    Beschreibung: 1IT. Reti di monitoraggio e sorveglianza
    Beschreibung: N/A or not JCR
    Schlagwort(e): Campi Flegrei ; Seismic swams ; Seismic network ; GIS ; 04.06. Seismology ; 04.08. Volcanology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    Publikationsdatum: 2021-11-29
    Beschreibung: The geological evolution of the western Mediterranean exhibits complicated interactions between orogenic processes and widespread extensional tectonics. The region is located in a convergent plate margin separating Africa and Europe, and consists of marine basins – the Alboran Sea, the Algerian- Provençal Basin, the Valencia trough, the Ligurian Sea and the Tyrrhenian Sea- which formed as back-arc basins since the Oligocene. In most reconstructions, it has been stressed that back-arc extension led to drifting of continental blocks and to large-scale block rotations. The opening of the Ligurian Sea. is in fact the result of counterclockwise rotation of Corsica and Sardinia. From the point of view of seismicity, the south western Alps and northern part of the Ligurian basin are subject to frequent earthquakes of low to moderate magnitudes. However significantly destructive events are known to have occurred in the past (e.g. 1564 and 1887). Apart from these rare large events, regional studies agree in concluding that the important local microseismicity appears to be poorly focused (e.g., COURBOULEX et alii, 2007) and that, if some tectonic lines are documented onland (COURBOULEX et alii, 2001), the active structures at sea remain unknown. It is therefore an essential prerequisite to gain better insight into the deep seismogenic structures along the North Ligurian margin and even farther offshore, in the identified oceanic domain. The fact that some of these structures can undergo ruptures of Mw~6.5, such as the 1887 event (BAKUN & SCOTTI, 2006), suggests that, at least to some extent, instrumental insufficiencies in the detection and location of microseismicity is a limit to identify active faults that have not experienced large instrumented ruptures to date. The irregular coverage provided by regional seismic networks produces a bias in the recording of local seismicity. Permanent stations are naturally limited to land areas and fail to properly constrain seismicity offshore. Taking into consideration the peculiarities of regional dynamics (low strain rates, rare large events and a regular seismic activity limited to small events with M 〈 3-4), even onshore seismicity is insufficiently covered by permanent networks and requires dense temporary instrumenting by mobile stations. Considering the potential threat of strong offshore earthquakes, it is of first importance to characterize faults that are prone to rupture in order to quantify associated seismic and tsunami hazards. Assuming some weak seismicity exists along these faults and remains undetected by onland networks, some marine stations are necessary to address instrumental remoteness and help delineate active structures. Moreover, since the velocity models used for locations are obtained by inverting seismic data and the reliability of their locations depend, in turn, from the quality of the velocity model used for their hypocentral parameters, the constraints on the seismic path provided by a more dense seismic network may contribute to a more accurate reference model. In this study, we profited from the recent developments in sea bottom seismic instrumentation to deploy OBSs above the zones of the North Ligurian to perform seismic shots and obtain the distribution of seismic velocities with 3D active tomography. We also took the opportunity of the long term (6 months) OBSs reduced array to decrease both the detection threshold and recording distances so as to obtain more complete catalogs and better localisations.
    Beschreibung: Published
    Beschreibung: 789-791
    Beschreibung: 1T. Struttura della Terra
    Beschreibung: N/A or not JCR
    Schlagwort(e): 04.01. Earth Interior ; 04.06. Seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    Publikationsdatum: 2021-11-30
    Beschreibung: Historical seismic catalogs report that the Gargano Promontory (southern Italy) was affected in the past by earthquakes with medium to high estimated magnitude. From the instrumental seismicity, it can be identified that the most energetic Apulian sequence occurred in 1995 with a main shock of MW = 5.2 followed by about 200 aftershocks with a maximum magnitude of 3.7. The most energetic earthquakes of the past are attributed to right-lateral strike-slip faults, while there is evidence that the present-day seismicity occur on thrust or thrust-strike faults. In this article, we show a detailed study on focal mechanisms and stress field obtained by micro-seismicity recorded from April 2013 until the present time in the Gargano Promontory and surrounding regions. Seismic waveforms are collected from the OTRIONS Seismic Network (OSN), from the Italian National Seismic Network (RSN), and integrated with data from the Italian National Accelerometric Network (RAN) in order to provide a robust dataset of earthquake localizations and focal mechanisms. The effect of uncertainties of the velocity model on fault plane solutions (FPS) has been also evaluated indicating the robustness of the results. The computed stress field indicates a deep compressive faulting with maximum horizontal compressive stress, SHmax, trending NW-SE. The seismicity pattern analysis indicates that the whole crust is seismically involved up to a depth of 40 km and indicates the presence of a low-angle seismogenic surface trending SW-NE and dipping SE-NW, similar to the Gargano–Dubrovnik lineament. Shallower events, along the eastern sector of the Mattinata Fault (MF), are W-E dextral strike-slip fault. Therefore, we hypothesized that the seismicity is locally facilitated by preexisting multidirectional fractures, confirmed by the heterogeneity of focal mechanisms, and explained by the different reactivation processes in opposite directions over the time, involving the Mattinata shear zone.
    Beschreibung: Published
    Beschreibung: 589332
    Beschreibung: 4T. Sismicità dell'Italia
    Beschreibung: JCR Journal
    Schlagwort(e): Gargano promontory ; OTRIONS local seismic network ; focal mechanisms ; stress field ; microseismicity ; mattinata fault ; gargano-dubrovnik lineament ; 04.06. Seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 10
    Publikationsdatum: 2021-11-12
    Beschreibung: In this paper we describe the results of an experimental implementation of the recent guidelines issued by the Italian regulatory body for monitoring hydrocarbon production activities. In particular, we report about the pilot study on seismic, deformation, and pore pressure monitoring of the Mirandola hydrocarbon cultivation facility in Northern Italy. This site hosts the Cavone oil field that was speculated of possibly influencing the 2012 ML 5.8 Mirandola earthquake source. According to the guidelines, the monitoring center should analyse geophysical measurements related to seismicity, crustal deformation and pore pressure in quasi real-time (within 24–48 h). A traffic light system would then be used to regulate underground operations in case of detecting significant earthquakes (i.e., events with size and location included in critical ranges). For these 2-year period of guidelines experimentation, we analysed all different kinds of available data, and we tested the existence of possible relationship between their temporal trends. Despite the short time window and the scarce quantity of data collected, we performed the required analysis and extracted as much meaningful and statistically reliable information from the data. We discuss here the most important observations drawn from the monitoring results, and highlight the lessons learned by describing practical issues and limitations that we have encountered in carrying out the tasks as defined in the guidelines. Our main goal is to contribute to the discussion about how to better monitor the geophysical impact of this kind of anthropogenic activity. We point out the importance of a wider seismic network but, mostly, of borehole sensors to improve microseismic detection capabilities. Moreover, the lack of an assessment of background seismicity in an unperturbed situation -due to long life extraction activities- makes it difficult to get a proper picture of natural background seismic activity, which would be instead an essential reference information for a tectonically-active regions, such as Northern Italy.
    Beschreibung: “Convenzione tra il comune di San Possidonio e l’Istituto Nazionale di Geofisica e Vulcanologia -I.N.G.V.- per l’attuazione del monitoraggio nella concessione di coltivazione idrocarburi “Mirandola” finalizzata alla messa in opera di attività di monitoraggio di sperimentazione degli indirizzi e linee guida per i monitoraggi ILG ed assunzione funzioni di Struttura Preposta al Monitoraggio di cui all’art. 6 del Protocollo Operativo”
    Beschreibung: Published
    Beschreibung: 685300
    Beschreibung: 3SR TERREMOTI - Attività dei Centri
    Beschreibung: JCR Journal
    Schlagwort(e): Italian guidelines for monitoring industrial activities ; induced seismicity ; pore pressure monitoring ; deformation monitoring ; seismic monitoring ; 04.06. Seismology ; 05.09. Miscellaneous ; 04.02. Exploration geophysics ; 04.03. Geodesy
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 11
    Publikationsdatum: 2021-12-15
    Beschreibung: The analysis of how an earthquake is felt was addressed with the data provided by citizens through a website dedicated to the perception of earthquakes in Italy (Data and Resources). The analysis focused on the perception of earthquakes by observers inside both parked and moving cars. These situations were compared with outdoor ones. The felt percentage of each situation was quantified for epicentral distance ranges and European Macroseismic Scale (EMS) degree. One of the main findings was the greatest sensitivity to shaking for people inside parked cars due to resonance phenomena of the automobile–observer system. The distribution of the intensity of perception in the car was analyzed as a function of the hypocentral distance and the magnitude of the earthquake. It was possible to define the attenuation trends of these intensities. The comparison of these trends with those of the equations for estimation of response spectral ordinates allowed us to have an evaluation of the frequency values of the seismic waves that caused the vibrations felt, which were found to agree with the typical frequencies of the car–observer system, as highlighted by independent studies. The results of this analysis show the possibility to include the perception of the earthquake inside a parked and moving car among the diagnostics used in the definition of macroseismic intensity degree of the EMS.
    Beschreibung: Published
    Beschreibung: 2028–2035
    Beschreibung: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica
    Beschreibung: 5SR TERREMOTI - Convenzioni derivanti dall'Accordo Quadro decennale INGV-DPC
    Beschreibung: JCR Journal
    Schlagwort(e): macroseismics ; questionnaires ; 04.06. Seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 12
    Publikationsdatum: 2021-12-13
    Beschreibung: Strategies for disaster risk reduction in volcanic areas are mostly driven by multidisciplinary analyses, which offer effective and complementary information on complex geomorphological and volcano-tectonic environments. For example, quantification of the offset at active faults and fissures is of paramount importance to shed light on the kinematics of zones prone to deformation and/or seismic activity. This provides key information for the assessment of seismic hazard, but also for the identification of conditions that may favor magma uprising and opening of eruptive fissures. Here we present the results of a study encompassing detailed geological, structural and seismological observations focusing on part of the NE Rift at Etna volcano (Italy). The area is situated at an elevation ranging between 2700 and 1900 m a.s.l. where harsh meteorological conditions and difficult logistics render classical field work a troublesome issue. In order to bypass these difficulties, high-resolution (2.8 cm) UAV survey has been recently completed. The survey highlights the presence of 250 extension fractures, 20 normal fault segments, and 54 eruptive fissures. The study allows us to quantify the kinematics at extensional fractures and normal faults, obtaining an extension rate of 1.9 cm/yr for the last 406 yr. With a total of 432 structural data collected by UAV along with SfM photogrammetry, this work also demonstrates the suitability of the application of such surveys for the monitoring of hazardous zone.
    Beschreibung: Published
    Beschreibung: online (vEGU21)
    Beschreibung: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica
    Schlagwort(e): Etna ; stress and strain field ; active faults ; NE Rift ; volcano ; kinematics ; UAV survey ; multidisciplinary analysis ; 04.08. Volcanology ; 04.06. Seismology ; 04.07. Tectonophysics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: Conference paper
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  • 13
    Publikationsdatum: 2021-12-15
    Beschreibung: We investigated the seismic fault structure and the rupture characteristics of the MW 6.6, 2 May 2020, Cretan Passage earthquake through tsunami data inverse modelling. Our results suggest a shallow crustal event with a reverse mechanism within the accretionary wedge rather than on the Hellenic Arc subduction interface. The study identifies two possible ruptures: a steeply sloping reverse splay fault and a back-thrust rupture dipping south, with a more prominent dip angle.
    Beschreibung: We present a source solution for the tsunami generated by the Mw 6.6 earthquake that occurred on 2 May 2020, about 80 km offshore south of Crete, in the Cretan Passage, on the shallow portion of the Hellenic Arc subduction zone (HASZ). The tide gauges recorded this local tsunami on the southern coast of Crete and Kasos island. We used Crete tsunami observations to constrain the geometry and orientation of the causative fault, the rupture mechanism, and the slip amount. We first modelled an ensemble of synthetic tsunami waveforms at the tide gauge locations, produced for a range of earthquake parameter values as constrained by some of the available moment tensor solutions. We allow for both a splay and a back-thrust fault, corresponding to the two nodal planes of the moment tensor solution. We then measured the misfit between the synthetic and the Ierapetra observed marigram for each source parameter set. Our results identify the shallow, steeply dipping back-thrust fault as the one producing the lowest misfit to the tsunami data. However, a rupture on a lower angle fault, possibly a splay fault, with a sinistral component due to the oblique convergence on this segment of the HASZ, cannot be completely ruled out. This earthquake reminds us that the uncertainty regarding potential earthquake mechanisms at a specific location remains quite significant. In this case, for example, it is not possible to anticipate if the next event will be one occurring on the subduction interface, on a splay fault, or on a back-thrust, which seems the most likely for the event under investigation. This circumstance bears important consequences because back-thrust and splay faults might enhance the tsunamigenic potential with respect to the subduction interface due to their steeper dip. Then, these results are relevant for tsunami forecasting in the framework of both the long-term hazard assessment and the early warning systems.
    Beschreibung: Published
    Beschreibung: 3713–3730
    Beschreibung: 8T. Sismologia in tempo reale e Early Warning Sismico e da Tsunami
    Beschreibung: JCR Journal
    Schlagwort(e): Tsunami, Mediterranean, Early Warning ; 04.06. Seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 14
    Publikationsdatum: 2021-12-16
    Beschreibung: A new analysis of high-resolution multibeam and seismic reflection data, collected during several oceanographic expeditions starting from 1999, allowed us to compile an updated morphotectonic map of the North Anatolian Fault below the Sea of Marmara. We reconstructed kinematics and geometries of individual fault segments, active at the time scale of 10 ka, an interval which includes several earthquake cycles, taking as stratigraphic marker the base of the latest marine transgression. Given the high deformation rates relative to sediment supply, most active tectonic structures have a morphological expression at the seafloor, even in presence of composite fault geometries and/or overprinting due to mass-wasting or turbidite deposits. In the frame of the right-lateral strike-slip domain characterizing the North Anatolian fault system, three types of deformation are observed: almost pure strike-slip faults, oriented mainly E–W; NE/SW-aligned axes of transpressive structures; NW/SE-oriented trans-tensional depressions. Fault segmentation occurs at different scales, but main segments develop alongthree major right-lateral oversteps, which delimit main fault branches, from east to west: (i) the transtensive Cinarcik segment; (ii) the Central (East and West) segments; and (iii) the westernmost Tekirdag segment. A quantitative morphometric analysis of the shallow deformation patterns observed by seafloor morphology maps and high-resolution seismic reflection profiles along the entire basin allowed to determine nature and cumulative lengths of individual fault segments. These data were used as inputs for empirical relationships, to estimate maximum expected Moment Magnitudes, obtaining values in the range of 6.8–7.4 for the Central, and 6.9–7.1 for the Cinarcik and Tekirdag segments, respectively. We discuss these findings considering analyses of historical catalogues and available paleoseismological studies for the Sea of Marmara regionto formulate reliable seismic hazard scenarios.
    Beschreibung: Published
    Beschreibung: 29–44
    Beschreibung: 6T. Studi di pericolosità sismica e da maremoto
    Beschreibung: N/A or not JCR
    Schlagwort(e): North Anatolian fault · ; Sea of Marmara ; Earthquakes ; Active fault segments ; Marine geophysics ; Seismic hazard ; 04.06. Seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 15
    Publikationsdatum: 2021-12-22
    Beschreibung: The Western Ionian Sea is characterised by an active and diffuse seismicity, directly related to the convergence of the European and African Plates and by gravitational sinking and rollback of the oceanic lithosphere. In this area, the location of earthquakes is characterised by considerable uncertainties due to large azimuthal gaps, resulting in notable location errors. This problem was partially overcome with the use of data recorded by NEMO-SN1 seafloor observatory (October 2002 - February 2003; June 2012 - May 2013). We relocated 1130 crustal and sub-crustal earthquakes using land network and NEMO-SN1 data. As most events occurred on Mt. Etna, we focused on 358 earthquakes in the offshore area and near the coasts of Sicily and Calabria. The use of the combined land-marine networks has improved the earthquake locations in terms of azimuthal GAP, as well as in horizontal and vertical errors. The comparison between locations performed with and without NEMO-SN1 data shows that differences in latitude, longitude and depths are more evident in the Western Ionian Sea and in the coast of Sicily, where values of the differences over 5 km correspond to structural heterogeneities. The increased number of seismic stations deployed on land from 2003 to 2012 did not influence the location of events occurring offshore, where NEMO-SN1 continued to be the distinctive tool in the location process. Moreover, the new 73 focal mechanisms computed with P-wave polarities from NEMO-SN1 and land stations are in agreement with the regional structural model, showing a prevalent normal, normal/oblique, and strike-slip kinematics. The similarity of two new focal solutions with the mechanisms of the main shock and aftershock of the 1990 earthquake demonstrates that the seismic structures are still active and potentially dangerous. The P-wave travel time residual analysis confirms the activity along the main structural alignments. A single point of observation in the Ionian Sea can significantly improve the quality of locations, giving an opportunity to focus on the seismogenic structures responsible for the occurrence of medium-to-high magnitude earthquakes.
