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Retrospective short-term forecasting experiment in Italy based on the occurrence of strong (fore) shocks (2021)

Gasperini, Paolo ; Biondini, Emanuele ; Lolli, Barbara ; [weitere]

Oxford University Press

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Publikationsdatum: 2021-03-15

Beschreibung: In a recent work we computed the relative frequencies with which strong shocks (4.0≤Mw〈5.0), widely felt by the population were followed in the same area by potentially destructive main shocks (Mw≥5.0) in Italy. Assuming the stationarity of the seismic release properties, such frequencies can be tentatively used to estimate the probabilities of potentially destructive shocks after the occurrence of future strong shocks. This allows us to set up an alarm-based forecasting hypothesis related to strong foreshocks occurrence. Such hypothesis is tested retrospectively on the data of a homogenized seismic catalogue of the Italian area against a purely random hypothesis that simply forecasts the target main shocks proportionally to the space-time fraction occupied by the alarms. We compute the latter fraction in two ways a) as the ratio between the average time covered by the alarms in each area and the total duration of the forecasting experiment (60 years) and b) as the same ratio but weighted by the past frequency of occurrence of earthquakes in each area. In both cases the overall retrospective performance of our forecasting algorithm is definitely better than the random case. Considering an alarm duration of three months, the algorithm retrospectively forecasts more than 70% of all shocks with Mw5.5 occurred in Italy from 1960 to 2019 with a total space-time fraction covered by the alarms of the order of 2%. Considering the same space-time coverage, the algorithm is also able to retrospectively forecasts more than 40% of the first main shocks with Mw5.5 of the seismic sequences occurred in the same time interval. Given the good reliability of our results, the forecasting algorithm is set and ready to be tested also prospectively, in parallel to other ongoing procedures operating on the Italian territory.

Beschreibung: This paper benefitted from funding provided by the European Union within the ambit of the H2020 project RISE (No. 821115), which in particular fully financed the PhD grant of one of the authors (E.B.).

Beschreibung: Published

Beschreibung: 1192–1206

Beschreibung: 6T. Studi di pericolosità sismica e da maremoto

Beschreibung: JCR Journal

Schlagwort(e): Earthquake interaction ; Statistical seismology ; forecasting, ; prediction ; 04.06. Seismology

Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)

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Thermal structure of a vanishing subduction system. An example of seismically-derived crustal temperature along the Italian peninsula (2020)

Diaferia, Giovanni ; Cammarano, Fabio ; Faccenna, Claudio

Oxford University Press

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Publikationsdatum: 2020-10-16

Beschreibung: This article has been accepted for publication in Geophysical Journal International ©: The Authors 2019. 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: The active tectonic processes in convergent margins confer a high degree of complexity to the crust. Determining the thermal structure is, therefore, key to better elucidate the nature of those processes. In order to reconstruct the thermal structure of the crust beneath the Italian peninsula, we combine the most recent and accurate shear-wave velocity model that is currently available with thermodynamic modelling, assuming a global average crustal composition with no lateral variations. Our model, presented in terms of Moho temperature and crustal thermal gradients, shows a very good agreement with the known thermal anomalies associated with the backarc spreading related to the Apennine subduction. Importantly, we envisage a new anomalous region of high Moho temperatures in NW Italy (T 〉 800 degrees C at 30 km), at the transition between the Alps and Apennine orogens. The lowest temperatures of our model, corresponding to geothermal gradients 〈 19 degrees C km(-1), are obtained in the still active but slow-convergent portion of the northern Apennine. Moho temperatures increase moving southwards along the Apennine chain, an observation that is coherent with the evidence of ceasing subduction and consequent rebalancing of the depressed isotherms along the slab. Our results suggest that a thermal structure in different tectonic settings can be inferred with acceptable uncertainties based on absolute seismic velocity models. In this sense, our approach can be extended to any other region.

Beschreibung: Published

Beschreibung: 239–247

Beschreibung: 1T. Struttura della Terra

Beschreibung: JCR Journal

Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)

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3

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Magnitude-dependent epidemic-type aftershock sequences model for earthquakes (2020)

Spassiani, Ilaria ; Sebastiani, Giovanni

American Physical Society

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Publikationsdatum: 2020-10-16

Beschreibung: We propose a version of the pure temporal epidemic type aftershock sequences (ETAS) model: the ETAS model with correlated magnitudes. As for the standard case, we assume the Gutenberg-Richter law to be the probability density for the magnitudes of the background events. Instead, the magnitude of the triggered shocks is assumed to be probabilistically dependent on that of the relative mother events. This probabilistic dependence is motivated by some recent works in the literature and by the results of a statistical analysis made on some seismic catalogs [Spassiani and Sebastiani, J. Geophys. Res. 121, 903 (2016)10.1002/2015JB012398]. On the basis of the experimental evidences obtained in the latter paper for the real catalogs, we theoretically derive the probability density function for the magnitudes of the triggered shocks proposed in Spassiani and Sebastiani and there used for the analysis of two simulated catalogs. To this aim, we impose a fundamental condition: averaging over all the magnitudes of the mother events, we must obtain again the Gutenberg-Richter law. This ensures the validity of this law at any event's generation when ignoring past seismicity. The ETAS model with correlated magnitudes is then theoretically analyzed here. In particular, we use the tool of the probability generating function and the Palm theory, in order to derive an approximation of the probability of zero events in a small time interval and to interpret the results in terms of the interevent time between consecutive shocks, the latter being a very useful random variable in the assessment of seismic hazard.

Beschreibung: Published

Beschreibung: 042134

Beschreibung: 6T. Studi di pericolosità sismica e da maremoto

Beschreibung: JCR Journal

Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)

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4

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Aseismic transient driving the swarm-like seismic sequence in the Pollino range, Southern Italy (2020)

Passarelli, Luigi ; Hainzl, Sebastian ; Cesca, Simone ; [weitere]

Oxford University Press

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Publikationsdatum: 2020-12-15

Beschreibung: This article has been accepted for publication in Geophysical Journal International ©: The Authors 2015. 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: ectonic earthquake swarms challenge our understanding of earthquake processes since it is difficult to link observations to the underlying physical mechanisms and to assess the hazard they pose. Transient forcing is thought to initiate and drive the spatio-temporal release of energy during swarms. The nature of the transient forcing may vary across sequences and range from aseismic creeping or transient slip to diffusion of pore pressure pulses to fluid redistribution and migration within the seismogenic crust. Distinguishing between such forcing mechanisms may be critical to reduce epistemic uncertainties in the assessment of hazard due to seismic swarms, because it can provide information on the frequency–magnitude distribution of the earthquakes (often deviating from the assumed Gutenberg–Richter relation) and on the expected source parameters influencing the ground motion (for example the stress drop). Here we study the ongoing Pollino range (Southern Italy) seismic swarm, a long-lasting seismic sequence with more than five thousand events recorded and located since October 2010. The two largest shocks (magnitude M w = 4.2 and M w = 5.1) are among the largest earthquakes ever recorded in an area which represents a seismic gap in the Italian historical earthquake catalogue. We investigate the geometrical, mechanical and statistical characteristics of the largest earthquakes and of the entire swarm. We calculate the focal mechanisms of the M l 〉 3 events in the sequence and the transfer of Coulomb stress on nearby known faults and analyse the statistics of the earthquake catalogue. We find that only 25 per cent of the earthquakes in the sequence can be explained as aftershocks, and the remaining 75 per cent may be attributed to a transient forcing. The b-values change in time throughout the sequence, with low b-values correlated with the period of highest rate of activity and with the occurrence of the largest shock. In the light of recent studies on the palaeoseismic and historical activity in the Pollino area, we identify two scenarios consistent with the observations and our analysis: This and past seismic swarms may have been ‘passive’ features, with small fault patches failing on largely locked faults, or may have been accompanied by an ‘active’, largely aseismic, release of a large portion of the accumulated tectonic strain. Those scenarios have very different implications for the seismic hazard of the area.