    Beschreibung: Published
    Beschreibung: Se655
    Beschreibung: 1T. Struttura della Terra
    Beschreibung: JCR Journal
    Schlagwort(e): Earthquake location ; Focal mechanisms ; Tectonic and volcanic structures ; NEMO-SN1 seafloor observatory ; Ionian Sea ; 04. Solid Earth ; 04.06. Seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 16
    Publikationsdatum: 2021-12-22
    Beschreibung: Collapse of buildings, large-scale destruction and temporary abandonment of an area documented in archaeological reports provide evidence for a major earthquake in Segesta in north-western Sicily. This, and possibly a cluster of other earthquakes as recently well-documented at Selinunte (south-western), can be derived from archaeological data. These earthquakes are not included in the Italian seismic catalogues, but can be used to set constraints on the seismic risk of this area. Although western Sicily is a low seismic moment release region, characterized by sparse, low-moderate magnitude earthquakes, the occurrence of strong earthquakes in the past would instead suggest the investigated area as having a high seismic potential. The present study improves the knowledge of past earthquakes of this area, thus contributing to a more reliable characterization of seismic hazard.
    Beschreibung: Submitted
    Beschreibung: 4T. Sismicità dell'Italia
    Beschreibung: JCR Journal
    Schlagwort(e): historical earthquake ; archaeoseismology, ; buildings collapse ; western Sicily ; Segesta ; 04.06. Seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: manuscript
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  • 17
    Publikationsdatum: 2021-12-22
    Beschreibung: The comparison between crustal stress and surface strain azimuthal patterns has provided new insights into several complex tectonic settings worldwide. Here, we performed such a comparison for Egypt taking into account updated datasets of seismological and geodetic observations. In north-eastern Egypt, the stress field shows a fan-shaped azimuthal pattern with a WNW–ESE orientation on the Cairo region, which progressively rotated to NW–SE along the Gulf of Aqaba. The stress field shows a prevailing normal faulting regime, however, along the Sinai/Arabia plate boundary it coexists with a strike–slip faulting one (σ1 ≅ σ2 〉 σ3), while on the Gulf of Suez, it is characterized by crustal extension occurring on near-orthogonal directions (σ1 〉 σ2 ≅ σ3). On the Nile Delta, the maximum horizontal stress (SHmax) pattern shows scattered orientations, while on the Aswan region, it has a WNW–ESE strike with pure strike–slip features. The strain-rate field shows the largest values along the Red Sea and the Sinai/Arabia plate boundary. Crustal stretching (up to 40 nanostrain/yr) occurs on these areas with WSW–ENE and NE–SW orientations, while crustal contraction occurs on northern Nile Delta (10 nanostrain/yr) and offshore (~35 nanostrain/yr) with E–W and N–S orientations, respectively. The comparison between stress and strain orientations over the investigated area reveals that both patterns are near-parallel and driven by the same large-scale tectonic processes.
    Beschreibung: This research was partially funded by the Programa Operativo FEDER Andalucía 2014-2020—A call made by the University of Jaén 2018.
    Beschreibung: Published
    Beschreibung: 1398
    Beschreibung: 2T. Deformazione crostale attiva
    Beschreibung: JCR Journal
    Schlagwort(e): strain ; stress ; GNSS ; Egypt ; 04.03. Geodesy ; 04. Solid Earth ; 04.06. Seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 18
    Publikationsdatum: 2021-12-23
    Beschreibung: A comparative analysis of geodetic versus seismic moment-rate estimations makes it possible to distinguish between seismic and aseismic deformation, define the style of deformation, and also to reveal potential seismic gaps. This analysis has been performed for Egypt where the present-day tectonics and seismicity result from the long-lasting interaction between the Nubian, Eurasian, and Arabian plates. The data used comprises all available geological and tectonic information, an updated Poissonian earthquake catalog (2200 B.C.–2020 A.D.) including historical and instrumental datasets, a focal-mechanism solutions catalog (1951–2019), and crustal geodetic strains from Global Navigation Satellite System (GNSS) data. The studied region was divided into ten (EG-01 to EG-10) crustal seismic sources based mainly on seismicity, focal mechanisms, and geodetic strain characteristics. The delimited seismic sources cover the Gulf of Aqaba–Dead Sea Transform Fault system, the Gulf of Suez–Red Sea Rift, besides some potential seismic active regions along the Nile River and its delta. For each seismic source, the estimation of seismic and geodetic moment-rates has been performed. Although the obtained results cannot be considered to be definitive, among the delimited sources, four of them (EG-05, EG-06, EG-08, and EG-10) are characterized by low seismic-geodetic moment-rate ratios (〈20%), reflecting a prevailing aseismic behavior. Intermediate moment-rate ratios (from 20% to 60%) have been obtained in four additional zones (EG-01, EG-04, EG-07, and EG-09), evidencing how the seismicity accounts for a minor to a moderate fraction of the total deformational budget. In the other two sources (EG-02 and EG-03), high seismic-geodetic moment-rates ratios (〉60%) have been observed, reflecting a fully seismic deformation
    Beschreibung: This research has been partially funded in the frame of the Programa Operativo FEDER Andalucía 2014–2020-call made by the University of Jaén, 2018.
    Beschreibung: Published
    Beschreibung: 7836
    Beschreibung: 2T. Deformazione crostale attiva
    Beschreibung: JCR Journal
    Schlagwort(e): Seismicity ; GNSS ; Strain ; seismic hazard ; Egypt ; 04. Solid Earth ; 04.03. Geodesy ; 04.06. Seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 19
    Publikationsdatum: 2021-12-23
    Beschreibung: Infrasonic signals investigation plays a fundamental role for both volcano monitoring purpose and the study of the explosion dynamics. Proper and reliable detection of weak signals is a critical issue in active volcano monitoring. In particular, in volcanic acoustics, it has direct consequences in pinpointing the real number of generated events (amplitude transients), especially when they exhibit low amplitude, are close in time to each other, and/or multiple sources exist. To accomplish this task, several algorithms have been proposed in literature; in particular, to overcome limitations of classical approaches such as short-time average/long-time average and cross-correlation detector, in this paper a subspace-based detection technique has been implemented. Results obtained by applying subspace detector on real infrasound data highlight that this method allows sensitive detection of lower energy events. This method is based on a projection of a sliding window of signal buffer onto a signal subspace that spans a collection of reference signals, representing similar waveforms from a particular infrasound source. A critical point is related to subspace design. Here, an empirical procedure has been applied to build the signal subspace from a set of reference waveforms (templates). In addition, in order to determine detectors parameters, such as subspace dimension and detection threshold, even in presence of overlapped noise such as infrasonic tremor, a statistical analysis of noise has been carried out. Finally, the subspace detector reliability and performance, have been assessed by performing a comparison among subspace approach, cross correlation detector and short-time average/long-time average detector. The obtained confusion matrix and extrapolated performance indices have demonstrated the potentiality, the advantages and drawbacks of the subspace method in tracking volcanic activity producing infrasound events. This method revealed to be a good compromise in detecting low-energy and very close in time events recorded during Strombolian activity
    Beschreibung: Published
    Beschreibung: 579923
    Beschreibung: 5V. Processi eruttivi e post-eruttivi
    Beschreibung: JCR Journal
    Schlagwort(e): infrasound signal ; trigger algorithm ; infrasound volcano monitoring ; strombolian activity ; etna volcano ; infrasonic tremor ; subspace detector ; infrasound events ; solid earth ; 04.08. Volcanology ; 04.06. Seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 20
    Publikationsdatum: 2021-12-22
    Beschreibung: The earthquake of May 24th, 2008, occurred in the municipality of Quetame (Colombia), is a recent event detected by the RSNC and the World Seismological Network, which reported their seismological parameters: epicenter, depth, magnitude, scalar seismic moment and focal mechanism, among others. Based on the damages and effects caused, INGEOMINAS (Colombian Geological Survey) evaluated the macroseismic field, preparing the map of intensities with data in various populations of the departments of Cundinamarca, Tolima and Meta, mainly. Based on this macroseismic information, in this work some macroseismic analysis methods are applied to obtain the corresponding focal parameters. The results show strong correlations or similarities between instrumental and macroseismic parameters. Instrumentally reported: Epicenter 4.4°N and 73.81°W; h=14.7 km, 5.9 Mw, 5.9 Ms, 5.6 mb, 5.7 ML; M0=7.95*1024 dynes-cm. While macroseismically it was obtained: Epicenter 4.34°N and 73.86°W; 5.94 Mw, 5.5 Ms, 5.6±0.2 mb, 5.63 ML; hn=12.1 km, hl=2.23 km; E=4.57*1020 erg, M0=9.14*1024 dynes-cm; the parameters of the dimensions of the seismic focus and the seismotectonic deformation expressed by the seismic flow of the rock mass were also determined. The applied procedures show the character of complementarity between instrumental and macroseismic data.
    Beschreibung: Published
    Beschreibung: 163-184
    Beschreibung: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica
    Beschreibung: JCR Journal
    Schlagwort(e): earthquakes ; focal parameters ; macroseismic ; 04.06. Seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 21
    Publikationsdatum: 2021-11-17
    Beschreibung: The geographic distribution of earthquake effects quantified in terms of macroseismic intensities, the so-called macroseismic field, provides basic information for several applications including source characterization of pre-instrumental earthquakes and risk analysis. Macroseismic fields of past earthquakes as inferred from historical documentation may present spatial gaps, due to the incompleteness of the available information. We present a probabilistic approach aimed at integrating incomplete intensity distributions by considering the Bayesian combination of estimates provided by intensity prediction equations (IPEs) and data documented at nearby localities, accounting for the relevant uncertainties and the discrete and ordinal nature of intensity values. The performance of the proposed methodology is tested at 28 Italian localities with long and rich seismic histories and for two well-known strong earthquakes (i.e., 1980 southern Italy and 2009 central Italy events). A possible application of the approach is also illustrated relative to a 16th-century earthquake in the northern Apennines.
    Beschreibung: Published
    Beschreibung: 2299–2311
    Beschreibung: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica
    Beschreibung: JCR Journal
    Schlagwort(e): 04.06. Seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 22
    Publikationsdatum: 2021-12-01
    Beschreibung: Ischia is a densely inhabited and touristic volcanic island located in the northern sector of the Gulf of Naples (Italy). In 2017, the Mw 3.9 Casamicciola earthquake occurred after more than one century of seismic quiescence characterized only by minor seismicity, which followed a century with three destructive earthquakes (in 1828, 1881, and 1883). These events, despite their moderate magnitude (Mw 〈 5.5), lead to dreadful effects on buildings and population. However, an integrated catalogue systematically covering historical and instrumental seismicity of Ischia has been still lacking since many years. Here, we review and systematically re-analyse all the available data on the historical and instrumental seismicity, to build an integrated earthquake catalogue for Ischia with a robust characterization of existing uncertainties. Supported by new or updated macroseismic datasets, we significantly enriched existing catalogues, as the Italian Parametric Earthquake Catalogue (CPTI15) that, with this analysis, passed from 12 to 57 earthquakes with macroseismic parametrization. We also extended back by 6 years the coverage of the instrumental catalogue, homogenizing the estimated seismic parameters. The obtained catalogue will not only represent a solid base for future local hazard quantifications, but also it provides the unique opportunity of characterizing the evolution of the Ischia seismicity over centuries. To this end, we analyse the spatial, temporal, and magnitude distributions of Ischia seismicity, revealing for example that, also in the present long-lasting period of volcanic quiescence, is significantly non-stationary and characterized by a b-value larger than 1.
    Beschreibung: This work benefited of the agreement between Istituto Nazionale di Geofisica e Vulcanologia and the Italian Presidenza del Consiglio dei Ministri, Dipartimento della Protezione Civile (DPC).
    Beschreibung: Published
    Beschreibung: 629736
    Beschreibung: 4T. Sismicità dell'Italia
    Beschreibung: 6SR VULCANI – Servizi e ricerca per la società
    Beschreibung: 1IT. Reti di monitoraggio e sorveglianza
    Beschreibung: 4IT. Banche dati
    Beschreibung: JCR Journal
    Schlagwort(e): Ischia island ; Volcano seismicity ; Seismic catalogue ; Completeness analysis ; Ensemble modelling ; Frequency size distribution ; Poisson process ; 04.06. Seismology ; 04.08. Volcanology ; 05.02. Data dissemination ; 05.04. Instrumentation and techniques of general interest
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 23
    Publikationsdatum: 2021-12-24
    Beschreibung: This article has been accepted for publication in Geophysical Journal International ©: The Authors 2021. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. Uploaded in accordance with the publisher's self-archiving policy.
    Beschreibung: Ambient-noise records from the AlpArray network are used to measure Rayleigh wave phase velocities between more than 150,000 station pairs. From these, azimuthally anisotropic phase-velocity maps are obtained by applying the Eikonal tomography method. Several synthetic tests are shown to study the bias in the Ψ2 anisotropy. There are two main groups of bias, the first one caused by interference between refracted/reflected waves and the appearance of secondary wavefronts that affect the phase travel-time measurements. This bias can be reduced if the amplitude field can be estimated correctly. Another source of error is related to the incomplete reconstruction of the travel-time field that is only sparsely sampled due to the receiver locations. Both types of bias scale with the magnitude of the velocity heterogeneities. Most affected by the spurious Ψ2 anisotropy are areas inside and at the border of low-velocity zones. In the isotropic velocity distribution, most of the bias cancels out if the azimuthal coverage is good. Despite the lack of resolution in many parts of the surveyed area, we identify a number of anisotropic structures that are robust: in the central Alps, we find a layered anisotropic structure, arc-parallel at midcrustal depths and arc-perpendicular in the lower crust. In contrast, in the eastern Alps, the pattern is more consistently E-W oriented which we relate to the eastward extrusion. The northern Alpine forleand exhibits a preferential anisotropic orientation that is similar to SKS observations in the lowermost crust and uppermost mantle.
    Beschreibung: German Science Foundation (SPP-2017, Project Ha 2403/21-1); Swiss National Science Foundation SINERGIA Project CRSII2-154434/1 (Swiss-AlpArray); Progetto Pianeta Dinamico, finanziamento MUR-INGV, Task S2 – 2021
    Beschreibung: Published
    Beschreibung: 151–170
    Beschreibung: 1T. Struttura della Terra
    Beschreibung: JCR Journal
    Schlagwort(e): Seismic anisotropy ; Seismic interferometry ; Seismic tomography ; Wave propagation ; Continental tectonics: compressional ; 04.01. Earth Interior ; 04.06. Seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 24
    Publikationsdatum: 2021-12-14
    Beschreibung: We present results from a joint inversion of new seismic and recently compiled gravity data to constrain the structure of a prominent geophysical anomaly in the European Alps: the Ivrea Geophysical Body (IGB). We investigate the IGB structure along the West-East oriented Val Sesia profile at higher resolution than previous studies. We deployed 10 broadband seismic stations at 5 km spacing for 27 months, producing a new database of ∼1000 high-quality seismic receiver functions (RFs). The compiled gravity data yields 1 gravity point every 1–2 km along the profile. We set up an inversion scheme, in which RFs and gravity anomalies jointly constrain the shape and the physical properties of the IGB. We model the IGB’s top surface as a single density and shear-wave velocity discontinuity, whose geometry is defined by four, spatially variable nodes between far-field constraints. An iterative algorithm was implemented to efficiently explore the model space, directing the search toward better fitting areas. For each new candidate model, we use the velocity-model structures for both ray-tracing and observed-RFs migration, and for computation and migration of synthetic RFs: the two migrated images are then compared via cross-correlation. Similarly, forward gravity modeling for a 2D density distribution is implemented. The joint inversion performance is the product of the seismic and gravity misfits. The inversion results show the IGB protruding at shallow depths with a horizontal width of ∼30 km in the western part of the profile. Its shallowest segment reaches either 3–7 or 1–3 km depth below sea-level. The latter location fits better the outcropping lower crustal rocks at the western edge of the Ivrea-Verbano Zone. A prominent, steep eastward-deepening feature near the middle of the profile, coincident with the Pogallo Fault Zone, is interpreted as inherited crustal thickness variation. The found density and velocity contrasts of the IGB agree with physical properties of the main rock units observed in the field. Finally, by frequency-dependent analysis of RFs, we constrain the sharpness of the shallowest portion of the IGB velocity discontinuity as a vertical gradient of thickness between 0.8 km and 0.4 km.
    Beschreibung: The Swiss National Science Foundation (SNF) supported this research (grant numbers PP00P2_157627 and PP00P2_187199 of project OROG3NY), as well as the Grant Agency of the Czech Republic (No. 21-25710). The project CzechGeo/EPOS No. LM2015079 of the MEYS funded the MOBNET station pool.
    Beschreibung: Published
    Beschreibung: 671412
    Beschreibung: 1T. Struttura della Terra
    Beschreibung: JCR Journal
    Schlagwort(e): joint inversion ; seismic receiver functions ; gravity anomalies ; Ivrea Geophysical Body ; Ivrea-Verbano Zone ; continental crust ; intra-crustal structure ; 04.01. Earth Interior ; 04.06. Seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 25
    Publikationsdatum: 2021-12-13
    Beschreibung: The present paper describes the process of moving from a research study of most common vulnerable non-structural elements, to deliver solutions, tools and guidelines to improve understanding of and responsiveness to community concerns about seismic risk and non-structural elements. The observed damage to non-structural elements following recent earthquakes in Italy, Portugal and Iceland, were used for designing communication tools under the KnowRISK EU project for multi-stakeholders (students, business and citizens): the Practical Guide, the Students Short Guide, the KnowRISK Portfolio of Solutions, the Move, Protect and Secure video, the augmented reality apps, the maquettes, the students notebooks, videos, board games and hands-on tools. The philosophy behind these deliverables is that some risks, once identified, can be eliminated or reduced by informing people and suggesting preventive or emergency measures. These tools are devoted to improving the seismic performance of non-structural elements and to reduce the associated economic losses, loss of functionality, and potential threats to life safety. The rationale behind the selection of the information that people need to know for converting knowledge to more safety is discussed and a description of the transference of the findings of research to communication solutions is presented. The tools were planned following the engagement-model in risk communication to ensure that needs of communities and selected stakeholders were acknowledged, and that recipients are addressed in a way that appeals to them. Different media and communication channels such as print, television, online, face-to face communication and interviews were used for risk communication.