Beschreibung: Published

Beschreibung: 1553–1567

Beschreibung: 4T. Sismicità dell'Italia

Beschreibung: JCR Journal

Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)

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5

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Non-stability of the noise HVSR at sites near or on topographic heights (2021)

La Rocca, Mario ; Chiappetta, Giuseppe Davide ; Gervasi, Anna ; [weitere]

Oxford University Press

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Publikationsdatum: 2021-01-18

Beschreibung: The horizontal to vertical spectral ratio (HVSR) of seismic noise is often used to investigate site effects, and it is usually assumed to be a stable feature of the site considered. Here we show that such an assumption is not always justified, and may lead to incorrect conclusions. The HVSR analysis was performed on ambient seismic noise recordings lasting from weeks to months at many sites in Calabria, Italy. Results show a variety of site effects, from the resonance of a shallow sedimentary layer to the polarized amplification of horizontal ground motion associated with topographic effects. We describe the results of seven sites whose HVSR is characterized by dual content: one that is persistent, and another appearing only occasionally. Two sites very near the coast of the Tyrrhenian sea and five sites in the Calabrian Arc mountains show the most remarkable results. The shape of the HVSR changes significantly at these sites when the amplitude of background noise increases in a broad frequency band during periods of bad weather. The occasional contribution to the HVSR consists of one or more peaks, depending on the site, that appear only when the amplitude of ambient noise is higher than usual. The seven sites where we observe the HVSR variability are all located in complex geological environments, on mountains, ridges or foothills. A variation of the HVSR correlated with the day–night cycle is also observed at some of these sites.

Beschreibung: Published

Beschreibung: 2162–2171

Beschreibung: 1T. Struttura della Terra

Beschreibung: JCR Journal

Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)

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6

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The Shallow Plumbing System of Piton de la Fournaise Volcano (La Reunion Island, Indian Ocean) Revealed by the Major 2007 Caldera-Forming Eruption (2021)

Di Muro, A. ; Metrich, N. ; Vergani, D ; [weitere]

Oxford University Press

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Publikationsdatum: 2021-02-10

Beschreibung: The 2007 caldera-forming eruption of Piton de la Fournaise (PdF) erupted the largest volume of magma (210 Mm3)recorded at this volcano in at least three centuries. Major and trace element and Sr^Nd isotope data for bulk-rocks, groundmasses and olivine phenocrysts have been combined with melt inclusion data (major, trace and volatile elements) to track magma evolution over the whole eruptive sequence. We show that each eruptive phase had a distinctive geochemical and petrological signature and that caldera collapse on 5 April was preceded by a marked shift in bulk magma composition and crystal content and size. Aphyric basalt erupted at the beginning of the sequence (February 2007) had relatively high Sr isotope ratio (87Sr/86Sr ¼ 0·70420^0·704180) and low Nd isotopic ratio(143Nd/144Nd ¼ 0·51285^0·51286). Olivine-basalts extruded on2^5 April just before caldera collapse are less enriched in radiogenic Sr (87Sr/86Sr ¼ 0·70412^0·70416), but characterized by the same Nd isotopic composition. This magma is interpreted as a new deep input, which pressurized the shallow PdF plumbing system and triggered the 2007 activity. Post-collapse oceanite lavas represent the main volume of magma extruded in 2007. Their bulk-rocks and groundmasses have 87Sr/86Sr (0·70418) intermediate between those of February and 5 April, and similar to those of the March 2007 and 2001^2006 lavas.We show that the Steady State Basalts (SSB) commonly erupted at PdF are hybrid melts, which result from multistep mixing between ‘alkaline’and ‘transitional’end-members. Our results lead us to propose a new model of the PdF plumbing system to reconcile the petrological, geochemical and geophysical observations: (1) the shallow portion (above sea level) of the PdF plumbing system hosts several small sills, in which magma experiences variable degrees of degassing, cooling and crystallization; (2) oceanite lavas result from the withdrawal of shallow harrisitic mushes stored at low pressures (548 MPa; 51800^2400 m depth) below both the volcano summit and its eastern flank; (3) water degassing plays a major role in fast magma crystallization at shallow depths. Multistep ascent and periodic extrusion of the shallow magmas is promoted by injections of deeper and hotter basaltic magma, containing up to 1·3 wt % H2O and 1630 ppm S. In 2007, the new deep input was the ultimate source of the large excess in sulfur degassing detected by satellites. Lateral draining and intrusion of magma below the eastern flank of the volcano are the cause of major volcano deformation, flank sliding and summit caldera collapse.

Beschreibung: Published

Beschreibung: 1287-1315

Beschreibung: 2V. Struttura e sistema di alimentazione dei vulcani

Beschreibung: 3V. Proprietà chimico-fisiche dei magmi e dei prodotti vulcanici

Beschreibung: 4V. Processi pre-eruttivi

Beschreibung: 6A. Geochimica per l'ambiente e geologia medica

Beschreibung: JCR Journal

Schlagwort(e): Piton de la Fournaise ; plumbing system ; magma reservoir ; caldera collapse ; melt inclusions ; volatile budget ; isotope geochemistry ; basalt

Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)

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7

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Numerical analysis of interseismic, coseismic and postseismic phases for normal and reverse faulting earthquakes in Italy (2021)

Albano, Matteo ; Barba, Salvatore ; Bignami, Christian ; [weitere]

Oxford University Press

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Publikationsdatum: 2021-02-23

Beschreibung: The preparation, initiation, and occurrence dynamics of earthquakes in Italy are governed by several frequently unknown physical mechanisms and parameters. Understanding these mechanisms is crucial for developing new techniques and approaches for earthquake monitoring and hazard assessments. Here, we develop a first-order numerical model simulating quasi-static crustal interseismic loading, coseismic brittle episodic dislocations, and postseismic relaxation for extensional and compressional earthquakes in Italy based on a common framework of lithostatic and tectonic forces. Our model includes an upper crust, where the fault is locked, and a deep crust, where the fault experiences steady shear.

Beschreibung: Published

Beschreibung: 627–645

Beschreibung: 2T. Deformazione crostale attiva

Beschreibung: JCR Journal

Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)

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An automatically generated high-resolution earthquake catalogue for the 2016–2017 Central Italy seismic sequence, including P and S phase arrival times (2021)

Spallarossa, Daniele ; Cattaneo, Marco ; Scafidi, Davide ; [weitere]

Oxford University Press

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Publikationsdatum: 2021-03-24

Beschreibung: The 2016–17 central Italy earthquake sequence began with the first mainshock near the town of Amatrice on August 24 (MW 6.0), and was followed by two subsequent large events near Visso on October 26 (MW 5.9) and Norcia on October 30 (MW 6.5), plus a cluster of 4 events with MW 〉 5.0 within few hours on January 18, 2017. The affected area had been monitored before the sequence started by the permanent Italian National Seismic Network (RSNC), and was enhanced during the sequence by temporary stations deployed by the National Institute of Geophysics and Volcanology and the British Geological Survey. By the middle of September, there was a dense network of 155 stations, with a mean separation in the epicentral area of 6–10 km, comparable to the most likely earthquake depth range in the region. This network configuration was kept stable for an entire year, producing 2.5 TB of continuous waveform recordings. Here we describe how this data was used to develop a large and comprehensive earthquake catalogue using the Complete Automatic Seismic Processor (CASP) procedure. This procedure detected more than 450,000 events in the year following the first mainshock, and determined their phase arrival times through an advanced picker engine (RSNI-Picker2), producing a set of about 7 million P- and 10 million S-wave arrival times. These were then used to locate the events using a non-linear location (NLL) algorithm, a 1D velocity model calibrated for the area, and station corrections and then to compute their local magnitudes (ML). The procedure was validated by comparison of the derived data for phase picks and earthquake parameters with a handpicked reference catalogue (hereinafter referred to as ‘RefCat’). The automated procedure takes less than 12 hours on an Intel Core-i7 workstation to analyse the primary waveform data and to detect and locate 3000 events on the most seismically active day of the sequence. This proves the concept that the CASP algorithm can provide effectively real-time data for input into daily operational earthquake forecasts, The results show that there have been significant improvements compared to RefCat obtained in the same period using manual phase picks. The number of detected and located events is higher (from 84,401 to 450,000), the magnitude of completeness is lower (from ML 1.4 to 0.6), and also the number of phase picks is greater with an average number of 72 picked arrival for a ML = 1.4 compared with 30 phases for RefCat using manual phase picking. These propagate into formal uncertainties of ± 0.9km in epicentral location and ± 1.5km in depth for the enhanced catalogue for the vast majority of the events. Together, these provide a significant improvement in the resolution of fine structures such as local planar structures and clusters, in particular the identification of shallow events occurring in parts of the crust previously thought to be inactive. The lower completeness magnitude provides a rich data set for development and testing of analysis techniques of seismic sequences evolution, including real-time, operational monitoring of b-value, time-dependent hazard evaluation and aftershock forecasting.

Beschreibung: Published

Beschreibung: 555–571

Beschreibung: 3T. Fisica dei terremoti e Sorgente Sismica

Beschreibung: JCR Journal

Schlagwort(e): 04.06. Seismology

Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)

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9

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Erratum: On seismic ambient noise cross-correlation and surface-wave attenuation (2021)

Boschi, Lapo ; Magrini, Fabrizio ; Cammarano, Fabio ; [weitere]

Oxford University Press

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Publikationsdatum: 2021-05-12

Beschreibung: erratum paper

Beschreibung: Published

Beschreibung: 1090-1092

Beschreibung: 1T. Struttura della Terra

Beschreibung: JCR Journal

Schlagwort(e): Theoretical seismology ; Seismic attenuation ; Seismic noise ; Surface waves ; Free oscillations ; Seismic interferometry ; 04.06. Seismology ; 04.01. Earth Interior

Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)

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10

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Crustal structure of the Azores Archipelago from Rayleigh wave ellipticity data (2021)

Berbellini, Andrea ; Frietsch, Michael ; Attanayake, Januka ; [weitere]

Oxford University Press

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Publikationsdatum: 2021-05-12

Beschreibung: This article has been accepted for publication inGeophysical Journal International ©The Author(s) 2020. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

Beschreibung: Determining the crustal structure of ocean island volcanoes is important to understand the formation and tectonic evolution of the oceanic lithosphere and tectonic swells in marine settings, and to assess seismic hazard in the islands. The Azores Archipelago is located near a triple junction system and is possibly under the influence of a mantle plume, being at the locus of a wide range of geodynamic processes. However, its crustal structure is still poorly constrained and debated due to the limited seismic coverage of the region and the peculiar linear geometry of the islands. To address these limitations, in this study we invert teleseismic Rayleigh wave ellipticity measurements for 1-D shear wave speed (VS) crustal models of the Azores Archipelago. Moreover, we test the reliability of these new models by using them in independent moment tensor inversions of local seismic data and demonstrate that our models improve the waveform fit compared to previous models. We find that data from the westernmost seismic stations used in this study require a shallower Moho depth (∼10 km) than data from stations in the eastern part of the archipelago (∼13–16 km). This apparent increase in the Moho depth with increasing distance from the mid-Atlantic ridge (MAR) is expected. However, the rate at which Moho deepens away from the MAR is greater than that predicted from a half-space cooling model, suggesting that local tectonic perturbations have modified crustal structure. The 1-D VS models obtained beneath the westernmost seismic stations also show higher wave speeds than for the easternmost stations, which correlates well with the ages of the islands except Santa Maria Island. We interpret the relatively low VS profile found beneath Santa Maria Island as resulting from underplating, which agrees with previous geological studies of the island. Compared to a recent receiver function study of the region, the shallow structure (top ∼2 km) in our models shows lower shear wave speed, which may have important implications for future hazard studies of the region. More generally, the new seismic crustal models we present in this study will be useful to better understand the tectonics, seismicity, moment tensors and strong ground motions in the region.

Beschreibung: Published

Beschreibung: 1232–1247

Beschreibung: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica

Beschreibung: JCR Journal

Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)

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Changing modes and rates of mafic magma supply at Pantelleria (Sicily Channel, Southern Italy): new perspectives on the volcano factory drawn upon olivine records (2021)

Giuffrida, Marisa ; Nicotra, Eugenio ; Viccaro, Marco

Oxford University Press

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Publikationsdatum: 2021-05-12

Beschreibung: The island of Pantelleria, located in the Sicily Channel Rift Zone (Italy), has been the site of violent peralkaline silicic magmatism alternating with minor effusive to low-intensity Strombolian erup- tions of basaltic composition. The basaltic rock suites exposed on the island were sampled to in- vestigate the plumbing system dynamics through the study of chemical stratigraphy and temporal records of olivine crystals. Our petrographic and geochemical observations, together with the com- positional variability of olivine, suggest different evolutionary histories for basaltic magmas erupted over two major periods divided by the 􏰃45 ka Green Tuff (GT) eruption. Core-to-rim com- positional traverses across olivine crystals document different types of zoning. We recognized oliv- ine zones affected by Fo oscillations at very fine scales in the inner cores, rims and/or in intermedi- ate portions of crystals and used them to reconstruct the residence and passage of crystals through different magmatic environments, with P–T–ƒO2 and compositional characteristics con- strained by thermodynamic modeling. The sequence of magmatic environments evidenced by oliv- ine zoning indicate that the pre-GT volcanic period was dominated by injection at shallow crustal levels (􏰃300–200 MPa) of primitive melts, initially moving from a deep storage zone at the crust- mantle boundary. Supply of this magma significantly decreased after the GT eruption, while the dy- namics of magma transfer within the upper portion of the plumbing system were greatly enhanced. The diffusive relaxation of olivine zoning provided the timing of storage and migration of a crystal through different environments. For magmas feeding the ancient (〉45 ka) basaltic activ- ity we retrieved transfer histories that are much longer (up to 􏰃3 years) if compared with those cal- culated for the post-GT basalts (1–9 months). The compositional and temporal dataset presented in this study supports the idea that the GT eruption and the subsequent collapse of the volcanic edi- fice could have caused major changes to the internal structural setting of Pantelleria, creating more favorable conditions for the migration of magmas in the upper portions of the plumbing system.

Beschreibung: Published

Beschreibung: egaa05

Beschreibung: 2V. Struttura e sistema di alimentazione dei vulcani

Beschreibung: JCR Journal

Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)

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The Deep Plumbing System of Ischia: a Physico-chemical Window on the Fluid-saturated and CO2-sustained Neapolitan Volcanism (Southern Italy) (2021)

Moretti, Roberto ; Arienzo, Ilenia ; Orsi, Giovanni ; [weitere]

Oxford University Press

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Publikationsdatum: 2021-05-12

Beschreibung: Ischia, a volcanic island located 18 miles SW of Naples (Southern Italy), is a densely populated active caldera that last erupted in AD 1302. Melt inclusions in phenocrysts of the Vateliero and Cava Nocelle shoshonite^latite eruptive products (6th to 4th centuries BC) constrain the structure and nature of the Ischia deep magmatic feeding system.Their geochemical characteristics make Ischia a natural borehole for probing the physico-chemical conditions of magma generation in mantle contaminated by slab-derived fluids or melts, largely dominated by CO2.Volatile concentrations in olivine-hosted melt inclusions require gas^melt equilibria at between 3 and 18 km depth. In agreement with what has already been demonstrated at the other neighboring Neapolitan volcanoes (Procida, Campi Flegrei caldera and Somma^Vesuvius volcanic complex), a major crystallization depth at 8^10 km has been identified.The analyzed melt inclusions provide clear evidence for CO2-dominated gas fluxing and consequent dehydration of magma batches stagnating at crustal discontinuities. Gas fluxing is further supported by selective enrichment in K owing to fluid-transfer during magma differentiation.This takes place under oxidized conditions (Fe3þ /Fe 0·3) that can be fixed by an equimolar proportion of divalent and trivalent iron in the melt if post-entrapment crystallization of the host olivine is discarded.The melt inclusion data, together with data from the literature for other Neapolitan volcanoes, show that magmatism and volcanism in the Neapolitan area, despite differences in composition and eruption dynamics, are closely linked to supercritical CO2-rich fluids. These fluids are produced by devolatilization of subducting terrigenous^pelagic metasediments and infiltrate the overlying mantle wedge, generate magmas and control their ascent up to eruption. Geochemical characteristics of Ischia and the other Neapolitan volcanoes reveal that the extent of fluid or melt contamination of the pre-subduction asthenospheric mantle wedge was similar among these volcanoes. However, differences in the isotopic compositions of the erupted magmas (more enriched in radiogenic Sr at Ischia, Campi Flegrei and Somma^Vesuvius with respect to Procida) and the amount of H2O in the plumbing system of these volcanoes (almost double at Ischia, Campi Flegrei and Somma^Vesuvius than at Procida) reflect the different flow-rates of deep slab-derived fluids or melts through the mantle wedge, which, in turn, control the amount of generated magma.The high bulk permeability of the lithosphere below Ischia, Campi Flegrei and Somma^Vesuvius, determined by the occurrence of intersecting NW^SE and NE^SW regional fault systems, favours fluid ascent and accumulation at crustal levels, with consequent larger magma production and storage than at Procida, located along the NE^SW system.