    Beschreibung: This study was co-financed by the European Commission’s Humanitarian Aid and Civil Protection (Grant agreement ECHO/SUB/2015/718655/PREV28).
    Beschreibung: Published
    Beschreibung: SE322
    Beschreibung: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica
    Beschreibung: JCR Journal
    Schlagwort(e): Seismic risk ; seismic damage ; non-structural damage ; preventative measures ; risk awareness ; 04.06. Seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 26
    Publikationsdatum: 2021-12-15
    Beschreibung: This article has been accepted for publication in Geophysical Journal International ©: The Authors 2022. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. Uploaded in accordance with the publisher's self-archiving policy.
    Beschreibung: To understand the seismotectonics and the seismic hazard of the study sector of the Northern Apennines (Italy), one of the most important earthquakes of magnitude Mw = 6.5 which struck the Lunigiana and Garfagnana areas (Tuscany) on 7 September 1920 should be studied. Given the early instrumental epoch of the event, neither geometric and kinematic information on the fault-source nor its fault-plane solution were available. Both areas were candidates for hosting the source fault and there was uncertainty between a normal fault with Apenninic direction or an anti-Apenninic strike-slip. We retrieved 11 focal parameters (including the fault-plane solution) of the 1920 earthquake. Only macroseismic intensity information (from 499 inhabited centres) through the KF-NGA inversion technique was used. This technique uses a Kinematic model of the earthquake source and speeds up the calculation by a Genetic Algorithm with Niching. The result is a pure dip-slip focal solution. The intrinsic ambiguities of the KF-NGA method (±180° on the rake angle; choice of the fault plane between the two nodal planes) were solved with field and seismotectonic evidence. The earthquake was generated by a normal fault (rake angle = 265° ± 8°) with an Apennine direction (114° ± 5°) and dipping 38° ± 6° towards SW. The likely candidate for hosting the source-fault in 1920 is the Compione-Comano fault that borders the NE edge of the Lunigiana graben. The KF-NGA algorithm proved to be invaluable for studying the kinematics of early instrumental earthquakes and allowed us to uniquely individuate, for the first time ever, the seismogenic source of the 1920 earthquake. Our findings have implications in hazard computation and seismotectonic contexts.
    Beschreibung: Published
    Beschreibung: 1465–1477
    Beschreibung: 4T. Sismicità dell'Italia
    Beschreibung: JCR Journal
    Schlagwort(e): Inverse theory ; Body waves ; Earthquake source observations ; Seismicity and tectonics ; Dynamics: seismotectonics ; Fractures, faults, and high strain deformation zones ; 04.06. Seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 27
    Publikationsdatum: 2022-01-13
    Beschreibung: Istituto Nazionale di Geofisica e Vulcanologia
    Beschreibung: Published
    Beschreibung: 2T. Deformazione crostale attiva
    Beschreibung: 4T. Sismicità dell'Italia
    Beschreibung: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica
    Beschreibung: 6T. Studi di pericolosità sismica e da maremoto
    Beschreibung: 4IT. Banche dati
    Schlagwort(e): Seismogenic Source ; Active Fault ; Active Fault System ; 04.04. Geology ; 04.06. Seismology ; 04.07. Tectonophysics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: web product
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  • 28
    Publikationsdatum: 2021-11-26
    Beschreibung: Seismicity-based earthquake forecasting models have been primarily studied and developed over the past twenty years. These models mainly rely on seismicity catalogs as their data source and provide forecasts in time, space, and magnitude in a quantifiable manner. In this study, we presented a technique to better determine future earthquakes in space based on spatially smoothed seismicity. The improvement’s main objective is to use foreshock and aftershock events together with their mainshocks. Time-independent earthquake forecast models are often developed using declustered catalogs, where smaller-magnitude events regarding their mainshocks are removed from the catalog. Declustered catalogs are required in the probabilistic seismic hazard analysis (PSHA) to hold the Poisson assumption that the events are independent in time and space. However, as highlighted and presented by many recent studies, removing such events from seismic catalogs may lead to underestimating seismicity rates and, consequently, the final seismic hazard in terms of ground shaking. Our study also demonstrated that considering the complete catalog may improve future earthquakes’ spatial forecast. To do so, we adopted two different smoothed seismicity methods: (1) the fixed smoothing method, which uses spatially uniform smoothing parameters, and (2) the adaptive smoothing method, which relates an individual smoothing distance for each earthquake. The smoothed seismicity models are constructed by using the global earthquake catalog with Mw ≥ 5.5 events. We reported progress on comparing smoothed seismicity models developed by calculating and evaluating the joint log-likelihoods. Our resulting forecast shows a significant information gain concerning both fixed and adaptive smoothing model forecasts. Our findings indicate that complete catalogs are a notable feature for increasing the spatial variation skill of seismicity forecasts.
    Beschreibung: Published
    Beschreibung: 10899
    Beschreibung: 6T. Studi di pericolosità sismica e da maremoto
    Beschreibung: JCR Journal
    Schlagwort(e): seismic hazard ; Smoothed Seismicity Approach ; global seismic catalog ; aftershocks ; 04.06. Seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 29
    Publikationsdatum: 2021-11-25
    Beschreibung: Ambient noise polarizes inside fault zones, yet the spatial and temporal resolution of polarized noise on gas-bearing fluids migrating through stressed volcanic systems is unknown. Here we show that high polarization marks a transfer structure connecting the deforming centre of the caldera to open hydrothermal vents and extensional caldera-bounding faults during periods of low seismic release at Campi Flegrei caldera (Southern Italy). Fluids pressurize the Campi Flegrei hydrothermal system, migrate, and increase stress before earthquakes. The loss of polarization (depolarization) of the transfer and extensional structures maps pressurized fluids, detecting fluid migrations after seismic sequences. After recent intense seismicity (December 2019-April 2020), the transfer structure appears sealed while fluids stored in the east caldera have moved further east. Our findings show that depolarized noise has the potential to monitor fluid migrations and earthquakes at stressed volcanoes quasi-instantaneously and with minimum processing.
    Beschreibung: Published
    Beschreibung: 6656
    Beschreibung: 4V. Processi pre-eruttivi
    Beschreibung: JCR Journal
    Schlagwort(e): Campi Flegrei ; seismic noise ; polarization ; fluid migration ; 04.06. Seismology ; 04.08. Volcanology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 30
    Publikationsdatum: 2021-12-23
    Beschreibung: The SW Iberian margin is one of the most seismogenic and tsunamigenic areas in W-Europe, where large historical and instrumental destructive events occurred. To evaluate the sensitivity of the tsunami impact on the coast of SW Iberia and NW Morocco to the fault geometry and slip distribution for local earthquakes, we carried out a set of tsunami simulations considering some of the main known active crustal faults in the region: the Gorringe Bank (GBF), Marquês de Pombal (MPF), Horseshoe (HF), North Coral Patch (NCPF) and South Coral Patch (SCPF) thrust faults, and the Lineament South strike-slip fault. We started by considering for all of them relatively simple planar faults featuring with uniform slip distribution; we then used a more complex 3D fault geometry for the faults constrained with a large 2D multichannel seismic dataset (MPF, HF, NCPF, and SCPF); and finally, we used various heterogeneous slip distributions for the HF. Our results show that using more complex 3D fault geometries and slip distributions, the peak wave height at the coastline can double compared to simpler tsunami source scenarios from planar fault geometries. Existing tsunami hazard models in the region use homogeneous slip distributions on planar faults as initial conditions for tsunami simulations and therefore underestimate tsunami hazard. Complex 3D fault geometries and non-uniform slip distribution should be considered in future tsunami hazard updates. The tsunami simulations also support the finding that submarine canyons attenuate the wave height reaching the coastline, while submarine ridges and shallow shelves have the opposite effect.
    Beschreibung: Published
    Beschreibung: e2021JB022127
    Beschreibung: 2T. Deformazione crostale attiva
    Beschreibung: 6T. Studi di pericolosità sismica e da maremoto
    Beschreibung: 2TR. Ricostruzione e modellazione della struttura crostale
    Beschreibung: 2IT. Laboratori analitici e sperimentali
    Beschreibung: JCR Journal
    Schlagwort(e): tsunami ; earthquake ; complex fault geometry ; heterogeneous slip distribution ; tsunami numerical modeling ; seismic and tsunami hazard ; 04.04. Geology ; 04.06. Seismology ; 05.08. Risk
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 31
    Publikationsdatum: 2021-12-14
    Beschreibung: The Italian earthquake waveform data are collected here in a dataset suited for machine learning analysis (ML) applications. The dataset consists of nearly 1.2 million three-component (3C) waveform traces from about 50 000 earthquakes and more than 130 000 noise 3C waveform traces, for a total of about 43 000 h of data and an average of 21 3C traces provided per event. The earthquake list is based on the Italian Seismic Bulletin (http://terremoti.ingv.it/bsi, last access: 15 February 2020​​​​​​​) of the Istituto Nazionale di Geofisica e Vulcanologia between January 2005 and January 2020, and it includes events in the magnitude range between 0.0 and 6.5. The waveform data have been recorded primarily by the Italian National Seismic Network (network code IV) and include both weak- (HH, EH channels) and strong-motion (HN channels) recordings. All the waveform traces have a length of 120 s, are sampled at 100 Hz, and are provided both in counts and ground motion physical units after deconvolution of the instrument transfer functions. The waveform dataset is accompanied by metadata consisting of more than 100 parameters providing comprehensive information on the earthquake source, the recording stations, the trace features, and other derived quantities. This rich set of metadata allows the users to target the data selection for their own purposes. Much of these metadata can be used as labels in ML analysis or for other studies. The dataset, assembled in HDF5 format, is available at http://doi.org/10.13127/instance (Michelini et al., 2021).
    Beschreibung: Published
    Beschreibung: 5509–5544
    Beschreibung: 4T. Sismicità dell'Italia
    Beschreibung: JCR Journal
    Schlagwort(e): 04.06. Seismology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 32
    Publikationsdatum: 2022-12-08
    Beschreibung: Einer der bekanntesten Forscher in Ungarn war der 1919 verstorbene Lóránd Eötvös. Dieser Artikel wurde zum Gedenken erstellt. Viele wissenschaftliche Theorien und Erfindungen sind mit seinem Namen verbunden. Beispiele sind der Eötvös-Effekt, das Torsionspendel oder die Vermutung der „fünften Kraft“.
    Beschreibung: DFG, SUB Göttingen
    Beschreibung: research
    Schlagwort(e): ddc:550 ; Kontinentalwanderung ; Wegener ; polare Abstoßungskraft ; Milanković
    Sprache: Deutsch
    Materialart: doc-type:article , publishedVersion
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  • 33
    Publikationsdatum: 2022-10-26
    Beschreibung: © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Kourantidou, M., Hoagland, P., Dale, A., & Bailey, M. Equitable allocations in northern fisheries: bridging the divide for Labrador Inuit. Frontiers in Marine Science, 8, (2021): 590213, https://doi.org/10.3389/fmars.2021.590213.
    Beschreibung: Canada has undertaken commitments to recognize the rights of Indigenous Peoples in fisheries through policies and agreements, including Integrated Fishery Management Plans, the Reconciliation Strategy, and Land Claim Agreements (LCAs). In addition to recognizing rights, these commitments were intended to respect geographic adjacency principles, to enhance the economic viability of Indigenous communities, and to be reflective of community dependence on marine resources. We examined the determinants of quota allocations in commercial fisheries involving Nunatsiavut, Northern Labrador, the first self-governing region for the Inuit peoples in Canada. It has been argued that current fishery allocations for Nunatsiavut Inuit have not satisfied federal commitments to recognize Indigenous rights. Indicators that measure equity in commercial allocations for the turbot or Greenland halibut (Reinhardtius hippoglossoides) and northern shrimp (Pandalus borealis) fisheries were identified and assessed. In these two cases, historical allocations continue to predominate for allocations based upon equity or other social or economic considerations. We illustrate equity-enhancing changes in the quota distribution under scenarios of different levels of inequality aversion, and we make qualitative assessments of the effects of these allocations to Nunatsiavut for socioeconomic welfare. This approach could benefit fisheries governance in Northern Labrador, where federal commitments to equity objectives continue to be endorsed but have not yet been integrated fully into quota allocations.
    Beschreibung: This research was undertaken with funding from the Canada First Research Excellence Fund through the Ocean Frontier Institute (MK and MB) and the Johnson Endowment of the Woods Hole Oceanographic Institution’s (WHOI) Marine Policy Center (PH).
    Schlagwort(e): Fisheries ; Allocations ; Equity ; Indigenous rights ; Access
    Repository-Name: Woods Hole Open Access Server
    Materialart: Article
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  • 34
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    Publikationsdatum: 2022-09-26
    Beschreibung: Die Instrumente an Bord des am 9. Februar 2020 gestarteten Solar Orbiters beobachten die Sonne und messen die Teilchen und elektromagnetischen Felder im Sonnenwind. Dieser Artikel gibt eine Übersicht über die Mission und fasst eine Auswahl der ersten Ergebnisse zusammen. Solar Orbiter wird in den kommenden Jahren durch seine detaillierten Beobachtungen der Sonne und Messungen des Sonnenwindes das Feld der Weltraumgeophysik maßgeblich mitbestimmen.
    Beschreibung: DFG, SUB Göttingen
    Beschreibung: research
    Schlagwort(e): ddc:550
    Sprache: Deutsch
    Materialart: doc-type:article
    Format: 10
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  • 35
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    Selbstverlag | Jena
    Publikationsdatum: 2022-07-12
    Beschreibung: Die Erdbeben in Thüringen und angrenzenden Gebieten aus den Jahren von 841 bis 2020 werden zusammengestellt. Damit wird für dieses Gebiet ein schneller Überblick über die Seismizität ermöglicht. In dieser, nunmehr letzten Ausgabe, wurden die bekannten historischen seismischen Ereignisse mit Rücksicht auf eine neue Quelle auf einen neuen Stand gebracht. Die Verteilung der Erdbeben, so zeigt sich, folgt ausgewählten geologischen Störungen. Sie rechtfertigt die Aufteilung des Untersuchungsgebietes in vier seismische Regionen.
    Beschreibung: report
    Schlagwort(e): ddc:550 ; ddc:551.22
    Sprache: Deutsch
    Materialart: doc-type:book
    Format: 38
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  • 36
    Publikationsdatum: 2022-09-20
    Beschreibung: Die 1902 von Emil Wiechert errichtete Göttinger Erdbebenstation GTT ist heute noch voll funktionsfähig und wird seit 2005 vom Verein Wiechert'sche Erdbebenwarte Göttingen betreut und von vielen Besuchern bestaunt. Die Registrierung einer 3 km entfernten Bombensprengung zeigt eindrucksvoll die große Übereinstimmung der Seismogramme des 17t-Pendels von GTT und dem benachbarten STS-2-Breitbandseismometer der Station GTTG.
    Beschreibung: DFG, SUB Göttingen
    Beschreibung: research
    Schlagwort(e): ddc:550
    Sprache: Deutsch
    Materialart: doc-type:article
    Format: 6
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  • 37
    Publikationsdatum: 2022-09-20
    Beschreibung: Aus Anlass des 100. Jahrestages der Gründung der Deutschen Geophysikalischen Gesellschaft im Jahre 1922 in Leipzig erschien im Verlag Edition am Gutenbergplatz Leipzig das Taschenbuch „Wiechert, Mintrop & Co. – Die 24 Gründungsväter der Deutschen Geophysikalischen Gesellschaft“ von Franz Jacobs und Michael Börngen (siehe gleichlautenden Archivbeitrag in DGG-Mitteilungen 1/2019: 36–37). Die DGG-Präsidentin Heidrun Kopp hat darin das Geleitwort geschrieben. Das Buch kann über den Buchhandel unter ISBN 978-3-95922-107-8 bestellt werden. Der folgende Artikel über den Aachener Meteorologen Peter Polis ist ein leicht erweitertes Kapitel aus diesem Buch.
    Beschreibung: DFG, SUB Göttingen
    Beschreibung: research
    Schlagwort(e): ddc:550
    Sprache: Deutsch
    Materialart: doc-type:article
    Format: 6
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  • 38
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    In:  aqdchief@seafdec.org.ph | http://aquaticcommons.org/id/eprint/18569 | 2002 | 2015-11-15 16:06:30 | 18569 | Southeast Asian Fisheries Development Center, Aquaculture Department
    Publikationsdatum: 2022-08-02
    Beschreibung: This paper summarizes the results of the experiments on the induced breeding and larval rearing of milkfish (Chanos chanos) during the 1979 season. Milkfish larvae could be reared successfully without the use of trochophore larvae of oysters as feed during the first few days. In order to induce the ovulation of wild adult milkfish a higher dose of human chorionic gonadotropin hormone is required.