Beschreibung: Published

Beschreibung: 951-984

Beschreibung: 2V. Struttura e sistema di alimentazione dei vulcani

Beschreibung: 3V. Proprietà chimico-fisiche dei magmi e dei prodotti vulcanici

Beschreibung: 4V. Processi pre-eruttivi

Beschreibung: 6A. Geochimica per l'ambiente e geologia medica

Beschreibung: JCR Journal

Schlagwort(e): CO2-fluxing ; melt inclusions ; redox state ; trachybasalts

Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)

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Sulphur behaviour and redox conditions in etnean magmas during magma differentiation and degassing (2021)

Gennaro, Mimma Emanuela ; Paonita, Antonio ; Iacono-Marziano, Giada ; [weitere]

Oxford University Press

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Publikationsdatum: 2021-06-21

Beschreibung: Sulphur behaviour and variations in redox conditions during magma differentiation and degassing in the Mt Etna (Italy) volcanic system have been explored by integrating the study of olivine-hosted melt inclusions (MIs) with an experimental survey of sulphur solubility in hydrous basaltic magmas. Sulphur solubility experiments were performed at conditions relevant to the Etnean plumbing system (1200 C, 200MPa and oxygen fugacity between NNOþ0 2 and NNOþ1 7, with NNO being the nickel–nickel oxide buffer), and their results confirm the important control of oxygen fugacity (fO2) on S abundance in mafic magmas and on S partitioning between fluid and melt phases (DSfluid/melt). The observed DSfluid/melt value increases from 5164 to 14666 when fO2 decreases from NNOþ1 760 5 to NNOþ0 3. Based on the calculated DSfluid/melt and a careful selection of previously published data, an empirical model is proposed for basaltic magmas to predict the variation of DSfluid/melt values with variations in P (25–300 MPa), T (1030–1200 C) and fO2 (between NNO– 0 8 and NNOþ2 4). Olivine-hosted melt inclusions (Fo89-91) from tephra of the prehistoric (4 ka BP) sub-plinian picritic eruption, named FS (‘Fall Stratified’), have been investigated for their major element compositions, volatile contents and iron speciation (expressed as Fe3þ/PFe ratio). These primitive MIs present S content from 235677 to 34456168 ppm, and oxygen fugacity values, estimated from Fe3þ/PFe ratios, range from NNOþ0 760 2 to NNOþ1 660 2. Iron speciation has also been investigated in more evolved and volatile-poorer Etnean MIs. The only primitive melt inclusion from the Mt Spagnolo eruption (4–15 ka BP) presents a S content of 1515649ppm and an estimated fO2 of NNOþ1 460 1. The more evolved MIs (from 2002–2003, 2006, 2008–2009 and 2013 eruptions) have S content lower than 500 ppm, and their Fe3þ/RFe ratios result in fO2 between NNO– 0 960 1 and NNOþ0 460 1. Redox conditions and S behaviour in Etnean magmas during degassing and fractional crystallization were modelled coupling MELTS code with our empirical DSfluid/melt model. Starting from an FS-type magma composition and upon decrease of T and P, fractional crystallization of olivine, clinopyroxene, spinel and plagioclase causes a significant fO2 decrease. The fO2 reduction, in turn, causes a decrease in sulphur solubility and an increase in DSfluid/melt, promoting S exsolution during magma ascent, which further enhances the reduction of fO2. For the evolved MIs of 2002–2013 eruptions, magma differentiation may therefore have played a crucial role in decreasing redox conditions and favouring efficient S degassing. Differently, during the unusual FS eruption, only limited melt evolution is observed and S exsolution seems to have been triggered by a major pressure decrease accompanied by H2O and CO2 exsolution during fast magmatic ascent.

Beschreibung: Published

Beschreibung: egaa095

Beschreibung: 4V. Processi pre-eruttivi

Beschreibung: JCR Journal

Schlagwort(e): melt inclusions ; sulphur solubility experiments ; XANES ; Mt. Etna ; 04.08. Volcanology

Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)

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Importance of earthquake rupture geometry on tsunami modelling: the Calabrian Arc subduction interface (Italy) case study (2020)

Tonini, Roberto ; Basili, Roberto ; Maesano, Francesco Emanuele ; [weitere]

Oxford University Press

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Publikationsdatum: 2020-10-16

Beschreibung: The behaviour of tsunami waves at any location depends on the local morphology of the coasts, the encountered bathymetric features, and the characteristics of the source. However, the importance of accurately modelling the geometric properties of the causative fault for simulations of seismically induced tsunamis is rarely addressed. In this work, we analyse the effects of using two different geometric models of the subduction interface of the Calabrian Arc (southern Italy, Ionian Sea) onto the simulated tsunamis: a detailed 3-D subduction interface obtained from the interpretation of a dense network of seismic reflection profiles, and a planar interface that roughly approximates the 3-D one. These models can be thought of as representing two end-members of the level of knowledge of fault geometry. We define three hypothetical earthquake ruptures of different magnitudes (Mw 7.5, 8.0, 8.5) on each geometry. The resulting tsunami impact is evaluated at the 50-m isobath in front of coastlines of the central and eastern Mediterranean. Our results show that the source geometry imprint is evident on the tsunami waveforms, as recorded at various distances and positions relative to the source. The absolute differences in maximum and minimum wave amplitudes locally exceed one metre, and the relative differences remain systematically above 20 per cent with peaks over 40 per cent. We also observe that tsunami energy directivity and focusing due to bathymetric waveguides take different paths depending on which fault is used. Although the differences increase with increasing earthquake magnitude, there is no simple rule to anticipate the different effects produced by these end-member models of the earthquake source. Our findings suggest that oversimplified source models may hinder our fundamental understanding of the tsunami impact and great care should be adopted when making simplistic assumptions regarding the appropriateness of the planar fault approximation in tsunami studies. We also remark that the geological and geophysical 3-D fault characterization remains a crucial and unavoidable step in tsunami hazard analyses.

Beschreibung: Published

Beschreibung: 1805–1819

Beschreibung: 3T. Sorgente sismica

Beschreibung: 6T. Studi di pericolosità sismica e da maremoto

Beschreibung: JCR Journal

Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)

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On the Heterogeneity of the Earthquake rupture (2021)

Malagnini, Luca ; Dreger, Douglas Scott ; Nadeau, Robert M ; [weitere]

Oxford University Press

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Publikationsdatum: 2021-04-14

Beschreibung: The scaling of earthquake parameters with seismic moment and its interpretation in terms of self- similarity is still debated in the literature. We address this question by examining a worldwide compilation of corner frequency-based and elastic rebound theory (ERT)-based fault slip, area and stress drop values for earthquakes ranging in magnitude from -0.7 to 7.8. We find that corner frequency estimates of slip (and stress drop) scale differently than those inferred from the ERT approach, where the latter deviates from the generally accepted constant stress drop behavior of so- called self-similar scaling models. We also find that average slips from finite-source models are consistent with corner frequency scaling, whereas peak slip values are more consistent with the ERT scaling. The different scaling of corner frequency- and ERT-based estimates of slip and stress drop with earthquake size is interpreted in terms of heterogeneity of the rupture process. ERT-based estimates of stress drop decrease with seismic moment suggesting a self-affine behavior. Despite the inferred heterogeneity at all scales, we do not observe a clear effect on the Brune stress drop scaling with earthquake size.

Beschreibung: Published

Beschreibung: 1771–1781

Beschreibung: 2T. Deformazione crostale attiva

Beschreibung: JCR Journal

Schlagwort(e): Earthquake dynamics ; Earthquake source observations ; Dynamics and mechanics of faulting ; 04.06. Seismology

Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)

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Back to the future: old methods for new estimation and test of the Gutenberg–Richter b-value for catalogues with variable completeness (2020)

Taroni, Matteo

Oxford University Press

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Publikationsdatum: 2020-11-11

Beschreibung: This article has been accepted for publication in Geophysical Journal International ©: 2021 The Author(s) 2020. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

Beschreibung: In this short paper we show how to use the classical maximum likelihood estimation procedure for the b-value of the Gutenberg–Richter law for catalogues with different levels of completeness. With a simple correction, that is subtracting the relative completeness level to each magnitude, it becomes possible to use the classical approach. Moreover, this correction allows to adopt the testing procedures, initially made for catalogues with a single level of completeness, for catalogues with different levels of completeness too.

Beschreibung: Published

Beschreibung: 337–339

Beschreibung: 6T. Studi di pericolosità sismica e da maremoto

Beschreibung: JCR Journal

Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)

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Good practices in PSHA: declustering, b-value estimation, foreshocks and aftershocks inclusion; a case study in Italy (2020)

Taroni, Matteo ; Akinci, Aybige

Oxford University Press

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Publikationsdatum: 2020-12-21

Beschreibung: This article has been accepted for publication in Geophysical Journal International. Published by Oxford University Press on behalf of the Royal Astronomical Society.

Beschreibung: The classical procedure of the Probabilistic Seismic Hazard Analysis (PSHA) requires a Poissonian distribution of earthquakes. Seismic catalogs follow a Poisson distribution just after the application of a declustering algorithm that leaves only one earthquake for each seismic sequence (usually the stronger, i.e. the main shock). Removing earthquakes from the seismic catalogs leads to underestimation of the annual rates of the events and consequently associate with low seismic hazard as indicated by several studies. In this study, we aim investigating the performance of two declustering methods on the Italian instrumental catalog and the impact of declustering on estimation of the b-value and on the seismic hazard analysis. To this end, first the spatial variation in the seismicity rate was estimated from the declustered catalogs using the adaptive smoothed seismicity approach, considering small earthquakes (Mw≥3.0). We then corrected the seismicity rates using new approach that allows for counting all events in the complete seismic catalog by simply changing the magnitude frequency distribution. The impact of declustering on seismic hazard analysis is illustrated using PSHA maps in terms of peak ground acceleration (PGA) and spectral acceleration (SA) in 2 s, with 10% and 2% probability of exceedance in 50 years, for Italy. We observed that the hazard calculated from the declustered catalogs was always lower than the hazard computed using the complete catalog. These results are in agreement with previous results obtained in different parts of the world.

Beschreibung: Published

Beschreibung: 1174–1187

Beschreibung: 6T. Studi di pericolosità sismica e da maremoto

Beschreibung: JCR Journal

Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)

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Crustal and uppermost mantle shear wave velocity structure beneath the Middle East from surface wave tomography (2021)

Sandvol, Eric ; Tang, Zheng ; Lu, Yang ; [weitere]

Oxford University Press

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Publikationsdatum: 2021-05-12

Beschreibung: We have constructed a 3-D shear wave velocity (Vs) model for the crust and uppermost mantle beneath the Middle East using Rayleigh wave records obtained from ambient-noise cross-correlations and regional earthquakes. We combined one decade of data collected from 852 permanent and temporary broad-band stations in the region to calculate group-velocity dispersion curves. A compilation of 〉54 000 ray paths provides reliable group-velocity measurements for periods between 2 and 150 s. Path-averaged group velocities calculated at different periods were inverted for 2-D group-velocity maps. To overcome the problem of heterogeneous ray coverage, we used an adaptive grid parametrization for the group-velocity tomographic inversion. We then sample the period-dependent group-velocity field at each cell of a predefined grid to generate 1-D group-velocity dispersion curves, which are subsequently inverted for 1-D Vs models beneath each cell and combined to approximate the 3-D Vs structure of the area. The Vs model shows low velocities at shallow depths (5–10 km) beneath the Mesopotamian foredeep, South Caspian Basin, eastern Mediterranean and the Black Sea, in coincidence with deep sedimentary basins. Shallow high-velocity anomalies are observed in regions such as the Arabian Shield, Anatolian Plateau and Central Iran, which are dominated by widespread magmatic exposures. In the 10–20 km depth range, we find evidence for a band of high velocities (〉4.0 km s–1) along the southern Red Sea and Arabian Shield, indicating the presence of upper mantle rocks. Our 3-D velocity model exhibits high velocities in the depth range of 30–50 km beneath western Arabia, eastern Mediterranean, Central Iranian Block, South Caspian Basin and the Black Sea, possibly indicating a relatively thin crust. In contrast, the Zagros mountain range, the Sanandaj-Sirjan metamorphic zone in western central Iran, the easternmost Anatolian plateau and Lesser Caucasus are characterized by low velocities at these depths. Some of these anomalies may be related to thick crustal roots that support the high topography of these regions. In the upper mantle depth range, high-velocity anomalies are obtained beneath the Arabian Platform, southern Zagros, Persian Gulf and the eastern Mediterranean, in contrast to low velocities beneath the Red Sea, Arabian Shield, Afar depression, eastern Turkey and Lut Block in eastern Iran. Our Vs model may be used as a new reference crustal model for the Middle East in a broad range of future studies.

Beschreibung: Published

Beschreibung: 1349-1365

Beschreibung: 1T. Struttura della Terra

Beschreibung: JCR Journal

Schlagwort(e): 04.01. Earth Interior ; 04.06. Seismology

Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)

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Scenario analysis can guide aquaculture planning to meet sustainable future production goals (2021)

Couture, Jessica L. ; Froehlich, Halley E. ; Buck, Bela H. ; [weitere]

Oxford University Press

In: EPIC3ICES Journal of Marine Science, Oxford University Press, pp. 1-11, ISSN: 1054-3139

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Publikationsdatum: 2021-07-23

Beschreibung: Marine aquaculture holds great promise for meeting increasing demand for healthy protein that is sustainably produced, but reaching necessary production levels will be challenging. The ecosystem approach to aquaculture is a framework for sustainable aquaculture development that prioritizes multiple-stakeholder participation and spatial planning. These types of approaches have been increasingly used to help guide sustainable, persistent, and equitable aquaculture planning, but most countries have difficulties in setting or meeting longer-term development goals. Scenario analysis (SA) for future planning uses similar approaches and can complement holistic methods, such as the ecosystem approach to aquaculture framework, by providing a temporal analogue to the spatially robust design. Here we define the SA approach to planning in aquaculture, outline how SA can benefit aquaculture planning, and review how this tool is already being used. We track the use of planning tools in the 20 International Council for the Exploration of the Sea member nations, with particular attention given to Norway’s development goals to 2050. We conclude that employing a combination of an ecosystem framework with scenario analyses may help identify the scale of development aquaculture goals over time, aid in evaluating the feasibility of the desired outcomes, and highlight potential social-ecological conflicts and trade-offs that may otherwise be overlooked.

Repository-Name: EPIC Alfred Wegener Institut

Materialart: Article , isiRev

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Eruptive activity on the western flank of Piton de la Fournaise (La Réunion Island, Indian Ocean): insights on magma transfer, storage and evolution at an oceanic volcanic island (2020)

Boudoire, Guillaume ; Brugier, Yann-Aurélien ; Di Muro, Andréa ; [weitere]

Oxford University Press

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Publikationsdatum: 2020-06-17

Beschreibung: Petrological and geochemical (major element, trace element, Sr–Nd isotope) data for recent (〈5 kyr old) basalts that sporadically erupt on the western flank of Piton de la Fournaise (PdF), one of the most active volcanoes on Earth, allow the tracking of magma transfer and evolution from mantle to crustal depths. In the western peripheral area of PdF we document the broadly synchronous eruptions of (1) primitive olivine and olivine–clinopyroxene transitional basalts with tholeiitic affinity 30 that are closely associated in space with (2) transitional olivine basalts with alkaline affinity, and (3) hybrid lavas, intermediate between the ‘alkaline’ and the ‘tholeiitic’ end-members. The composition of the latter overlaps with that of the lavas frequently erupted from the conduit system feeding the main summit cone. AlphaMELTS modelling, and fluid inclusion and clinopyroxene barometry, constrain the conditions of magma storage at 10–30 km, and the ascent of magma from the upper 35 mantle to the shallow crustal plumbing system. Variable degrees of mantle melting, together with minor source heterogeneity and contamination with cumulate-derived partial melts, contribute to the diversity of PdF magmas. However, all these processes do not represent the dominant factors that produce the large variability we found in major element composition. Indeed, the composition of basalts erupted from PdF peripheral centers is strongly controlled by polybaric olivine–clinopyr- 40 oxene fractionation at pressures higher than 3 kbar. Crystal textures and geochemical modelling suggest that fast magma ascent is critical to prevent clinopyroxene dissolution. Conversely, longlasting magma stagnation promotes pyroxene resorption and magma differentiation. ‘Central’ eruptions occurring close to the PdF summit cone emit variably more evolved melts, which result from olivine–clinopyroxene–plagioclase differentiation at intermediate–shallow pressure (〈3 kbar and in most cases 〈1 kbar). Deep and extensive magma mixing before injection into the crustal magma conduit system, located below the summit region, results in the apparent homogeneity of basalts erupted from the central area. As regards ‘peripheral’ eruptions, deep-seated stagnation of basaltic melts and differentiation at the mantle–crust transition zone (c. 4 kbar) produces a range of 5 magma compositions. We demonstrate that rapid magma ascent from deep-seated reservoirs can bypass the central plumbing system. The eruptions of these magmas both in the central area and on the densely populated flanks have major consequences in terms of volcanic hazard at PdF.