    Schlagwort(e): Fisheries ; Chanos chanos ; ISEW ; Philippines ; marine environment ; Brood stocks ; Fish culture ; Fish larvae ; Food organisms ; Induced breeding ; Larval development ; Sex hormones
    Repository-Name: AquaDocs
    Materialart: article
    Format: application/pdf
    Format: application/pdf
    Format: 1-3
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  • 39
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    Unbekannt
    In:  library@seafdec.org.ph | http://aquaticcommons.org/id/eprint/20100 | 17342 | 2016-02-24 22:18:26 | 20100 | Southeast Asian Fisheries Development Center, Aquaculture Department
    Publikationsdatum: 2022-08-02
    Beschreibung: An outline is given of aquaculture and fisheries in Asia, providing information of use to students whose work can influence laws, rules, policy and regulations on aquaculture and fisheries, with the view in mind to sustainable aquaculture. In this issue, the following countries are examined: China, Indonesia, and Bangladesh.
    Schlagwort(e): Aquaculture ; Fisheries ; Fishery management ; Aquaculture development ; Aquaculture regulations ; Marine aquaculture ; Freshwater aquaculture ; Fishery industry ; Asia ; Bangladesh ; China
    Repository-Name: AquaDocs
    Materialart: article
    Format: application/pdf
    Format: application/pdf
    Format: 7-8
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  • 40
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    In:  library@seafdec.org.ph | http://aquaticcommons.org/id/eprint/20067 | 2002 | 2016-03-04 15:16:24 | 20067 | Southeast Asian Fisheries Development Center, Aquaculture Department
    Publikationsdatum: 2022-08-02
    Schlagwort(e): Fisheries ; Aquaculture ; Vietnam ; Sri Lanka ; Sri Lanka ; Vietnam ; brackishwater environment ; freshwater environment ; marine environment ; Aquaculture ; Aquaculture techniques ; Brackishwater aquaculture ; Feed ; Fish culture ; Fish diseases ; Fisheries ; Fishery data ; Food organisms ; Freshwater aquaculture ; Marine aquaculture ; Marine fisheries ; Mollusc culture ; Pond culture ; Seaweed culture ; Shrimp culture
    Repository-Name: AquaDocs
    Materialart: article
    Format: application/pdf
    Format: application/pdf
    Format: pp.9-10, 27
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  • 41
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    Unbekannt
    In:  library@seafdec.org.ph | http://aquaticcommons.org/id/eprint/20055 | 2002 | 2016-03-03 11:33:32 | 20055 | Southeast Asian Fisheries Development Center, Aquaculture Department
    Publikationsdatum: 2022-08-02
    Schlagwort(e): Fisheries ; Aquaculture ; Asia ; Cambodia ; India ; Asia ; Cambodia ; India ; Myanmar ; Myanmar ; brackishwater environment ; freshwater environment ; marine environment ; Aquaculture ; Aquaculture development ; Aquaculture economics ; Aquaculture techniques ; Brackishwater aquaculture ; Catching methods ; Culture effects ; Environmental impact ; Fish culture ; Fisheries ; Fishery development ; Fishery resources ; Fishery statistics ; Freshwater aquaculture ; Marine aquaculture ; Shrimp culture ; Sustainability ; Trade
    Repository-Name: AquaDocs
    Materialart: article
    Format: application/pdf
    Format: application/pdf
    Format: pp.9-10, 29
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  • 42
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26291 | 23782 | 2019-04-08 09:42:05 | 26291 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publikationsdatum: 2022-08-02
    Schlagwort(e): Fisheries ; Pollution ; Indonesia ; Heavy metals ; Chemical pollution ; Pollution monitoring
    Repository-Name: AquaDocs
    Materialart: book_section
    Format: application/pdf
    Format: application/pdf
    Format: 10-19
    Format: 10
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  • 43
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26293 | 23782 | 2019-03-22 03:49:21 | 26293 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publikationsdatum: 2022-08-02
    Schlagwort(e): Fisheries ; Myanmar ; Heavy metals ; Cadmium ; Lead ; Mercury ; Biological sampling ; Fish ; Fishery products ; Seafood
    Repository-Name: AquaDocs
    Materialart: book_section
    Format: application/pdf
    Format: application/pdf
    Format: 38-46
    Format: 9
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  • 44
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    Secretariat, Southeast Asian Fisheries Development Center | Bangkok, Thailand
    In:  http://aquaticcommons.org/id/eprint/26259 | 2002 | 2019-03-01 05:56:06 | 26259 | Southeast Asian Fisheries Development Center, Secretariat
    Publikationsdatum: 2022-08-02
    Beschreibung: Round scad exploration by purse seine in the waters of western Philippines was conducted from April 22 to May 7, 1998 for a period of five (5) fishing days with a total catch of 7.3 tons and an average of 1.5 tons per setting. Dominant species caught were Decapterus spp. having 70.09% of the total catch, followed by Selar spp. at 12.66% and Rastrelliger spp. 10.70%. Among the Decapterus spp. caught, D. macrosoma attained the highest total catch composition by species having 68.81% followed by D. kurroides and D.russelli with 0.31% and 1.14% respectively. The round scad fishery stock was composed mainly of juvenile fish (less than 13 cm) and Age group II (13 cm to 14 cm). Few large round scad at Age group IV and V (20 cm to 28 cm) stayed at the fishery. Other fishes caught were: Auxis rochei (0.85%), A. thazard (0.12%), Caranx spp. (0.45%), Emmilichthys nitidus (0.58%), Euthynnus affinis (0.42%), Leiognathus ruconius (0.58%), Loligo sp. (0.31%), Megalaspis cordyla (0.09%), Rastrelliger spp. (10.70%), Sardinella longiceps (0.03%), Scomberoides lysan (0.24%), Selar spp. (12.66%), Sphyraena spp. (0.90%), Thunnus albacares (0.96%) and others (1.02%). Tuna and tuna like fishes such as yellowfin tuna, eastern little tuna, bullet tuna, frigate tuna and oceanic squid are distributed in the upper latitudes of the survey area. On the other hand, round scads, big-eyed scads and Indian mackerels are dominantly present in the lower latitudes of the survey area.
    Schlagwort(e): Fisheries ; Exploratory fishing ; Purse seining ; Age composition ; Catch composition ; Fishery surveys ; Carangid fisheries ; South China Sea ; Philippines ; Rastrelliger ; Decapterus
    Repository-Name: AquaDocs
    Materialart: book_section
    Format: application/pdf
    Format: application/pdf
    Format: 49-64
    Format: 16
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  • 45
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    Training Department, Southeast Asian Fisheries Development Center | Samut Prakarn, Thailand
    In:  http://aquaticcommons.org/id/eprint/26215 | 17342 | 2019-02-08 06:25:54 | 26215 | Southeast Asian Fisheries Development Center, Training Department
    Publikationsdatum: 2022-08-02
    Beschreibung: Presented in this paper is the status of the fishery industry in Brunei Darussalam. Specifically, it discussed the following topics: fishery management strategies, zonation scheme, licencing, the use of poisons and explosives, the minimum cod-end mesh size for trawlers, closed areas, enhancement of fishing grounds, and the enforcement activities.
    Schlagwort(e): Fisheries ; Fishery resources ; Fishery management ; Fisheries ; Ecological zonation ; Licensing ; Fish poisoning ; Catching methods ; Illegal fishing ; Explosive fishing ; Fishing gear ; Season regulations ; Fishing grounds
    Repository-Name: AquaDocs
    Materialart: book_section
    Format: application/pdf
    Format: application/pdf
    Format: 34-40
    Format: 7
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  • 46
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26295 | 23782 | 2019-03-22 08:39:12 | 26295 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publikationsdatum: 2022-08-02
    Schlagwort(e): Fisheries ; Thailand ; Cadmium ; Lead ; Mercury ; Biological sampling ; Fish ; Fishery products ; Seafood
    Repository-Name: AquaDocs
    Materialart: book_section
    Format: application/pdf
    Format: application/pdf
    Format: 53-58
    Format: 6
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  • 47
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26292 | 23782 | 2019-03-22 03:43:09 | 26292 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publikationsdatum: 2022-08-02
    Schlagwort(e): Fisheries ; Malaysia ; Cadmium ; Lead ; Mercury ; Biological sampling ; Fish ; Fishery products ; Seafood
    Repository-Name: AquaDocs
    Materialart: book_section
    Format: application/pdf
    Format: application/pdf
    Format: 20-37
    Format: 18
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  • 48
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    Secretariat, Southeast Asian Fisheries Development Center | Bangkok, Thailand
    In:  http://aquaticcommons.org/id/eprint/26258 | 2002 | 2019-03-01 06:00:19 | 26258 | Southeast Asian Fisheries Development Center, Secretariat
    Publikationsdatum: 2022-08-02
    Beschreibung: An exploratory tuna longline fishing survey was conducted using the research and training vessels of the Southeast Asian Fisheries Development Center, the 1,178 GT MV SEAFDEC and the Bureau of Fisheries and Aquatic Resources, the 165 GT MV MAYA-MAYA in the South China Sea Waters, West of the Philippines from April to May, 1998. A total of 3,796 hooks was set in sixteen (16) fishing stations. There were no tuna caught during the entire survey but only minor and irrelevant species like the Pacific lancetfish, sharks and an opah species, Lampris guttatus. The important fishing and oceanographic factors during the survey and other research results on longline are described and analyzed. Additional longline studies within and near the Philippines territorial waters are also presented to substantiate the research results of the joint SEAFDEC/BFAR resource exploratory.
    Schlagwort(e): Fisheries ; Exploratory fishing ; Catch composition ; Fishery surveys ; Longlining ; Tuna fisheries ; South China Sea ; Philippines
    Repository-Name: AquaDocs
    Materialart: book_section
    Format: application/pdf
    Format: application/pdf
    Format: 39-48
    Format: 10
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  • 49
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26299 | 23782 | 2019-03-27 06:00:01 | 26299 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publikationsdatum: 2022-08-02
    Schlagwort(e): Chemistry ; Fisheries ; Malaysia ; Pesticides ; Biological sampling ; Fish ; Fishery products ; Biochemical analysis ; Lethal limits
    Repository-Name: AquaDocs
    Materialart: book_section
    Format: application/pdf
    Format: application/pdf
    Format: 71-74
    Format: 4
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  • 50
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26300 | 23782 | 2019-03-27 05:58:36 | 26300 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publikationsdatum: 2022-08-02
    Schlagwort(e): Aquaculture ; Chemistry ; Fisheries ; Myanmar ; Pesticides ; Biological sampling ; Fish ; Fishery products ; Lethal limits
    Repository-Name: AquaDocs
    Materialart: book_section
    Format: application/pdf
    Format: application/pdf
    Format: 75-83
    Format: 9
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  • 51
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26307 | 23782 | 2019-03-27 03:35:56 | 26307 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publikationsdatum: 2022-08-02
    Schlagwort(e): Fisheries ; Indonesia ; Histamines ; Biological sampling ; Fish ; Fishery products ; Quality control
    Repository-Name: AquaDocs
    Materialart: book_section
    Format: application/pdf
    Format: application/pdf
    Format: 116-123
    Format: 8
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  • 52
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    Unbekannt
    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26303 | 23782 | 2019-03-27 05:51:15 | 26303 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publikationsdatum: 2022-08-02
    Schlagwort(e): Chemistry ; Fisheries ; Thailand ; Pesticides ; Biological sampling ; Fish ; Fishery products ; Dried products ; Lethal limits
    Repository-Name: AquaDocs
    Materialart: book_section
    Format: application/pdf
    Format: application/pdf
    Format: 100-105
    Format: 6
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  • 53
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    Unbekannt
    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26309 | 23782 | 2019-03-27 03:49:31 | 26309 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publikationsdatum: 2022-08-02
    Schlagwort(e): Fisheries ; Myanmar ; Histamines ; Biological sampling ; Biochemical analysis ; Fish ; Fishery products
    Repository-Name: AquaDocs
    Materialart: book_section
    Format: application/pdf
    Format: application/pdf
    Format: 129-133
    Format: 5
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  • 54
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    Unbekannt
    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26826 | 23782 | 2019-11-21 00:56:12 | 26826 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publikationsdatum: 2022-08-02
    Beschreibung: Presented in the paper is the standard procedure in the determination of K value which is an index to measure the enzymatic freshness of fish and squid. Specifically, reagents, apparatus and the analytical procedures needed and the calculations are presented.
    Schlagwort(e): Chemistry ; Fisheries ; Manuals ; Culture media ; Analysis ; Analytical techniques ; Methodology ; Chemical analysis ; Fishery products ; Fish inspection ; Fishery industry ; Food technology ; Standards ; Specifications
    Repository-Name: AquaDocs
    Materialart: book_section
    Format: application/pdf
    Format: application/pdf
    Format: B-6.1-B-6.7
    Format: 7
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  • 55
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    Unbekannt
    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26825 | 23782 | 2019-11-21 00:52:35 | 26825 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publikationsdatum: 2022-08-02
    Beschreibung: Presented in the paper is the standard procedure in measuring K value in fish meat by means of the freshness testing paper technique.
    Schlagwort(e): Chemistry ; Fisheries ; Manuals ; Culture media ; Analysis ; Analytical techniques ; Methodology ; Chemical analysis ; Fishery products ; Fish inspection ; Fishery industry ; Food technology ; Standards ; Specifications
    Repository-Name: AquaDocs
    Materialart: book_section
    Format: application/pdf
    Format: application/pdf
    Format: B-7.1-B-7.2
    Format: 2
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  • 56
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    Unbekannt
    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26802 | 23782 | 2019-11-12 05:28:20 | 26802 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publikationsdatum: 2022-08-02
    Beschreibung: Presented in the paper is the standard procedure in the measurement of pH in the fresh fish meat. Specifically, the procedures in sampling and sample preparation, apparatus and reagents required, and the analytical procedures are presented.
    Schlagwort(e): Chemistry ; Fisheries ; Manuals ; Culture media ; Analysis ; Analytical techniques ; Methodology ; Chemical analysis ; Microbiological analysis ; Fishery products ; Processed fishery products ; Fish inspection ; Fishery industry ; Food additives ; Food technology ; Standards ; Specifications ; pH
    Repository-Name: AquaDocs
    Materialart: book_section
    Format: application/pdf
    Format: application/pdf
    Format: A-3.1-A-3.2
    Format: 2
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  • 57
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26842 | 23782 | 2019-11-15 07:54:48 | 26842 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publikationsdatum: 2022-08-02
    Beschreibung: Starch is commonly used in the production of fish jelly products as an extender and as binding agent. The paper provides the methodology in the determination of starch in fish jelly products. Instructions for sample preparation and the reagents needed are presented. Detailed procedures in the determination of the starch in a sample are provided.
    Schlagwort(e): Chemistry ; Fisheries ; Manuals ; Culture media ; Analysis ; Analytical techniques ; Methodology ; Chemical analysis ; Fishery products ; Fishery industry ; Food technology ; Standards ; Specifications ; Starch ; Additives ; Food additives
    Repository-Name: AquaDocs
    Materialart: book_section
    Format: application/pdf
    Format: application/pdf
    Format: D-4.1-D-4.4
    Format: 4
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  • 58
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    Unbekannt
    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26881 | 23782 | 2019-11-05 02:46:02 | 26881 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publikationsdatum: 2022-08-02
    Beschreibung: Monitoring and investigative work undertaken in the Philippines regarding dinoflagellate blooms are described. Chronological observations of the occurrence of red tides, aerial surveys, spatial distribution of the dinoflagellate and the physical environment are discussed. Fishing and the examination of gut content of fish and mussels and bioassay tests are detailed. Incidents of paralytic shellfish poisoning in the Philippines are considered briefly.
    Schlagwort(e): Fisheries ; Health ; Environmental monitoring ; Red tides ; Public health ; Medicine ; Dangerous organisms ; Philippines
    Repository-Name: AquaDocs
    Materialart: book_section
    Format: application/pdf
    Format: application/pdf
    Format: 52-79
    Format: 28
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  • 59
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26885 | 23782 | 2019-11-05 02:23:34 | 26885 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publikationsdatum: 2022-08-02
    Beschreibung: A report is made of the first incidence occurring of paralytic shellfish poisoning in Thailand in May 1983, following an extensive bloom of Trichodesmium erythraeum. Investigations undertaken regarding the source of the toxicity are outlined.
    Schlagwort(e): Fisheries ; Health ; Biological poisons ; Public health ; Red tides ; Shellfish ; Dangerous organisms ; Thailand
    Repository-Name: AquaDocs
    Materialart: book_section
    Format: application/pdf
    Format: application/pdf
    Format: 90-91
    Format: 2
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  • 60
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    Unbekannt
    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26879 | 23782 | 2019-11-05 02:54:38 | 26879 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publikationsdatum: 2022-08-02
    Beschreibung: A brief account is given of recent cases of paralytic shellfish poisoning in Sabah, Malaysia, and toxicological studies undertaken. Hydrography surveys, underwater observations after the occurrence of the red tides and plankton studies and monitoring of red tides are discussed.
    Schlagwort(e): Fisheries ; Health ; Shellfish ; Toxicity tests ; Red tides ; Public health ; Dangerous organisms ; Malaysia
    Repository-Name: AquaDocs
    Materialart: book_section
    Format: application/pdf
    Format: application/pdf
    Format: 35-42
    Format: 8
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  • 61
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26852 | 23782 | 2019-11-15 07:36:44 | 26852 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publikationsdatum: 2022-08-02
    Beschreibung: Cholera is an acute specific infection caused by the organism, Vibrio cholera. Diagnosis may be confirmed by the presence of large numbers of the comma-shaped bacilli on direct microscopic examination of a fecal or vomitus smear, and by the isolation of the organism on culture. Fish and shellfish have been identified as vehicles of cholera. Large numbers of V. cholera must usually be ingested to cause cholera. Thus problems often occur when poor handling and inadequate refrigeration have allowed the organism to multiply. Presented in the paper is the methodology of determining the presence of Vibrio cholera in fish and fishery products.
    Schlagwort(e): Chemistry ; Fisheries ; Manuals ; Culture media ; Analysis ; Analytical techniques ; Methodology ; Fishery products ; Fishery industry ; Food technology ; Standards ; Specifications ; Aerobic bacteria ; Microbiological analysis ; Microorganisms ; Pathogenic bacteria ; Pathogens ; Health and safety ; Public health ; Microbial contamination ; Vibrio cholerae
    Repository-Name: AquaDocs
    Materialart: book_section
    Format: application/pdf
    Format: application/pdf
    Format: E-7.1-E-7.5
    Format: 5
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  • 62
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    Secretariat, Southeast Asian Fisheries Development Center | Bangkok, Thailand
    In:  http://aquaticcommons.org/id/eprint/26890 | 23782 | 2019-11-14 01:01:29 | 26890 | Southeast Asian Fisheries Development Center, Secretariat
    Publikationsdatum: 2022-08-02
    Beschreibung: Fishery statistics in Brunei Darussalam have been collected by the Department of Fisheries since the 1940s. In the early 1980s, a number of statistics were collected, such as catch and effort data of artisanal fishermen, aquaculture statistics, processing statistics as well as data from major wet markets focusing on the amount, prices of marketed fish either from the local fishermen or imported. In 1984, the collection of statistics on commercial fishing was started. The statistics have been used in the formulation of fishery management and development policies as well as for sectoral development. Following a brief account of the responsibility and statistic collections of the Department of Fisheries, an examination is made of employment in the fishery sector, fisheries production, fish marketed and the GDP for the fishery industry. Fisheries in Brunei Darussalam is a very healthy industry, where production is well below the maximum allowable harvestable limit of 20,000 tons at 30%. The Department is embarking to increase production from the capture fishery to reduce the country's dependence on imported fish; the same applies for aquaculture, in order to complement production from the capture fisheries. The processing sector is also increasing in importance, especially with the increase in the number of capture fishery licenses, and the demand for quality and value-added products.
    Schlagwort(e): Fisheries ; Marine fisheries ; Fishery statistics ; Aquaculture development ; Aquaculture statistics ; Fish catch statistics ; Marine aquaculture ; Freshwater aquaculture ; Fishery development ; Marine ; Brackish ; Freshwater
    Repository-Name: AquaDocs
    Materialart: book_section
    Format: application/pdf
    Format: application/pdf
    Format: 6-14
    Format: 9
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  • 63
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26843 | 23782 | 2019-11-15 07:52:55 | 26843 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publikationsdatum: 2022-08-02
    Beschreibung: Sodium chloride is an important additive for the production of fish jelly products. It extracts the salt soluble protein to give the gel strength of the final product. The paper provides the methodology in the determination of the amount of sodium chloride in fish jelly products. Instructions for sample preparation and the reagents needed are presented. Detailed procedures in the determination of the salt in a sample are provided.
    Schlagwort(e): Chemistry ; Fisheries ; Manuals ; Culture media ; Analysis ; Analytical techniques ; Methodology ; Chemical analysis ; Fishery products ; Fishery industry ; Food technology ; Standards ; Specifications ; Additives ; Food additives ; Salts ; Sodium chloride
    Repository-Name: AquaDocs
    Materialart: book_section
    Format: application/pdf
    Format: application/pdf
    Format: D-5.1-D-5.2
    Format: 2
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  • 64
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    Marine Fisheries Research Department, Southeast Asian Fisheries Development Center | Singapore
    In:  http://aquaticcommons.org/id/eprint/26851 | 23782 | 2019-11-14 01:29:31 | 26851 | Southeast Asian Fisheries Development Center, Marine Fisheries Research Department
    Publikationsdatum: 2022-08-02
    Beschreibung: Food poisoning due to Vibrio parahaemolyticus is a food-borne infection resulting from the ingestion of a large number of this organism (about 106-109 viable cells). The major symptoms are diarrhea and abdominal pain with headache, fever, and vomiting also occurring. The organisms are excreted during the acute stage of the illness after which they decrease rapidly. The differentiation of V. parahaemolyticus from other pathogenic species of Vibrio is based mainly on salt tolerance, Voges-Proskauer reaction, fermentation of sucrose, and growth at 43°C. Presented in the paper is the methodology of determining the presence of Vibrio cholera in fish and fishery products.
    Schlagwort(e): Chemistry ; Fisheries ; Manuals ; Culture media ; Analysis ; Analytical techniques ; Methodology ; Fishery products ; Fishery industry ; Food technology ; Standards ; Specifications ; Aerobic bacteria ; Microbiological analysis ; Microorganisms ; Pathogenic bacteria ; Pathogens ; Health and safety ; Public health ; Microbial contamination ; Vibrio parahaemolyticus ; Vibrio cholerae
    Repository-Name: AquaDocs
    Materialart: book_section
    Format: application/pdf
    Format: application/pdf
    Format: E-8.1-E-8.6
    Format: 6
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  • 65
    Publikationsdatum: 2022-12-01
    Beschreibung: Die Methode der Spektrale Induzierte Polarisation (SIP) misst die Frequenzabhängigkeit des spezifischen elektrischen Widerstandes von Gesteinen nach Betrag und Phase. In der Frequenzabhängigkeit des Widerstandes spiegelt sich unter anderem die Geometrie des Porenraumes und den darin befindlichen Fluiden wieder. Üblicherweise wird das Widerstandsspektrum mit monofrequenten Signalen sequentiell vermessen. Diese Vorgehensweise erweist sich bei großskaligen Messanordnungen mit hohen Störspannungen als vorteilhaft da die Energie des Messgerätes auf einen schmalen Frequenzbereich konzentriert und eine Unterscheidung von Nutz- und Störfrequenzen erleichtert wird. Bei Labormessungen spielen Störspannungen häufig nur eine untergeordnete Rolle. Wichtiger ist hier ein möglichst hoher Messfortschritt. Am schnellsten ist die sequentielle SIP Messung, wenn jeweils nur Einzelperioden verwendet werden. Bei einer Frequenz pro Oktave, dauert die Gesamtmessung idealerweise doppelt so lange wie die längste Periode andauert. Überlagert man jedoch sämtliche Einzelfrequenzen (multifrequente Anregung) dann benötigt man nur die halbe Zeit. Der höhere Messfortschritt geht jedoch einher mit einer verringerten Messgenauigkeit. Ursache hierfür ist, dass die Einzelamplituden soweit verringert werden müssen, dass die Summenamplitude nicht die maximale Ausgangsspannung des Messgerätes überschreitet. Im Poster wird ein neu entwickeltes 88-kanaliges SIP-Labor-Messgerät (SIP-LAB-FAST) vorgestellt, das eine Anregung mit 1 - 24 Frequenzen gleichzeitig erlaubt. Bei z.B. einer Frequenz pro Octave lässt sich so ein Frequenzbereich von über 7 Dekaden mit einer Einzelmessung vermessen. Eine multifrequente Anregung erfordert auch eine leistungsfähige Hardware zur Echtzeit-Verarbeitung der Zeitreihen von Strom und Spannung. Hierzu wurde für jede Frequenz eine Diskrete Fourier Transformation (DFT) implementiert. Mittels einer multivariaten Kohärenzanalyse werden dann aus den Fourier Koeffizienten das komplexwertige Impedanz-Spektrum, sowie den zugehörigen Vertrauensintervallen berechnet. Durch die freie Wahl des Anregungssignales erhält der SIP Anwender eine erweiterte Möglichkeit den Messablauf optimal an die Fragestellung anzupassen. Ein Vergleich der mono- und multifrequenten Messergebnisse von verschiedenen Materialproben belegt die Leistungsfähigkeit der neuartigen Messtechnik.
    Beschreibung: poster
    Schlagwort(e): ddc:550 ; Geophysik ; Induzierte Polarisation
    Sprache: Deutsch
    Materialart: doc-type:conferenceObject
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  • 66
    Publikationsdatum: 2022-12-01
    Beschreibung: Over the last years, installations of wind turbines (WTs) increased worldwide. Owing to negative effects on humans, WTs are often installed in areas with low population density. Because of low anthropogenic noise, these areas are also well suited for sites of seismological stations. As a consequence, WTs are often installed in the same areas as seismological stations. By comparing the noise in recorded data before and after installation of WTs, seismologists noticed a substantial worsening of station quality leading to conflicts between the operators of WTs and earthquake services. In this study, we compare different techniques to reduce or eliminate the disturbing signal from WTs at seismological stations. For this purpose, we selected a seismological station that shows a significant correlation between the power spectral density and the hourly windspeed measurements. Usually, spectral filtering is used to suppress noise in seismic data processing. However, this approach is not effective when noise and signal have overlapping frequency bands which is the case for WT noise. As a first method, we applied the continuous wavelet transform (CWT) on our data to obtain a time-scale representation. From this representation, we estimated a noise threshold function (Langston & Mousavi, 2019) either from noise before the theoretical P-arrival (pre-noise) or using a noise signal from the past with similar ground velocity conditions at the surrounding WTs. Therefore, we installed low cost seismometers at the surrounding WTs to find similar signals at each WT. From these similar signals, we obtain a noise model at the seismological station, which is used to estimate the threshold function. As a second method, we used a denoising autoencoder (DAE) that learns mapping functions to distinguish between noise and signal (Zhu et al., 2019). In our tests, the threshold function performs well when the event is visible in the raw or spectral filtered data, but it fails when WT noise dominates and the event is hidden. In these cases, the DAE removes the WT noise from the data. However, the DAE must be trained with typical noise samples and high signal-to-noise ratio events to distinguish between signal and interfering noise. Using the threshold function and pre-noise can be applied immediately on real-time data and has a low computational cost. Using a noise model from our prerecorded database at the seismological station does not improve the result and it is more time consuming to find similar ground velocity conditions at the surrounding WTs.
    Beschreibung: poster
    Schlagwort(e): ddc:550
    Sprache: Englisch
    Materialart: doc-type:conferenceObject
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  • 67
    Publikationsdatum: 2022-12-01
    Beschreibung: As part of the German continental seismic reflection program (Deutsches Kontinentales Reflexionsseismisches Programm, DEKORP), three large seismic traverses (with the sub-profiles: DEKORP'84-2S and '86-2N; DEKORP'88-9N; DEKORP'90-3A and '90-3B) were measured in the state of Hesse in Germany. The main research topic of DEKORP were deep seismic studies to investigate the lithospheric structure beneath Germany. Thus, for acquisition, strong sources were used to image in these depths, resulting in an excellent S/N ratio, but the main focus was not on the uppermost kilometres. From today's perspective, however, this depth range is of great interest for a wide range of possible technical applications (including medium-deep and deep geothermal projects). The DEKORP profiles cover approx. 450 km in the state of Hesse and mostly cross areas where only insufficient geological data exist (i.e. only few deep boreholes). In order to close or reduce these knowledge gaps, these DEKORP lines were reprocessed in 2019/20. The focus of the reprocessing was on improving the resolution / mapping of geological structures down to a depth of 6 km (approx. 3 s TWT) to describe the prolongation of faults and geological structures in more detail than in previous studies. Nevertheless, deeper structures were also reinterpreted and compared to previous interpretations. The results were directly incorporated into the new geological 3D model of the state of Hesse, developed by the Technical University of Darmstadt (Hessen3D 2.0, BMWi-FKZ: 0325944). In order to achieve these goals and in view of the fact that today's processing methods have improved considerably compared to the 1990‘s, a state-of-the-art reprocessing was applied for all DEKORP profiles traversing the state of Hesse. In comparison to the original processing, additional processing steps like CRS instead of CDP stacking, turning-ray tomography and prestack depth migration were carried out. We present exemplary results of the reprocessing as well as initial geological reinterpretations for the profile DEKORP'88-9N.
    Beschreibung: poster
    Schlagwort(e): ddc:550 ; DEKORP ; Reprocessing of 2D seismic profiles ; Hesse ; Upper Rhine Graben ; DEKORP'88-9N
    Sprache: Englisch
    Materialart: doc-type:conferenceObject
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  • 68
    Publikationsdatum: 2022-12-01
    Beschreibung: The work presented here is part of ongoing studies in the AlpArray initiative and the priority program "MB-4D" regarding the modelling of the lithosphere in the Ligurian Sea (northwestern Mediterranean Sea). It will be based on constraining data from LOBSTER and LISA campaigns of past GEOMAR projects and a study in our research group at CAU Kiel. Our motivation is the combination and interdisciplinary interpretation of independent information from geology, tectonics, geophysics, and petrology. The existing gravity fields, especially the new compilation of the AlpArray Gravity Research Group (AAGRG) is considered as database (high resolution Free Air- and Bouguer anomalies) and the isostatic residual field, besides data of the ICGEM Potsdam (disturbance) and the ESA GOCE gradients for gravity and data for the magnetic field anomaly. The gravity and magnetic fields are analyzed using Euler deconvolution with regularization (R. Pašteka, Comenius University Bratislava) and application of curvature analysis we use both, the fields themselves and their gradients. Besides the calculation of the so-called "3rd derivative" of the gravity potential, we also investigate a possible use of the invariants of the gravity field based on gradient data and compare and correlate the results with structural and tectonic maps in the area of the Ligurian Sea and the adjacent French and Italian mainland. The findings from these comparisons will later be used to initiate the compilation of 3D density and susceptibility models for the studied region.
    Beschreibung: poster
    Schlagwort(e): ddc:550 ; Gravity gradients, ; curvature gravity field ; Gravity invariants ; Ligurean Sea
    Sprache: Englisch
    Materialart: doc-type:conferenceObject
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  • 69
    Publikationsdatum: 2022-12-01
    Beschreibung: FloodRisk is an interdisciplinary project focusing on the effects of mine water level rise in bandoned coal mine regions in Germany. Such effects are heterogeneous ground uplift, stress changes due to the change in pore pressure and the reactivation of potential faults. One of the most directly measurable effects is certainly the induced micro seismicity. It is known from previous studies that the flooding of old mines can lead to a renewed increase level in induced micro seismicity in these regions. In this study the relationship between mine water rise, fluid-induced stress changes and induced seismicity in the Haus Aden dewatering area in the eastern Ruhr area (Germany) will be investigated in more detail. For this purpose, we operate a network of currently 21 short period seismic stations in the region of the former "Bergwerk Ost" colliery, which had the highest seismicity rate in the Ruhr area during active underground coal mining. This network is still to be expanded to cover the entire water drainage area, about 30 Raspberry Shake sensors are waiting for the possibility of installation. Nevertheless, the existing network registered almost 1000 induced micro seismic events in a magnitude range from -0.7 up to 2.6 MLv. Many of these events are spatially clustered and some show quite high waveform similarity. This allows relative localisation and can increase the accuracy of the location. The depth location of the earthquakes, within the limits of localisation accuracy, agrees very well with the distribution of seismicity at the time of active mining. The spatial distribution so far seems to be limited by a large inactive transverse fault in the west. It needs to be clarified what influence this fault has on the propagation of mine water in the underground. The measured temporal trend of the mine water level, after pumps were shut down in mid-2019, shows a strong correlation with the temporal evolution of the observed micro seismicity. In the first months after the pumps are switched off, the water levels at the observation points rise only slowly and isolated microseismic events occur again. In November 2019, the rise in water levels doubled and at the same time, the strongest induced event in the measurement period was recorded with a magnitude of 2.6 MLv . In the following months, the seismicity rate ranged from 8 to 34 events above 0.5 MLv per month, some of which were felt.
    Beschreibung: Bundesministerium für Bildung und Forschung
    Beschreibung: poster
    Schlagwort(e): ddc:550 ; induced microseismicity ; FloodRisk ; waveform similarity ; raising mine water level
    Sprache: Englisch
    Materialart: doc-type:conferenceObject
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  • 70
    Publikationsdatum: 2022-12-01
    Beschreibung: We introduce an approach for 3D joint interpretation of potential fields and its derivatives under the condition of constraining data and information. The interactive 3D gravity and magnetic application IGMAS (Interactive Gravity and Magnetic Application System) has been around for more than 30 years, initially developed on a mainframe and then transferred to the first DOS PCs, before it was adapted to Linux in the ’90s and finally implemented as a cross-platform Java application with GUI. Since 2019 IGMAS+ is maintained and developed in the Helmholtz Centre Potsdam – GFZ German Research Centre by the staff of Section 4.5 – Basin Modelling and ID2 – eScience Centre. The core of IGMAS+ applies an analytical solution of the volume integral for the gravity and magnetic effect of a homogeneous body. It is based on the reduction of the three-folded integral to an integral over the bounding polyhedrons that are formed by triangles. Later the algorithm has been extended to cover all elements of the gravity tensor as well and the optimized storage enables fast leastsquares inversion of densities and changes to the model geometry and this flexibility makes geometry changes easy. Because of the triangular model structure of model interfaces, IGMAS can handle complex structures (multi- Z surfaces) like the overhangs of salt domes and variable densities due to voxelization. To account for the curvature of the Earth, we use spherical geometries. Therefore IGMAS+ is capable to handle models from big-scale to regional and small-scale models (meters) used in Applied Geophysics.