Beschreibung: Published

Beschreibung: 1717–1752

Beschreibung: 2V. Struttura e sistema di alimentazione dei vulcani

Beschreibung: JCR Journal

Schlagwort(e): transitional basalts ; clinopyroxene crystallization and resorption ; mantle–crust underplating

Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)

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Evaluating learning spaces in flood risk management in Germany: Lessons for governance research (2021)

Witting, Antje ; Brandenstein, Frederick ; Kochskämper, Elisa

Blackwell Publishing Ltd | Oxford, UK

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Publikationsdatum: 2021-06-28

Beschreibung: Efforts to collaboratively manage the risk of flooding are ultimately based on individuals learning about risks, the decision process, and the effectiveness of decisions made in prior situations. This article argues that much can be learned about a governance setting by explicitly evaluating the relationships through which influential individuals and their immediate contacts receive and send information to one another. We define these individuals as “brokers,” and the networks that emerge from their interactions as “learning spaces.” The aim of this article is to develop strategies to identify and evaluate the properties of a broker's learning space that are indicative of a collaborative flood risk management arrangement. The first part of this article introduces a set of indicators, and presents strategies to employ this list so as to systematically identify brokers, and compare their learning spaces. The second part outlines the lessons from an evaluation that explored cases in two distinct flood risk management settings in Germany. The results show differences in the observed brokers' learning spaces. The contacts and interactions of the broker in Baden‐Württemberg imply a collaborative setting. In contrast, learning space of the broker in North Rhine‐Westphalia lacks the same level of diversity and polycentricity.

Beschreibung: Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659

Beschreibung: MWK Baden‐Württemberg

Schlagwort(e): 333.91 ; brokerage ; collaborative water governance ; comanagement ; comparative analysis ; social networks

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Synthetic resampling strategies and machine learning for digital soil mapping in Iran (2021)

Taghizadeh‐Mehrjardi, Ruhollah ; Schmidt, Karsten ; Eftekhari, Kamran ; [weitere]

Blackwell Publishing Ltd | Oxford, UK

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Publikationsdatum: 2021-07-04

Beschreibung: Most common machine learning (ML) algorithms usually work well on balanced training sets, that is, datasets in which all classes are approximately represented equally. Otherwise, the accuracy estimates may be unreliable and classes with only a few values are often misclassified or neglected. This is known as a class imbalance problem in machine learning and datasets that do not meet this criterion are referred to as imbalanced data. Most datasets of soil classes are, therefore, imbalanced data. One of our main objectives is to compare eight resampling strategies that have been developed to counteract the imbalanced data problem. We compared the performance of five of the most common ML algorithms with the resampling approaches. The highest increase in prediction accuracy was achieved with SMOTE (the synthetic minority oversampling technique). In comparison to the baseline prediction on the original dataset, we achieved an increase of about 10, 20 and 10% in the overall accuracy, kappa index and F‐score, respectively. Regarding the ML approaches, random forest (RF) showed the best performance with an overall accuracy, kappa index and F‐score of 66, 60 and 57%, respectively. Moreover, the combination of RF and SMOTE improved the accuracy of the individual soil classes, compared to RF trained on the original dataset and allowed better prediction of soil classes with a low number of samples in the corresponding soil profile database, in our case for Chernozems. Our results show that balancing existing soil legacy data using synthetic sampling strategies can significantly improve the prediction accuracy in digital soil mapping (DSM). Highlights Spatial distribution of soil classes in Iran can be predicted using machine learning (ML) algorithms. The synthetic minority oversampling technique overcomes the drawback of imbalanced and highly biased soil legacy data. When combining a random forest model with synthetic sampling strategies the prediction accuracy of the soil model improves significantly. The resulting new soil map of Iran has a much higher spatial resolution compared to existing maps and displays new soil classes that have not yet been mapped in Iran.

Beschreibung: Alexander von Humboldt‐Stiftung http://dx.doi.org/10.13039/100005156

Beschreibung: German Research Foundation http://dx.doi.org/10.13039/501100001659

Beschreibung: Soil and Water Research Institute, Agricultural Research, Education and Extension Organization, Karaj, Iran

Schlagwort(e): 631.4 ; covariates ; imbalanced data ; machine learning ; random forest ; soil legacy data

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Impact of biochar on nutrient supply, crop yield and microbial respiration on sandy soils of northern Germany (2021)

Knoblauch, Christian ; Priyadarshani, S.H. Renuka ; Haefele, Stephan M. ; [weitere]

Blackwell Publishing Ltd | Oxford, UK

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Publikationsdatum: 2021-06-16

Beschreibung: The application of biochar to agricultural soils to increase nutrient availability, crop production and carbon sequestration has gained increasing interest but data from field experiments on temperate, marginal soils are still under‐represented. In the current study, biochar, produced from organic residues (digestates) from a biogas plant, was applied with and without digestates at low (3.4 t ha−1) and intermediate (17.1 t ha−1) rates to two acidic and sandy soils in northern Germany that are used for corn (Zea mays L.) production. Soil nutrient availability, crop yields, microbial biomass and carbon dioxide (CO2) emissions from heterotrophic respiration were measured over two consecutive years. The effects of biochar application depended on the intrinsic properties of the two tested soils and the biochar application rates. Although the soils at the fallow site, with initially low nutrient concentrations, showed a significant increase in pH, soil nutrients and crop yield after low biochar application rates, a similar response was found at the cornfield site only after application of substantially larger amounts of biochar. The effect of a single dose of biochar at the beginning of the experiment diminished over time but was still detectable after 2 years. Whereas plant available nutrient concentrations increased after biochar application, the availability of potentially phytotoxic trace elements (Zn, Pb, Cd, Cr) decreased significantly, and although slight increases in microbial biomass carbon and heterotrophic CO2 fluxes were observed after biochar application, they were mostly not significant. The results indicate that the application of relatively small amounts of biochar could have positive effects on plant available nutrients and crop yields of marginal arable soils and may decrease the need for mineral fertilizers while simultaneously increasing the sequestration of soil organic carbon. Highlights A low rate of biochar increased plant available nutrients and crop yield on marginal soils. Biochar application reduced the availability of potentially harmful trace elements. Heterotrophic respiration showed no clear response to biochar application. Biochar application may reduce fertilizer need and increase carbon sequestration on marginal soils.

Beschreibung: German Academic Exchange Service http://dx.doi.org/10.13039/501100001655

Beschreibung: Institute Strategic Programme grants, “Soils to Nutrition”

Schlagwort(e): 631.4 ; black carbon ; carbon sequestration ; corn ; digestate ; heterotrophic respiration ; marginal soils ; microbial biomass

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Self‐stated recovery from flooding: Empirical results from a survey in Central Vietnam (2021)

Hudson, Paul ; Pham, My ; Hagedoorn, Liselotte ; [weitere]

Blackwell Publishing Ltd | Oxford, UK

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Publikationsdatum: 2021-06-27

Beschreibung: Social inequalities lead to flood resilience inequalities across social groups, a topic that requires improved documentation and understanding. The objective of this paper is to attend to these differences by investigating self‐stated flood recovery across genders in Vietnam as a conceptual replication of earlier results from Germany. This study employs a regression‐based analysis of 1,010 respondents divided between a rural coastal and an urban community in Thua Thien‐Hue province. The results highlight an important set of recovery process‐related variables. The set of relevant variables is similar across genders in terms of inclusion and influence, and includes age, social capital, internal and external support after a flood, perceived severity of previous flood impacts, and the perception of stress‐resilience. However, women were affected more heavily by flooding in terms of longer recovery times, which should be accounted for in risk management. Overall, the studied variables perform similarly in Vietnam and Germany. This study, therefore, conceptually replicates previous results suggesting that women display slightly slower recovery levels as well as that psychological variables influence recovery rates more than adverse flood impacts. This provides an indication of the results' potentially robust nature due to the different socio‐environmental contexts in Germany and Vietnam.

Schlagwort(e): 333.7 ; flood recovery ; resilience ; societal equity ; vulnerability

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The potential of ryegrass as cover crop to reduce soil N2O emissions and increase the population size of denitrifying bacteria (2021)

Wang, Haitao ; Beule, Lukas ; Zang, Huadong ; [weitere]

Blackwell Publishing Ltd | Oxford, UK

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Publikationsdatum: 2021-07-05

Beschreibung: Nitrogen (N) fertilization is the major contributor to nitrous oxide (N2O) emissions from agricultural soil, especially in post‐harvest seasons. This study was carried out to investigate whether ryegrass serving as cover crop affects soil N2O emissions and denitrifier community size. A microcosm experiment was conducted with soil planted with perennial ryegrass (Lolium perenne L.) and bare soil, each with four levels of N fertilizer (0, 5, 10 and 20 g N m−2; applied as calcium ammonium nitrate). The closed‐chamber approach was used to measure soil N2O fluxes. Real‐time PCR was used to estimate the biomass of bacteria and fungi and the abundance of genes involved in denitrification in soil. The results showed that the presence of ryegrass decreased the nitrate content in soil. Cumulative N2O emissions of soil with grass were lower than in bare soil at 5 and 10 g N m−2. Fertilization levels did not affect the abundance of soil bacteria and fungi. Soil with grass showed greater abundances of bacteria and fungi, as well as microorganisms carrying narG, napA, nirK, nirS and nosZ clade I genes. It is concluded that ryegrass serving as a cover crop holds the potential to mitigate soil N2O emissions in soils with moderate or high NO3− concentrations. This highlights the importance of cover crops for the reduction of N2O emissions from soil, particularly following N fertilization. Future research should explore the full potential of ryegrass to reduce soil N2O emissions under field conditions as well as in different soils. Highlights This study was to investigate whether ryegrass serving as cover crop affects soil N2O emissions and denitrifier community size; Plant reduced soil N substrates on one side, but their root exudates stimulated denitrification on the other side; N2O emissions were lower in soil with grass than bare soil at medium fertilizer levels, and growing grass stimulated the proliferation of almost all the denitrifying bacteria except nosZ clade II; Ryegrass serving as a cover crop holds the potential to mitigate soil N2O emissions.