    Beschreibung: poster
    Schlagwort(e): ddc:550 ; Potential field modelling ; Complex modelling ; Visualization ; Software development
    Sprache: Englisch
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  • 71
    Publikationsdatum: 2022-12-01
    Beschreibung: A new crustal model of the Volga-Uralian subcraton was built. The compilation of the model was subdivided in two steps: (1) inverse gravity modeling followed by (2) thorough forward gravity modeling. For inverse gravity modeling GOCE gravity gradients were used. The effect of the Earth sphericity was taken into account by using tesseroids. Density contrasts between crust and mantle were varied laterally according to the tectonic units present in the region. The model is constrained by the available seismic data including receiver function studies, and deep reflection and refraction profiles. The Moho discontinuity obtained during the gravity inversion was consequently modified, and complemented by the sedimentary cover, upper crust, lower crust, and lithospheric mantle layers in the process of forward gravity modeling. Obtained model showed crustal thickness variation from 34 to more than 55 km in some areas. The thinnest crust with the thickness below 40 km appeared on the Pericaspian basin with the thickest sedimentary column. A relatively thin crust was found along the central Russia rift system, while the thickest crust is located underneath Ural Mountains as well as in the center of the Volga-Uralian subcraton. In both areas the crustal thickness exceeds 50 km. At the same time, the gravity misfit of ca. 95 mGal between the measured Bouguer gravity anomaly and forward calculated gravity field was revealed in the central area of the Volga-Uralian subcraton. This misfit was interpreted and modeled as high-density lower crust which can possibly represent an underplated material. In the end, the new crustal model of Volga-Uralian subcraton respects the gravity and seismic constraints, and reflects the main geological features of the region. This model will be used for further geothermal analysis of the area.
    Beschreibung: poster
    Schlagwort(e): ddc:550 ; Crustal model ; Gravity ; Inversion ; Volgo-Uralia ; Tesseroids ; Moho
    Sprache: Englisch
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  • 72
    Publikationsdatum: 2022-12-01
    Beschreibung: poster
    Schlagwort(e): ddc:550
    Sprache: Englisch
    Materialart: doc-type:conferenceObject
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  • 73
    Publikationsdatum: 2022-12-01
    Beschreibung: Passive seismische Messungen des Umgebungsrauschens sind effektive und nicht-invasive Methoden, um die Struktur des lokalen Untergrunds und mögliche Verstärkungen seismischer Bodenbewegungen zu ermitteln. Liegt beispielsweise Lockersediment auf Festgestein auf, so kann dies bei seismischen Ereignissen eine verstärkende Wirkung auf die seismische Beanspruchung darüberliegender Gebäude haben. Um einen ersten Überblick über den Standort zu bekommen, wird mithilfe von Einzelstationsmessungen die Fundamentalfrequenz, mit welcher der Untergrund schwingt, ermittelt (H/V-Kurven). Liegt diese in einem ähnlichen Bereich wie die Resonanzfrequenzen von Gebäuden (ca. 1 - 10 Hz) wirkt dies verstärkend, sodass auch seismische Ereignisse mit geringer Magnitude eine erhöhte Einwirkung in Bezug auf Fühlbarkeit und Schäden zur Folge haben. Des Weiteren werden zur Erstellung eines Geschwindigkeit-Tiefen-Profils mehrere Stationen zu einem Array kombiniert. Aus den gemessenen Daten werden mittels einer hochauflösenden Frequenz-Wellenzahl-Analyse (hrFK) und einer räumlichen Autokorrelation (SPAC) Dispersionskurven ermittelt, welche die Phasengeschwindigkeiten von Oberflächenwellen in Abhängigkeit der Frequenz angeben. Die resultierenden Dispersionskurven werden am Ende invertiert, um das Geschwindigkeits-Tiefen-Profil für den lokalen Untergrund zu erhalten. Insgesamt wurden auf den Flussterrassen der Weser drei Array-Messungen an unterschiedlichen Standorten, sowie mehrere H/V-Messungen durchgeführt. Ziel ist es, eine bestmögliche Strategie sowohl für die Vorgehensweise bei den Messungen, als auch für die Auswertung der Daten zu entwickeln und eine bessere Eingrenzung der Tiefenprofile der S-Wellengeschwindigkeiten zu erreichen. So wurde bei der Auswertung der Daten unter anderem eine Trennung in Love- und Rayleigh-Wellen vorgenommen, um die Geschwindigkeitsprofile besser bestimmen zu können. In Zukunft sind zudem Tests mit Variationen der Array-Geometrien geplant, um zukünftige Messungen hinsichtlich Logistik, Messdauer und Personaleinsatz zu optimieren.
    Beschreibung: poster
    Schlagwort(e): ddc:550
    Sprache: Deutsch
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  • 74
    Publikationsdatum: 2022-12-01
    Beschreibung: This presentation summarizes input data, procedures and results of probabilistic seismic hazard assessment (PSHA) in Bangladesh in the framework of the project ‘Geo information for Urban Planning and Adaptation to Climate Change’. It is a cooperation of the Geological Survey of Bangladesh (GSB) and the Federal Institute for Geosciences and Natural Resources (BGR) of Germany. The main aim of the project is to provide city planners with “Ground Suitability Maps”, which display different geo-factors. Seismic hazard is one of the geo-factors that contributes to these maps. For the derivation of “Ground Suitability Maps”, the influence of the local underground conditions will be taken into account additionally. A major part of Bangladesh is located in earthquake prone regions due to active tectonics. The Indian plate moves north-eastward towards the Eurasian plate at a velocity of about 6 cm/year. This motion leads to thrusting to the north (Himalaya) and to subduction to the east together with strike-slip mechanism. The thrusting and subduction processes have caused large historical earthquakes even inside Bangladesh (e.g. 1885 Bengal Earthquake M7 and 1918 Srimangal Earthquake M7.6). Therefore, it is crucial to assess seismic hazard in urban planning in Bangladesh. The input databases were compiled from the literature, reviewed and evaluated in this study. These are earthquake catalogs, the distribution of active faults and ground motion prediction equations. The most consistent and reliable databases were selected to be used in PSHA. The data of the earthquake catalog were declustered to eliminate the duplicated events, aftershocks and foreshocks. The spatial distribution of areal seismic sources was characterized using the distributions of earthquakes in the catalog and active faults. The completeness analysis of the earthquake catalog was performed and the Gutenberg-Richter magnitude recurrence distribution was derived for each seismic source. The results of PSHA are presented in the form of peak ground acceleration (PGA) maps with 10% exceedance probability in 50 years. As usual in regional PSHA, the results were compiled assuming bedrock as underground condition (so-called engineering bedrock with shear velocity of Vs30≥760 m/s). The northern and eastern parts of Bangladesh show the highest seismic hazard with PGA around 0.4 g with 10% exceedance probability in 50 years. This observation was expected because of the active tectonics in these parts.
    Beschreibung: poster
    Schlagwort(e): ddc:550
    Sprache: Englisch
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  • 75
    Publikationsdatum: 2022-12-01
    Beschreibung: Im Standortauswahlgesetz wird in § 22 zum Ausschlusskriterium „Seismische Aktivität“ ausgeführt, dass ein Gebiet nicht als Endlagerstandort geeignet ist, wenn die örtliche seismische Gefährdung größer als in Erdbebenzone 1 nach DIN EN 1998-1/NA:2011-01 ist. Diese Norm wird in Kürze durch eine Aktualisierung ersetzt, die dem Stand von Wissenschaft und Technik entspricht. Der Entwurf hierzu, E DIN EN 1998-1/NA:2018-10, enthält keine Zuordnungen in Erdbebenzonen mehr, sondern weist die seismische Gefährdung räumlich kontinuierlich aus. Die Bundesanstalt für Geowissenschaften und Rohstoffe (BGR) hat im Auftrag der Bundesgesellschaft für Endlagerung einen Vorschlag zur Anwendung dieses Ausschlusskriteriums unter Verwendung von E DIN EN1998-1/NA:2018-10 erarbeitet. Die BGR schlägt vor, als Grenzwert zur Anwendung des Ausschlusskriteriums den Wert der spektralen Antwortbeschleunigung im Plateaubereich von 1,8 ms-2 in E DIN EN 1998-1/NA:2018-10 zu verwenden. Dieser Wert entspricht der makroseismischen Intensität 7, für den die seismische Gefährdung größer als in Erdbebenzone 1 nach DIN EN 1998-1/NA:2011-01 ist. Für Gebiete, in denen dieser Wert überschritten wird, gilt das Ausschlusskriterium als erfüllt. Grundsätzlich ist das Ausschlusskriterium „Seismische Aktivität“ im Standortauswahlgesetz jedoch wenig geeignet, um die Erdbebengefährdung eines Standortes für ein Endlager für hochradioaktive Abfälle zu ermitteln. Der Bewertungszeitraum für die Sicherheit des Endlagers beträgt eine Million Jahre und unterscheidet sich erheblich vom Betrachtungszeitraum von 50 Jahren der Norm DIN EN 1998-1/NA. Die Intensität bzw. die Beschleunigung gilt für die Erdoberfläche; die Endlagerung hochradioaktiver Abfälle soll jedoch in tiefen geologischen Formationen erfolgen. Neben der Gefährdung aufgrund von seismischen Bodenbewegungen als Bewertungsmaßstab des Ausschlusskriteriums hat eine andere Art der Gefährdung durch Erdbeben für Endlager in tiefen geologischen Formationen eine größere Bedeutung, nämlich bruchartige Verschiebungen im Endlagerbereich. Das Ausschlusskriterium „Seismische Aktivität“ bezieht sich im Unterschied zu allen anderen Ausschlusskriterien im Standortauswahlgesetz § 22 nicht auf ein wissenschaftlich formuliertes Merkmal, sondern auf eine Norm, deren Bemessungsgrößen aufgrund eines Kompromisses zwischen Sicherheitsbetrachtungen und wirtschaftlichen Überlegungen wie erhöhten Baukosten festgelegt wurden.
    Beschreibung: poster
    Schlagwort(e): ddc:550 ; Seismische Gefährdung ; Endlagerung ; Standortauswahlgesetz ; Baunorm ; Eurocode 8
    Sprache: Deutsch
    Materialart: doc-type:conferenceObject
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  • 76
    Publikationsdatum: 2022-12-01
    Beschreibung: As part of the EPOS-Norway infrastructure project, NORSAR received funding from the Research Council of Norway for a new regional seismic array on Bjørnøya (Bear Island) in the European Arctic. After along planning phase, a six-element broadband array was installed by NORSAR staff in August 2019 and has been providing data to NORSAR in near real-time since then. Due to several logistical and administrative constraints the 6-element array has an aperture of only 300 m. All sites are equipped with Kinemetrics MBB-2 sensors and Earth Data EDR-209 digitizers that are installed in near-surface vaults. Data are automatically copied to the Norwegian node of the European Integrated Data Archive (EIDA) and are openly available. Due to environmental restrictions less than the planned 9 array sites could be installed on Bjørnøya and the non-used instruments are now available to extend the broadband station Hornsund (HSPB), Southern Spitsbergen, to another small aperture broadband array, also with 6 sites. The array installation had to be postponed because of the ongoing pandemic and is now planned for the Arctic summer 2021.
    Beschreibung: poster
    Schlagwort(e): ddc:550
    Sprache: Englisch
    Materialart: doc-type:conferenceObject
    Standort Signatur Erwartet Verfügbarkeit
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  • 77
    Publikationsdatum: 2022-12-01
    Beschreibung: Seismotectonic regions are a basic input in seismic hazard assessment. Several seismotectonic zonations for Germany have been proposed in the past. We have developed a new regionalization based on the definition in the German Nuclear Safety Standard: “A seismotectonic unit is a region for which uniformity is assumed regarding seismic activity, geological structure and development and, in particular, regarding neotectonic conditions”. Our new concept aims for transparent implementation of geological criteria, which we initially analyze separately from seismicity. We strive for a better documentation and justification of the geological elements used to delimit seismotectonic regions, based on an analysis of the geological evolution in six time slices from the Permian (300 Ma) to the Present. The time slices are separated by marked changes in the tectonic regime and associated with the development of new fault systems or reactivation of existing ones. The present-day fault network comprises faults from all time slices. For each time slice, a subset of active faults has been extracted based on geological evidence for fault activity at that time. Uncertainties of these age assignments are documented. The fault subsets delimit regions of different strain intensity. The superposition of strain intensity distributions across all time slices identifies regions affected by polyphase deformation and regions nearly undeformed over geological time, potentially indicating areas of increased or reduced present-day seismic hazard. Our new zonation consists of fewer regions than earlier ones. The geological zonation correlates well with recent seismicity in areas of Cenozoic rifting and reasonably well with less frequent earthquakes in a belt affected by Mesozoic extension and contraction. However, a few stronger earthquake cluster in regions of low geological strain. The most prominent earthquake clusters (Swabian Jura, Vogtland / NW Bohemia) also defy a simple correlation with known geological structures.
    Beschreibung: poster
    Schlagwort(e): ddc:550
    Sprache: Englisch
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  • 78
    Publikationsdatum: 2022-12-01
    Beschreibung: poster
    Schlagwort(e): ddc:550
    Sprache: Englisch
    Materialart: doc-type:conferenceObject
    Standort Signatur Erwartet Verfügbarkeit
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  • 79
    Publikationsdatum: 2022-12-01
    Beschreibung: Übertiefte Täler in den Alpen ermöglichen uns glaziale Sedimentation und somit einen Teil der quartären Klimageschichte zu verstehen. Reflexionsseimsik kann dabei verwendet werden, um punktuelle Bohrlochdaten in die Fläche zu projizieren oder eine potentielle Bohrlokation vorzuerkunden. Im Rahmen des ICDP-Projekts ‚Drilling Overdeepened Alpine Valleys‘ (DOVE) sollen eine Reihe von Bohrungen in alpinen, glazial-übertieften Tälern abgeteuft werden. Eine der Bohrungen soll 2021 in einem übertieften Tal des Rheingletschers bei Basadingen, nahe der deutsch-schweizerischen Grenze abgeteuft werden. In Zusammenarbeit mit der ETH Zürich, wurden zwei Profile im Abstand von ca. 500 m annähernd senkrecht zum Talverlauf aufgenommen. Das erste Profil ist 1246 m lang und bestand aus einer festen Auslage von 624 Geophonen. Das zweite Profil ist 1120 m lang und wurde mit 200 3-Komponenten-Geophonen im roll-along-Verfahren aufgenommen. Für beide Profile wurde bei jedem zweiten Geophon (zwei Meter Geophonabstand) mit einem hydraulischen 4-t Vibrator ein linearer 12-s-Sweep von 20-240 Hz angeregt. Beide seismischen Profile bilden ein asymmetrisches, übertieftes Becken mit ca. 260 m Tiefe ab, wobei der tiefste Bereich nur einen kleinen Teil des breiteren Hauptbeckens einnimmt. Die Auffüllung ist durch mindestens drei Diskordanzen, deutlichen Onlaps und Erosionshorizonten zwischen den Sedimenteinheiten gekennzeichnet. Wir interpretieren die Talfüllung als das Produkt eines hochdynamischen, sedimentären Systems. Der untere Teil, innerhalb des tiefsten Bereichs des Beckens, ist mit chaotisch abgelagerten Sedimenten gefüllt. Der Teil oberhalb einer Diskordanz enthält steil einfallende Reflektoren, die wahrscheinlich 20-30 m mächtige, progradierende Mäanderbanken einer glazial-fluviatilen Umgebung darstellen. Unterhalb des tiefsten Bereichs des Beckens sehen wir Versätze in Reflektoren, die auf Verwerfungen in der Tertiären Molasse hinweisen und mit bekannten Verwerfungen an der Oberfläche korrelieren. Wir vermuten, dass die Verwerfungen das Gestein geschwächt und somit die verstärkte Erosion an dieser Stelle gefördert haben.
    Beschreibung: poster
    Schlagwort(e): ddc:550 ; Seismik ; Geophysik ; Alpen ; Quartär ; übertieft ; Schweiz ; Beckenfüllung ; Sedimentation ; glazial ; Erosion ; Processing ; DMO
    Sprache: Deutsch
    Materialart: doc-type:conferenceObject
    Standort Signatur Erwartet Verfügbarkeit
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  • 80
    Publikationsdatum: 2022-12-01
    Beschreibung: As a result of the joint project ‘Subsurface Potentials for Storage and Economic Use in the North German Basin’ (German acronym: TUNB) the Geological Surveys of Northern Germany and the Federal Institute for Geosciences and Natural Resources (BGR) finalized a coherent geological 3D-model of the deep subsurface of the North German Basin in early 2021. The model consists of 13 major base surfaces from Oligocene to Zechstein, fault surfaces and hull surfaces of salt diapirs. In the northwestern part it is based on the datasets of the Tectonic Atlas of NW-Germany (GTA) along with well and seismic data from the hydrocarbon industry. Additionally to modelling the onshore part of Schleswig-Holstein and Hamburg and insuring cross-border consistency to the neighboring federal states, the Geological Survey of Schleswig-Holstein (LLUR) reconstructed a 3D-large-scale velocity model based on previous work from Jaritz et al. (1991). Their velocity approach was developed within the GTA-project and is based on sonic-log and check-shot-velocities. It assumes a linear velocity increase, which is calculated from specific global gradients for different major lithostratigraphic layers and laterally varying starting-velocities. To validate the constructed 3D-velocity-model, its velocities were compared to velocities measured at boreholes by oil and gas companies. In general, a good agreement was found between modeled and measured data (deviation 〈 5%), in which the average velocities seemed to resemble the check-shot data more accurately than the interval velocities the sonic-log-measurements. In distinct locations, the velocity model was used to convert the newly constructed TUNB-horizons from the depth- to the time-domain in order to compare them to seismic sections. Whereas overall a good agreement between horizons and seismic reflectors was found, differences were identified especially in structural complex areas. Whether these can be attributed to earlier interpretations from the GTA, the modelling of the horizons or insufficiencies in the velocity-model has yet to be determined. A follow-up project to the TUNB-project is anticipated to start in early summer 2021. The goal of the project is to derive a consistent velocity model over large parts of the North German Basin. Main challenges will be integrating available borehole and seismic data into existing velocity-modelling approaches with a special focus on establishing cross border consistency to eastern federal states.
    Beschreibung: poster
    Schlagwort(e): ddc:550
    Sprache: Englisch
    Materialart: doc-type:conferenceObject
    Standort Signatur Erwartet Verfügbarkeit
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  • 81
    Publikationsdatum: 2022-12-01
    Beschreibung: Die zerstörungsfreie Ermittlung der Materialfeuchte in Baustoffen ist für das Bauwesen von großer Bedeutung, denn ein erhöhter Feuchteeintrag kann zu Schimmelbildung, Alkali-Kieselsäure-Reaktionen, Korrosion etc. führen und somit ein hohes Schadenspotential mit sich bringen. Auch wenn zur qualitativen Lokalisierung möglicher Schad- und Risikostellen bereits zahlreiche zerstörungsfreie Verfahren in der Praxis Anwendung finden, besteht ein Mangel an quantitativen Verfahren, die auch bei niedrigen Feuchtegehalten sensitiv sind. Eine Methode zur zerstörungsfreien und quantitativen Bestimmung des Feuchtegehaltes und der effektiven Porosität ist die 1H-Kernspinresonzanzmethode (NMR). Da NMR sensitiv für die molekulare Beweglichkeit von Wasserstoffprotonen ist, lassen sich Informationen über die Bindungsform und -stärke sowie der Umgebung (Porengröße und Mineralzusammensetzung) der Wasserstoffprotonen gewinnen. Obwohl es bereits seit über 20 Jahren mobile NMR-Messeräte gibt, wird NMR heutzutage immer noch weitestgehend im Labor eingesetzt. Dies liegt daran, dass sie aufgrund der verwendeten Permanentmagnete schwer sind und nur äußerst geringe Eindringtiefen ermöglichen. In einer derzeit laufenden Forschungsarbeit wird deshalb ein speziell für Bohrkerne entworfener NMR-Tomograph eingesetzt. Mit seiner minimalen Echozeit von 50 µs lässt sich (abhängig von der Oberflächenrelaxivität) Wasser bis in nanometergroßen Poren erfassen. Um die Sensitivität von NMR bei Teilsättigung zu untersuchen, wurden verschiedene Sandsteinproben in Exsikkatoren mit relativen Luftfeuchten im Bereich von 33 % bis 96 % gelagert. Als Referenzen dienen zum einen das NMR-Signal bei Vollsättigung und zum anderen die Porengrößenverteilung aus Quecksilberporosimetriemessungen (MIP). Um die NMR-Sensitivität zu bewerten, wird die Korrelation der NMR-Amplitude mit den gravimetrisch ermittelten Feuchtegehalten sowie ein Vergleich der Porosität aus NMR und MIP betrachtet. Zu beachten ist in diesem Zusammenhang, dass sowohl die Reduzierung der Wasserfilmdicke als auch die Verkleinerung von Porengrößen zu einer ähnlichen Verkürzung der T2-Relaxationszeit führt. Als Ausblick wird ein Lösungsansatz vorgestellt, bei dem die NMR-Signale mit der Wasserfilmdickenberechnung basierend auf der relativen Luftfeuchte im Material korreliert werden.
    Beschreibung: poster
    Schlagwort(e): ddc:550
    Sprache: Deutsch
    Materialart: doc-type:conferenceObject
    Standort Signatur Erwartet Verfügbarkeit
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  • 82
    Publikationsdatum: 2022-12-01
    Beschreibung: About 25% of the Earth’s mid-ocean ridges spread at ultraslow rates of less than 20 mm/yr. However, most of these ultraslow spreading ridges are located in geographically remote areas, which hamper investigation. Consequently, how the crust forms and ages at such spreading centres, which traditional models predict to be magma-starved and cold, remains poorly understood. One of the most accessible ultra-slow spreading centres is the Mid Cayman Spreading Centre (MCSC), in the Caribbean Sea, with spreading rates of ~15-17 mm/yr. CAYSEIS project was proposed to survey the Cayman Trough area in order to obtain new data that constraints the nature of the crust, tectonic structures, lithologies outcropping and hydrothermal processes taking place in this area. Understanding the sub-seabed geophysical structure of the MCSC is key to understanding not only the lithologies and structures exposed at the seabed, but more fundamentally, how they are related at depth and what role hydrothermal fluid flow plays in the geodynamics of ultraslow spreading. CAYSEIS was a joint and multidisciplinary programme of German, British and US American top tier scientists designed for the obtaining of a new high-quality dataset, including 3D Wide-Angle Seismic (WAS), magnetic, gravimetric and seismological data. During the CAYMAN project, we took leverage of the CAYSEIS dataset to invert a 3D tomographic model of the Cayman Trough lithosphere using the Tomo3D code (Meléndez et al., 2015; 2019). This is one of the first times that the Tomo3D code is used for 3D inversion of real datasets. Thus, we are checking our results comparing them with tomographic inversions of 2D lines and testing the different parameters to obtain the more accurate and higher resolution model as possible. The results of this experiment will show not only the lithospheric structure along and across the MSCS, including the exhumed Ocean Core Complexes in the surrounding areas, but the 3D lithospheric configuration of the region which is important to understand the crustal formation processes and the evolution of ultra-slow spreading settings.
    Beschreibung: Poster
    Beschreibung: poster
    Schlagwort(e): ddc:550 ; 3D tomography ; crustal characterization ; ultra-slow spreading ; Cayman Trough
    Sprache: Englisch
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  • 83
    Publikationsdatum: 2022-12-01
    Beschreibung: The ongoing activity of Mount Etna and the proximity to the nearby population requires constant monitoring. Infrasound recordings play an important role in volcanic observation because explosive activity near or above ground as well as shallow tremor processes are easier to identify with airborne sound waves than with seismic waves that are significantly scattered and refracted in the volcano edifice. However, infrasound signals are often blurred by noise, in case of Mount Etna, mostly wind induced noise. manual distinction of noisy data from real volcanogenic signals brings along a considerable effort and requires expert knowledge. At Mount Etna five summit craters are currently known with fluctuating levels of activity. This leads to a wide variety of infrasound signal patterns interfered by changing noise levels. In order to distinguish waveforms of noise from signals of volcanic origin we apply unsupervised pattern recognition techniques. We show that by extracting features from the amplitude spectrum different infrasound regimes can be distinguished with Self-Organizing maps (SOMs). This technique provides an option to color-code the results for an intuitive interpretation and allows even for a more detailed recognition of transitional activity regimes. We create a reference data set from multiple months of infrasound waveforms to include as many activity regimes as possible to train the SOM. This enables a fast classification of new data.
    Beschreibung: poster
    Schlagwort(e): ddc:550 ; Infrasound ; Pattern Recognition ; Volcano Monitoring ; Etna
    Sprache: Englisch
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  • 84
    Publikationsdatum: 2022-12-01
    Beschreibung: In der Aeromagnetik werden zur Kampfmitteldetektion Multikopter eingesetzt, um belastete Flächen schnell und mit hoher Auflösung zu kartieren. Dabei wurden bisher hauptsächlich einzelne Totalfeldsensoren oder Fluxgate-Magnetometer verwendet, bei denen nur das Totalfeld ausgewertet wurde. Das im Rahmen dieses Projektes verwendete System besteht aus zwei dreikomponentigen Fluxgate Sensoren, einer inertialen Messeinheit (IMU) sowie einer GPS-Antenne. Die IMU erlaubt dabei, die Magnetfeldvektoren in das geographische Koordinatensystem zu projizieren und die Positionen der einzelnen Sensoren relativ zur GPS-Antenne zu bestimmen. Mit diesem Messsystem werden neben dem Totalfeld auch die Differenzen der Magnetfeldkomponenten zwischen den Sensoren ausgewertet. Die Sensoren werden in einem horizontalen Abstand von 50 cm an einem frei beweglichen, T-förmigen Ausleger unter dem Multikopter befestigt. Das Gesamtgewicht des Systems beträgt etwa 5 kg bei einer Flugzeit von 15 Minuten. Für die Inversion verwenden wir ein Dipol-Modell, das die Magnetfelddaten an den Sensorpositionen berechnet. Da bei unbekannten Störkörpern eine Differenzierung von induzierter und remanenter Magnetisierung nicht möglich ist, werden neben der Position der Störkörper deren magnetische Momente vektoriell bestimmt. Die Anzahl der angepassten Dipole und deren Startpositionen können beliebig gewählt werden. Neben dem Totalfeld können die Differenzen der Totalfelder sowie der Magnetfeldkomponenten zwischen den Sensoren zur Auswertung herangezogen werden. Um die Genauigkeit des Gesamtsystems zu untersuchen, haben wir mehrere Flüge über ein mit genau vermessenen Nd-Magneten ausgelegtes Testfeld durchgeführt. Das Testfeld umfasst eine Fläche von 100 x 20 m, aufgeteilt in vier Abschnitte mit unterschiedlichen Anomaliekonfigurationen. Für eine optimale Abdeckung und zum Vergleich der Flugrichtungen wurde die Fläche längs und quer mit einer Sensorhöhe von 1,5 m überflogen. Die Analyse der Inversionsergebnisse zeigt, dass bei Verwendung der Komponentengradienten auch überlappende Anomalien voneinander getrennt und aufgelöst werden können. Die mittleren Fehler der Positionen liegen bei 5 cm. Das magnetische Moment kann bis auf 0,35 Am^2 genau bestimmt werden, wobei die Fehler in Deklination und Inklination bei 4° bzw. 2° liegen.
    Beschreibung: poster
    Schlagwort(e): ddc:550
    Sprache: Deutsch
    Materialart: doc-type:conferenceObject
    Standort Signatur Erwartet Verfügbarkeit
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  • 85
    Publikationsdatum: 2022-12-01
    Beschreibung: Für die automatische Detektion von Erdbebenphasen in seismologischen Daten haben sich STA/LTA-Picker bewährt. In dieser Arbeit stellen wir einen alternativen Ansatz vor, der die statistischen Eigenschaften des aufgezeichneten Signals nutzt. Dafür wird die Verteilungsfunktion der gemessenen Amplituden in einem gleitenden Zeitfenster über zentrale Momente beschrieben. Insbesondere das zentrale Moment 4. Ordnung, die Wölbung oder Kurtosis, ist sensitiv gegenüber Abweichungen von der Normalverteilung. Da die Kurtosis zunimmt, sobald das Zeitfenster den Beginn einer Erdbebenphase beinhaltet, scheint sie für die Detektion von seismischen Signalen geeignet zu sein. In Kombination mit einer Polarisationsanalyse lassen sich die getriggerten Ereignisse automatisch den Einsätzen von P- und S-Wellen zuordnen. Der Polarisationsanalyse liegt ein Optimierungsproblem zugrunde, das aus der Dreikomponentenaufzeichnung der Verschiebung für ein gegebenes Zeitfenster die Richtung einer linear polarisierten Welle ermittelt, die das Verschiebungssignal am besten erklärt. Grundsätzlich wird davon ausgegangen, dass eine eintreffende Welle am Beobachtungsort relativ steil auftaucht. Entsprechend wird ein Winkel des Verschiebungsvektors gegenüber der Vertikalen zwischen 0° und 45° als P-Welle und ein Winkel zwischen 45° und 90° als S-Welle gedeutet. Der konventionelle STA/LTA-Picker und der Kurtosis-Picker wurden zusammen mit der Polarisationsanalyse hinsichtlich ihrer Zuverlässigkeit bei der Detektion und Zuordnung von Erdbebenphasen getestet. Als Vergleichsdatensatz diente die manuelle Auswertung des seismologischen Observatoriums der TU Bergakademie Freiberg in Berggießhübel mit der Registrierung an der zugehörigen Regionalnetzstation BRG. In den untersuchten Fällen lassen sich mit dem Kurtosis-Picker mehr Einsätze als mit dem STA/LTA-Picker automatisch detektieren. Der Vergleich der Triggerzeiten mit der manuellen Auswertung zeigt, dass beide Trigger die Ereignisse später als ihre manuell bestimmte Einsatzzeit erkennen. Tendenziell liegen die Triggerzeiten des Kurtosis-Pickers aber näher an den manuell bestimmten Einsatzzeiten. Die Zuordnung der detektierten Einsätze zu P- und S-Phasen funktioniert für teleseismische Ereignisse zuverlässig. Dagegen scheint die Zuordnung für Krustenphasen von Nahbeben und Steinbruchsprengungen nicht immer perfekt zu funktionieren.
    Beschreibung: poster
    Schlagwort(e): ddc:550
    Sprache: Deutsch
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  • 86
    Publikationsdatum: 2022-12-01
    Beschreibung: DFG FOR 2825
    Beschreibung: poster
    Schlagwort(e): ddc:550 ; Ultrasound ; Coda Wave Interferometry ; Bridge Monitoring
    Sprache: Englisch
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  • 87
    Publikationsdatum: 2022-12-01
    Beschreibung: poster
    Schlagwort(e): ddc:550
    Sprache: Englisch
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  • 88
    Publikationsdatum: 2022-12-01
    Beschreibung: Nach Auftreten eines Feuchteschadens in Fußbodenaufbauten sind sowohl die zeitnahe Feststellung als auch Eingrenzung betroffener Bereiche von besonderer Bedeutung. So können erforderliche Renovierungsmaßnahmen effizient geplant und mögliche Folgeschäden vermieden werden. Zur messtechnischen Beantwortung dieser Fragestellungen werden bereits seit vielen Jahren Neutronensonden eingesetzt, welche allerdings keine Tiefenzuordnung des schadensträchtigen Flüssigwassers zulassen. Hierzu müssen mit hohem zeitlichem und finanziellem Aufwand zerstörende Sondierungsbohrungen vorgenommen werden, welche zukünftig durch den parallelen Einsatz des Radarverfahrens vermieden werden könnten. In systematischen Laborstudien wurden gängige Feuchteschäden an häufig anzutreffenden Fußbodenaufbauten simuliert und deren Einfluss auf das Messsignal untersucht. Hierbei kamen Zementund Anhydritestriche, sowie die Dämmmaterialen Styropor, Styrodur, Glaswolle und Perlite-Schüttung mit variierenden Schichtdicken zum Einsatz, um die vielfältigen Konfigurationen der Praxis abzubilden. Für den gewonnenen Datensatz konnten geeignete Signalmerkmale extrahiert werden, welche mithilfe multivariater Datenauswertung eine Klassifizierung des vorliegenden Schadenfalls zulassen. Zum Ende des Forschungsvorhabens steht besonders die Anwendbarkeit der entwickelten Methoden für die Praxis im Fokus. Hierzu wurden Messungen an realen Schadensfällen durchgeführt und deren Ergebnisse mit den Laboruntersuchungen verglichen. Hierbei stellten sich variierende Schichtdicken, sowie vorkommende Fußbodenheizungen und Armierungsgitter als mögliche Fehlerquellen für eine vollständig automatisierte Auswertung heraus.