Beschreibung: China Scholarship Council http://dx.doi.org/10.13039/501100004543

Beschreibung: The National Science Project for University of Anhui Province

Schlagwort(e): 551.9 ; 631.4 ; denitrification ; perennial ryegrass (Lolium perenne L.) ; soil bacteria ; soil CO2 emissions ; soil N2O emissions

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ogs5py: A Python‐API for the OpenGeoSys 5 Scientific Modeling Package (2021)

Müller, Sebastian ; Zech, Alraune ; Heße, Falk

Blackwell Publishing Ltd | Malden, US

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Publikationsdatum: 2021-07-04

Beschreibung: High‐performance numerical codes are an indispensable tool for hydrogeologists when modeling subsurface flow and transport systems. But as they are written in compiled languages, like C/C++ or Fortran, established software packages are rarely user‐friendly, limiting a wider adoption of such tools. OpenGeoSys (OGS), an open‐source, finite‐element solver for thermo‐hydro‐mechanical–chemical processes in porous and fractured media, is no exception. Graphical user interfaces may increase usability, but do so at a dramatic reduction of flexibility and are difficult or impossible to integrate into a larger workflow. Python offers an optimal trade‐off between these goals by providing a highly flexible, yet comparatively user‐friendly environment for software applications. Hence, we introduce ogs5py, a Python‐API for the OpenGeoSys 5 scientific modeling package. It provides a fully Python‐based representation of an OGS project, a large array of convenience functions for users to interact with OGS and connects OGS to the scientific and computational environment of Python.

Beschreibung: German Federal Environmental Foundation http://dx.doi.org/10.13039/100007636

Beschreibung: Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659

Schlagwort(e): 551.49 ; hydrogeology ; subsurface flow ; modeling ; software

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High‐Resolution Integrated Transport Model for Studying Surface Water–Groundwater Interaction (2021)

Broecker, Tabea ; Sobhi Gollo, Vahid ; Fox, Aryeh ; [weitere]

Blackwell Publishing Ltd | Malden, US

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Publikationsdatum: 2021-06-27

Beschreibung: Transport processes that lead to exchange of mass between surface water and groundwater play a significant role for the ecological functioning of aquatic systems, for hydrological processes and for biogeochemical transformations. In this study, we present a novel integral modeling approach for flow and transport at the sediment–water interface. The model allows us to simultaneously simulate turbulent surface and subsurface flow and transport with the same conceptual approach. For this purpose, a conservative transport equation was implemented to an existing approach that uses an extended version of the Navier–Stokes equations. Based on previous flume studies which investigated the spreading of a dye tracer under neutral, losing and gaining flow conditions the new solver is validated. Tracer distributions of the experiments are in close agreement with the simulations. The simulated flow paths are significantly affected by in‐ and outflowing groundwater flow. The highest velocities within the sediment are found for losing condition, which leads to shorter residence times compared to neutral and gaining conditions. The largest extent of the hyporheic exchange flow is observed under neutral condition. The new solver can be used for further examinations of cases that are not suitable for the conventional coupled models, for example, if Reynolds numbers are larger than 10. Moreover, results gained with the integral solver provide high‐resolution information on pressure and velocity distributions at the rippled streambed, which can be used to improve flow predictions. This includes the extent of hyporheic exchange under varying ambient groundwater flow conditions.

Beschreibung: Technische Universität Berlin, Germany

Beschreibung: German Research Foundation http://dx.doi.org/10.13039/501100001659

Schlagwort(e): 551.4 ; aquatic systems ; sediment-water interface ; transport model

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Iron isotope fractionation in soil and graminaceous crops after 100 years of liming in the long‐term agricultural experimental site at Berlin‐Dahlem, Germany (2021)

Wu, Bei ; Wang, Yi ; Berns, Anne E. ; [weitere]

Blackwell Publishing Ltd | Oxford, UK

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Publikationsdatum: 2021-07-05

Beschreibung: Sustainable arable cropping relies on repeated liming. Yet, the associated increase in soil pH can reduce the availability of iron (Fe) to plants. We hypothesized that repeated liming, but not pedogenic processes such as lessivage (i.e., translocation of clay particles), alters the Fe cycle in Luvisol soil, thereby affecting Fe isotope composition in soils and crops. Hence, we analysed Fe concentrations and isotope compositions in soil profiles and winter rye from the long‐term agricultural experimental site in Berlin‐Dahlem, Germany, where a controlled liming trial with three field replicates per treatment has been conducted on Albic Luvisols since 1923. Heterogeneity in subsoil was observed at this site for Fe concentration but not for Fe isotope composition. Lessivage had not affected Fe isotope composition in the soil profiles. The results also showed that almost 100 years of liming lowered the concentration of the HCl‐extractable Fe that was potentially available for plant uptake in the surface soil (0–15 cm) from 1.03 (standard error (SE) 0.03) to 0.94 (SE 0.01) g kg−1. This HCl‐extractable Fe pool contained isotopically lighter Fe (δ56Fe = −0.05 to −0.29‰) than the bulk soil (δ56Fe = −0.08 to 0.08‰). However, its Fe isotope composition was not altered by the long‐term lime application. Liming resulted in relatively lower Fe concentrations in the roots of winter rye. In addition, liming led to a heavier Fe isotope composition of the whole plants compared with those grown in the non‐limed plots (δ56FeWholePlant_ + Lime = −0.12‰, SE 0.03 vs. δ56FeWholePlant_‐Lime = −0.21‰, SE 0.01). This suggests that the elevated soil pH (increased by one unit due to liming) promoted the Fe uptake strategy through complexation of Fe(III) from the rhizosphere, which favoured heavier Fe isotopes. Overall, the present study showed that liming and a related increase in pH did not affect the Fe isotope compositions of the soil, but may influence the Fe isotope composition of plants grown in the soil if they alter their Fe uptake strategy upon the change of Fe availability. Highlights Fe concentrations and stocks, but not Fe isotope compositions, were more heterogeneous in subsoil than in topsoil. Translocation of clay minerals did not result in Fe isotope fractionation in the soil profile of a Luvisol. Liming decreased Fe availability in topsoil, but did not affect its δ56Fe values. Uptake of heavier Fe isotopes by graminaceous crops was more pronounced at elevated pH.

Beschreibung: Bundesministerium für Bildung und Forschung http://dx.doi.org/10.13039/501100002347

Schlagwort(e): 551.9 ; liming ; plant‐available Fe pool in soil ; winter rye ; δ56Fe

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Overview of the mating systems of Crustacea (2020)

Palaoro, Alexandre V. ; Beermann, Jan

Oxford University Press

In: EPIC3The Natural History of the Crustacea, Vol. 6: Reproductive Biology, New York, U.S.A., Oxford University Press, 30 p., pp. 277-306, ISBN: 9780190688554

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Publikationsdatum: 2021-02-24

Beschreibung: Due to an exceptional variety of habitats, body plans, and lifestyles, crustaceans exhibit a wide array of mating systems. Some groups engage in simple, pure- search polygamous systems in which males usually search for receptive females. In other groups, males defend valuable resources to attract and/ or guard females to ensure paternity. Some species have developed highly complex systems of harem defense polygyny and monogamy, even cases of sub- and eusociality are reported. The expression of mating systems does not seem to be uniformly correlated to taxonomic affiliation, but is rather diverse within certain groups, suggesting that the evolution of mating systems is largely facilitated by the lifestyle of the species. Despite the broad range of mating systems in crustaceans, and although some groups have been studied comparably well, there remains a lack of knowledge about the behavioral and sexual biology of many species. In the light of the high diversity of lifestyles, mating systems, and habitats of certain groups, crustacean species would be ideal models to unravel the evolution of reproductive strategies and social behaviors.