    Beschreibung: poster
    Schlagwort(e): ddc:550 ; Radar ; Feuchte ; Fußboden ; Neutronensonde
    Sprache: Deutsch
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  • 89
    Publikationsdatum: 2022-12-01
    Beschreibung: Due to a complex interplay between the Earth and overlying ice sheets, a large variety of subglacial landforms developed. One example is the in the North German Basin widely spread phenomenon of tunnel valleys. An observed correlation to underlying salt structures is often explained mechanically. We focus on an alternative hypothesis based on thermodynamic processes: As salt better conducts heat than the surrounding rocks, the geothermal heat flux is augmented above salt structures. This leads to melting processes at the interface between the Earth and the ice sheet. The subglacial rivers finally erode the tunnel valleys. To test this hypothesis, we model related hydrothermal processes by means of a finite-difference open-source code (SHEMAT-Suit). The model accounts for heat conduction, groundwater flows, processes in the glaciothermal system such as the motion and spatiotemporal temperature evolution within the ice, and finally the coupling of both at the subglacial interface to account for the feedback mechanisms. Glaciothermal system and coupling processes are incorporated based on an idealized 1D model for the ice cover. We present a scaling analysis to discuss dominant processes. Our results show that a purely conductive subsurface (complete absence of groundwater flow) leads to a very moderate increase of the geothermal heat flux above salt structures. This implies a slight increase of the melting rates, which by itself is not enough to trigger tunnel valley erosion. Additional hydrothermal flows e.g. through fault zones may increase the subglacial melting rates. In this contribution, we will present results from a case study in the Southern North Sea. A 2D seismic section includes two tunnel valleys above salt structures. To model the state prior to erosion and sedimentation during and after the Quaternary glaciations, the Quaternary strata is replaced by strata with the same physical properties and thicknesses than the Paleocene to Miocene strata. Simulation runs with SHEMAT-Suite calculated the subsurface temperature distribution and the geothermal heat flux distribution at the subglacial interface. This allows assessing the subglacial melting rates along with the temperature profile within the ice cover for a number of glaciation scenarios. Current results show that thermodynamic processes reinforce the formation of tunnel valleys together with e.g. mechanical weakening by faulting.
    Beschreibung: poster
    Schlagwort(e): ddc:550
    Sprache: Englisch
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  • 90
    Publikationsdatum: 2022-12-01
    Beschreibung: poster
    Schlagwort(e): ddc:550
    Sprache: Deutsch
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  • 91
    Publikationsdatum: 2022-12-01
    Beschreibung: A combination of noninvasive geophysical magnetic gradiometery and electrical resistivity tomography (ERT) was employed to locate the remains of an old church form the 9th century in Neuss-Norf, Germany. The gradiometery survey was carried out along 27 parallel profiles oriented approximately E–W with a profile spacing of 1 m and a sampling spatial interval of 0.5 m along each profile in order to detect the distributions of the possible buried walls of the church and other related archaeological remains. The vertical gradient of the magnetic field, with a fixed distance of 1.04 m between the sensors, was measured. The lower sensor was fixed at a height of 0.32 m from the ground surface. The magnetic data were transferred to the frequency domain using Fast Fourier transform then reduced to the magnetic pole. The analytic signal and power spectrum techniques were applied to the obtained magnetic data. Moreover, ERT measurements were performed based on the results of the magnetic survey along 12 profiles utilizing the Wenner and Dipole-Dipole arrays with 0.5 m electrode spacing. The ERT data from both arrays were merged into one dataset to form a non-conventional mixed array. The ERT data were inverted into 2D resistivity models using robust (blocky) inversion technique, and then a 3D resistivity prospective was created. The combined interpretation of the magnetic and ERT showed that the archaeological structures are close to the ground surface with a maximum depth of up to 2 m. We successfully detected anomalous zones that could be associated with the walls of at least one ancient church-building in addition to several possible archaeological structures in the survey area. A considerable agreement between the results of both methods was observed. Highly magnetic sources that could be associated with metallic objects within tomb-like structures were detected. An archaeological map of the possible location of the old church and the assumed surrounding tombs and features was constructed. Finally, some promising places were suggested in order to start an archaeological excavation in the site based on the findings of our research.
    Beschreibung: poster
    Schlagwort(e): ddc:550 ; Archaeogeophysics; ERT; Magnetic gradiometery; Neuss-Norf, Germany
    Sprache: Englisch
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  • 92
    Publikationsdatum: 2022-12-01
    Beschreibung: The German continental seismic reflection program DEKORP (DEutsches KOntinentales Reflexionsseismisches Programm) was carried out in the years between 1984 and 1999. The aim of DEKORP was to investigate the deep crustal structure of Germany with high-resolution near-vertical incidence (mostly vibro)seismic acquisition, supplemented by wide-angle seismic and other target-oriented piggy-back experiments, all complemented by optimized methods of data processing and interpretation. The DEKORP project was an equivalent to many other deep-seismic programs world-wide such as COCORP, BIRPS, LITHOPROBE, ECORS, CROP, BELCORP, IBERSEIS and others. The resulting DEKORP database consists of approximately 40 crustal-scale 2D-seismic reflection lines covering a total of ca. 4 700 km and one 3D-seismic survey covering ca. 400 km², recorded in close connection with the German Continental Deep Drilling Program (KTB). Nowadays, re-recording of these seismic traverses in the same extent and quality would often not be possible anymore due to increased acquisition costs and tightened permission requirements. Therefore these datasets provide unique and deep insights into the subsurface below Germany covering the earth’s crust from the surface to the upper mantle. Currently, many of the original raw data are still stored on old storage media and in formats, which can only be read by special devices, programs and experts. To prevent the final loss of this valuable geoscientific treasure an initiative at GFZ transcripts all relevant DEKORP data to modern formats and media. Over the last few years the demand for DEKORP data continuously increased. Several academic institutions and commercial companies reprocess and/or reinterpret these data, which lead to significant improvements in the quality of the results. Fields of applications are geothermal development, hazard analysis, hydrocarbon/shale gas exploration, underground gas storage, tunnel construction, disposal of nuclear waste and more. To simplify the data access for the scientific as well as for the commercial geo-community, a well-structured provision and utilisation concept is being developed. The concept includes so-called data publications with DOIs, a defined license model and automised retrieval for each of the surveys providing raw data, processed data, meta data, related links and more. The plan aims to have all relevant DEKORP datasets compiled and prepared for access via web interface till 2022.
    Beschreibung: poster
    Schlagwort(e): ddc:550
    Sprache: Englisch
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  • 93
    Publikationsdatum: 2022-12-01
    Beschreibung: NEXD is an open source software package for the simulation of seismic waves in complex geological media. This includes elastic, viscoelastic, porous and fractured media with complex geometries. For the computation of the wave fields, the nodal discontinuous Galerkin approach (NDG) is used. The NDG approach combines unstructured tetrahedral meshes with an element-wise, high-order spatial interpolation of the wave field based on Lagrange polynomials. NEXD offers capabilities for modeling wave propagation in one-, two- and three-dimensional settings of very different spatial scale with little logistical overhead. It allows the import of external triangular (2D) and tetrahedral (3D) meshes provided by independent meshing software and can be run in a parallel computing environment. The computation of adjoint wavefields and an interface for the computation of waveform sensitivity kernels are offered. The method is verified by means of symmetry tests and the method of exact solutions. The capabilities of NEXD are demonstrated through, for example, a 2D synthetic survey of a geological carbon storage site. The most recent developments have been the inclusion of porous media in 2D and the inversion capabilities to the latest release versions of the 2D and 3D codes as well as the release of the 1D code. NEXD is available on GitHub: https://github.com/seismology-RUB.
    Beschreibung: poster
    Schlagwort(e): ddc:550 ; Numerical modelling ; Computational seismology ; Wave propagation
    Sprache: Englisch
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  • 94
    Publikationsdatum: 2022-12-01
    Beschreibung: The ocean worlds of our Solar System, like Saturn's moon Enceladus and Jupiter's moon Europa are covered with ice. Recently, these icy moons gained further scientific interest, as they are attributed some potential to sustain or host extraterrestrial life in a subglacial ocean. The investigation of these moons will also help to understand the evolution of the Solar System. The in-situ exploration of these moons requires novel technological solutions as well as intelligent data acquisition and interpretation tools. In 2020, the DLR Space Administration started the TRIPLE project (Technologies for Rapid Ice Penetration and subglacial Lake Exploration) which develops an integrated concept for a melting probe that launches an autonomous underwater vehicle (nanoAUV) into a scientifically interesting water reservoir and an AstroBioLab for in-situ analysis. These three components build up the TRIPLE system. As part of a second project stage, it is envisioned to build the TRIPLE system and test it in Antarctica in 2026. In this contribution, we are going to present the general concept of TRIPLE with a focus on the geophysically most relevant aspects. To navigate the melting probe through the ice, a forefield reconnaissance system (TRIPLE-FRS) based on combined radar and sonar techniques is designed. This will include radar antennas directly integrated into the melting head combined with a pulse amplifier and a piezoelectric acoustic transducer just behind the melting head. In addition, an in-situ permittivity sensor will be implemented to account for the ice structure dependent propagation speed of electromagnetic waves. With this system, obstacles as well as the ice-water interface at the bottom of the icy shell could be detected. To deliver key parameters such as transit time and overall energy requirement, a virtual test bed for strategic mission planning is currently under development. This consists of the Ice Data Hub that combines available data from Earth or any other planetary body – measured or taken from the literature – and allows display, interpretation and export of data, as well as trajectory models for the melting probe. We develop high-fidelity thermal contact models for the phase change as well as macroscopic trajectory models that consider the thermodynamic melting process and the convective loss of heat via the melt-water flow.
    Beschreibung: Bundesministerium für Wirtschaft und Energie (FKZ: 50NA1908, 50RK2050, 50RK2051, 50RK2052, 50RK2053)
    Beschreibung: poster
    Schlagwort(e): ddc:550 ; Icy Moon ; mission concept ; ice melting probe ; reconnaissance
    Sprache: Englisch
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  • 95
    Publikationsdatum: 2022-12-01
    Beschreibung: Stahlfaserbeton (FRC) ist ein zementgebundener Hochleistungswerkstoff, der in vielen Bereichen des Bauwesens breite Anwendung gefunden hat, insbesondere dort, wo hohe Zugfestigkeit, strukturelle Integrität und innovatives Design gewünscht sind. Zu den großen Vorteilen dieses Materials gehören seine geringe Anfälligkeit für Rissbildung, seine Undurchlässigkeit für aggressive Substanzen (z. B. Enteisungsmittel) und die reduzierten Anforderungen an zusätzlich eingebettete Stahlbewehrung. Tatsächlich ist es je nach Form eines FRC-Bauteils auch möglich, die klassischen Bewehrungsstäbe komplett durch Stahlfasern zu ersetzen. Auf diese Weise lassen sich erhebliche Mengen an Beton einsparen, der logistische und ökologische Fußabdruck reduzieren und gleichzeitig gewinnen Ingenieure und Designer ein hohes Maß an Flexibilität bei der Schaffung schlanker und leichter Strukturen. Die strukturelle Integrität hängt, wie fast alle der oben genannten Eigenschaften von FRC, in hohem Maße vom tatsächlichen Gehalt an Fasern und deren räumlicher Orientierung ab. Stahlfasern können sich sogar nachteilig auswirken, wenn sie ungünstig verteilt oder orientiert sind. Solche ungünstigen herstellungsbedingten Faserorientierungen und -verteilungen können z. B. ein unerwünschtes anisotropes Materialverhalten verursachen. Für einen sicheren Einsatz von FRC in der Zukunft müssen zuverlässige zerstörungsfreie Methoden gefunden werden, um die Orientierung und räumliche Verteilung der Fasern im erhärteten Beton zu beurteilen. In diesem Beitrag stellen wir einen Multimethodenansatz vor, der sich auf Ultraschalltransmissions- (US) und Spektral Induzierter Impedanz (SIP) sowie Röntgen-Computertomografie (CT) stützt. Wir haben eine Reihe von Proben mit bekannten Fasergehalten und -orientierungen in verschiedenen Größen hergestellt und versucht, charakteristische Signalmerkmale zu identifizieren. Aufgrund des hohen Kontrasts zwischen der Röntgenschwächung von Stahlfasern und Beton ist die Faserdetektion mittels CT relativ einfach und das Verfahren kann als Referenzmethode verwendet werden. Vielversprechende Korrelationen konnten darüber hinaus zwischen SIP-Signalmerkmalen und Faserorientierung erkannt werden, gleichzeitig beobachteten wir leichte Verschiebungen in den Ultraschallfrequenzspektren in Abhängigkeit von der Faserorientierung innerhalb unserer Proben. Die Übertragbarkeit der Ergebnisse auf in-situ Untersuchungen großformatiger Probekörper wird in einem nächsten Schritt untersucht.
    Beschreibung: poster
    Schlagwort(e): ddc:550
    Sprache: Deutsch
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  • 96
    Publikationsdatum: 2022-12-01
    Beschreibung: Deutsche Forschungsgemeinschaft
    Beschreibung: poster
    Schlagwort(e): ddc:550
    Sprache: Englisch
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  • 97
    Publikationsdatum: 2022-12-01
    Beschreibung: Modelling the propagation of seismic waves in porous media gets more and more popular in the seismological community since it is an important but challenging task in the field of computational seismology. The fluid content of, for example, reservoir rocks or soils, and the interaction between the fluid and the rock or between different immiscible fluids has to be taken into account to accurately describe seismic wave propagation through such porous media. Often, numerical models are based on the elastic wave equation and some might include artificially introduced attenuation. This simplifies the problem but only approximates the true physics involved. Hence, the results are also simplified and could lack accuracy or miss phenomena in some applications. The aim of the conducted work was the consistent derivation of a theory for seismic wave propagation in porous media saturated by two immiscible fluids and the accompanying numerical solution for the derived wave equation. The theory is based on Biot's theory of poroelasticity. Starting from the basic conservation equations (energy, momentum, etc.) and generally accepted laws, the theory was derived using a macroscopic approach which demands that the wavelength is significantly larger than the size of the heterogeneities in the medium due to the size of the grains and pores or due to effects on the mesoscopic scale. This condition is usually fulfilled for seismic waves since the typical wavelength of seismic waves is in the order of 10 m to 10 km. Fluid flow is described by a Darcy type flow law and interactions between the fluids by means of capillary pressure curve models. In addition, consistent boundary conditions on interfaces between poroelastic media and elastic or acoustic media are derived from this poroelastic theory itself. The nodal discontinuous Galerkin method is used for the numerical modelling. The poroelastic solver is integrated into the 1D and 2D codes of the larger software package NEXD that uses the nodal discontinuous Galerkin method to solve wave equations. The implementation has been verified using symmetry tests and the method of exact solutions. This work has potential for applications in various scientific fields like, for example, exploration and monitoring of hydrocarbon or geothermal reservoirs as well as CO2 storage sites.
    Beschreibung: poster
    Schlagwort(e): ddc:550
    Sprache: Englisch
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  • 98
    Publikationsdatum: 2022-12-01
    Beschreibung: Der Semail Ophiolith im Osten der arabischen Halbinsel ist einer der größten und am besten zugänglichen Ophiolithkomplexe der Welt. Um die Obduktion und die weiteren Prozesse, die bei seiner Entstehung eine Rolle gespielt haben, umfassend verstehen zu können, wird eine genaue Kenntnis seiner Struktur und der darunter liegenden Kruste benötigt. Während das Material des Ophiolithen selbst, sowie die obere Kruste bereits in mehreren Studien eingehend untersucht wurde, fehlen vor allem in der unteren Kruste Informationen über ihren Aufbau und dort vorherrschende Dichteverteilungen. Ein vorhandenes 2D Modell der Kruste stützt sich auf Informationen aus 2D Seismik, Bohrlöchern und Reciever Funktionen. Kombiniert mit geologischen Informationen liefert dieses Modell detaillierte Schichtungen und Dichtewerte bis in 15 km Tiefe und ist konsistent zur dort oberflächlich gemessenen Bougueranomalie. Es enthält allerdings nur wenige Informationen zur Geometrie der Unterkruste und der Krusten-Mantel-Grenze, welche nun basierend auf einer neuen seismischen S-Wellen-Tomographie ergänzt werden. Zur Anpassung des modifizierten Modells an die Bougueranomalie, wurde anhand der Geschwindigkeitsverteilung in der seismischen Tomographie die Dichteverteilung der unteren Kruste abgeschätzt, so dass das Modell konsistent zu den vorhandenen Beobachtungswerten ist. Neben diesem 2D Modell bietet das neue 3D-Vs-Modell die Möglichkeit, laterale Variationen in der Bouguerschwere im gesamten Omangebirge genauer zu untersuchen.
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    Schlagwort(e): ddc:550
    Sprache: Deutsch
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  • 99
    Publikationsdatum: 2022-11-29
    Beschreibung: Fachsession für die geowissenschaftlichen Fachreferate, Online Workshop organisiert von FID GEO, FID Karten und FID Montan
    Beschreibung: DFG
    Beschreibung: presentation
    Schlagwort(e): ddc:550 ; Open Access
    Sprache: Deutsch
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  • 100
    Publikationsdatum: 2022-11-29
    Beschreibung: Der Fachinformationsdienst Geowissenschaften (FID GEO) veranstaltete zusammen mit der geowissenschaftlichen Bibliothek des Geologisches Instituts (GIA) der RWTH Aachen, einen Workshop zu den rechtlichen Fragen der Open-Access-Veröffentlichungen in den Geowissenschaften. Neben der Publikationsunterstützung des FID GEO ging es in dieser Veranstaltung vor allem um die rechtlichen Voraussetzungen des Publizierens in geowissenschaftlichen Verlagen. Dabei wurden die Möglichkeiten und Hürden für junge Wissenschaftler*innen aufgezeigt sowie auf konkrete Verlagsbeispiele eingegangen.
    Beschreibung: DFG, SUB Göttingen
    Beschreibung: presentation
    Schlagwort(e): ddc:550 ; Open Access ; Urheberrecht
    Sprache: Deutsch
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