Repository-Name: EPIC Alfred Wegener Institut

Materialart: Inbook , peerRev

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The ‘Flood Resilience Rose’: A management tool to promote transformation towards flood resilience (2021)

Karrasch, Leena ; Restemeyer, Britta ; Klenke, Thomas

Blackwell Publishing Ltd | Oxford, UK

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Publikationsdatum: 2021-09-29

Beschreibung: Coping with the growing impacts of flooding in EU countries, a paradigm shift in flood management can be observed, moving from safety‐based towards risk‐based approaches and holistic perspectives. Flood resilience is a common denominator of most of the approaches. In this article, we present the ‘Flood Resilience Rose’ (FRR), a management tool to promote harmonised action towards flood resilience in European regions and beyond. The FRR is a result of a two‐step process. First, based on scientific concepts as well as analysis of relevant policy documents, we identified three ‘levels of operation’. The first level refers to the EU Floods Directive and an extended multi‐layer safety approach, comprising the four different layers of protection, prevention, preparedness and recovery, and related measures to be taken. This level is not independent but depends both on the institutional (second level) and the wider (third level) context. Second, we used surveys, semi‐structured interviews and group discussions during workshops with experts from Belgium, Denmark, Germany, the Netherlands and the United Kingdom to validate the definitions and the FRR's practical relevance. The presented FRR is thus the result of rigorous theoretical and practical consideration and provides a tool capable to strengthen flood risk management practice.

Beschreibung: European Regional Development Fund http://dx.doi.org/10.13039/501100008530

Schlagwort(e): 551.48 ; flood defence measures ; governance and institutions ; integrated flood risk management ; resilience

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Making massive stars in the Galactic Centre via accretion on to low-mass stars within an accretion disc (2020)

Davies, Melvyn B ; Lin, Doug N C

Oxford University Press

In: Monthly Notices of the Royal Astronomical Society. 2020; 498(3): 3452-3456. Published 2020 Aug 27. doi: 10.1093/mnras/staa2590.

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Publikationsdatum: 2020-08-27

Beschreibung: The origin of the population of very massive stars observed within ∼0.4 pc of the supermassive black hole in the Galactic Centre is a mystery. Tidal forces from the black hole would likely inhibit in situ star formation whilst the youth of the massive stars would seem to exclude formation elsewhere followed by transportation (somehow) into the Galactic Centre. Here, we consider a third way to produce these massive stars from the lower mass stars contained in the nuclear stellar cluster which surrounds the supermassive black hole. A passing gas cloud can be tidally shredded by the supermassive black hole forming an accretion disc around the black hole. Stars embedded within this accretion disc will accrete gas from the disc via Bondi–Hoyle accretion, where the accretion rate on to a star, $dot{M}_star propto M_star ^2$. This super-exponential growth of accretion can lead to a steep increase in stellar masses, reaching the required 40–50 M⊙ in some cases. The mass growth rate depends sensitively on the stellar orbital eccentricities and their inclinations. The evolution of the orbital inclinations and/or their eccentricities as stars are trapped by the disc, and their orbits are circularized, will increase the number of massive stars produced. Thus accretion on to low-mass stars can lead to a top heavy stellar mass function in the Galactic Centre and other galactic nuclei. The massive stars produced will pollute the environment via supernova explosions and potentially produce compact binaries whose mergers may be detectable by the LIGO–VIRGO gravitational waves observatories.

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Thema: Physik

Publiziert von Oxford University Press im Namen von The Royal Astronomical Society.

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The observational impact of dust trapping in self-gravitating discs (2020)

Cadman, James ; Hall, Cassandra ; Rice, Ken ; [weitere]

Oxford University Press

In: Monthly Notices of the Royal Astronomical Society. 2020; 498(3): 4256-4271. Published 2020 Aug 27. doi: 10.1093/mnras/staa2596.

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Publikationsdatum: 2020-08-27

Beschreibung: We present a 3D semi-analytical model of self-gravitating discs, and include a prescription for dust trapping in the disc spiral arms. Using Monte Carlo radiative transfer, we produce synthetic ALMA (Atacama Large Millimeter/submillimeter Array) observations of these discs. In doing so, we demonstrate that our model is capable of producing observational predictions, and able to model real image data of potentially self-gravitating discs. For a disc to generate spiral structure that would be observable with ALMA requires that the disc’s dust mass budget is dominated by millimetre- and centimetre-sized grains. Discs in which grains have grown to the grain fragmentation threshold may satisfy this criterion; thus, we predict that signatures of gravitational instability may be detectable in discs of lower mass than has previously been suggested. For example, we find that discs with disc-to-star mass ratios as low as 0.10 are capable of driving observable spiral arms. Substructure becomes challenging to detect in discs where no grain growth has occurred or in which grain growth has proceeded well beyond the grain fragmentation threshold. We demonstrate how we can use our model to retrieve information about dust trapping and grain growth through multiwavelength observations of discs, and using estimates of the opacity spectral index. Applying our disc model to the Elias 27, WaOph 6, and IM Lup systems, we find gravitational instability to be a plausible explanation for the observed substructure in all three discs, if sufficient grain growth has indeed occurred.

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Thema: Physik

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Factories of CO-dark gas: molecular clouds with limited star formation efficiencies by far-ultraviolet feedback (2020)

Inoguchi, Mutsuko ; Hosokawa, Takashi ; Mineshige, Shin ; [weitere]

Oxford University Press

In: Monthly Notices of the Royal Astronomical Society. 2020; 497(4): 5061-5075. Published 2020 Aug 27. doi: 10.1093/mnras/staa2022.

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Beschreibung: The star formation in molecular clouds is inefficient. The ionizing extreme-ultraviolet radiation (hν ≥ 13.6 eV) from young clusters has been considered as a primary feedback effect to limit the star formation efficiency (SFE). Here, we focus on the effects of stellar far-ultraviolet (FUV) radiation (6 eV ≤ hν ≤ 13.6 eV) during the cloud disruption stage. The FUV radiation may further reduce the SFE via photoelectric heating, and it also affects the chemical states of the gas that is not converted to stars (‘cloud remnants’) via photodissociation of molecules. We have developed a one-dimensional semi-analytical model that follows the evolution of both the thermal and chemical structure of a photodissociation region (PDR) during the dynamical expansion of an H ii region. We investigate how the FUV feedback limits the SFE, supposing that the star formation is quenched in the PDR where the temperature is above a threshold value (e.g. 100 K). Our model predicts that the FUV feedback contributes to reduce the SFEs for massive (Mcl ≳ 105 M⊙) clouds with low surface densities ($Sigma _{ m cl}lesssim 100~{ m M}_odot , { m pc}^{-2}$). Moreover, we show that a large part of the H2 molecular gas contained in the cloud remnants should be ‘CO-dark’ under the FUV feedback for a wide range of cloud properties. Therefore, the dispersed molecular clouds are potential factories of CO-dark gas, which returns into the cycle of the interstellar medium.

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PS1-STRM: Neural network source classification and photometric redshift catalogue for PS1 3π DR1 (2020)

Beck, Róbert ; Szapudi, István ; Flewelling, Heather ; [weitere]

Oxford University Press

In: Monthly Notices of the Royal Astronomical Society. 2020; Published 2020 Aug 31. doi: 10.1093/mnras/staa2587. [early online release]

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Publikationsdatum: 2020-08-31

Beschreibung: The Pan-STARRS1 (PS1) 3π survey is a comprehensive optical imaging survey of three quarters of the sky in the grizy broad-band photometric filters. We present the methodology used in assembling the source classification and photometric redshift (photo-z) catalogue for PS1 3π Data Release 1, titled Pan-STARRS1 Source Types and Redshifts with Machine learning (PS1-STRM). For both main data products, we use neural network architectures, trained on a compilation of public spectroscopic measurements that has been cross-matched with PS1 sources. We quantify the parameter space coverage of our training data set, and flag extrapolation using self-organizing maps. We perform a Monte-Carlo sampling of the photometry to estimate photo-z uncertainty. The final catalogue contains 2,902,054,648 objects. On our validation data set, for non-extrapolated sources, we achieve an overall classification accuracy of $98.1\%$ for galaxies, $97.8\%$ for stars, and $96.6\%$ for quasars. Regarding the galaxy photo-z estimation, we attain an overall bias of =0.0005, a standard deviation of σ(Δznorm) = 0.0322, a median absolute deviation of MAD(Δznorm) = 0.0161, and an outlier fraction of $Pleft(|Delta z_{mathrm{norm}}|〉0.15 ight)=1.89\%$. The catalogue will be made available as a high-level science product via the Mikulski Archive for Space Telescopes.

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Short Electric Waves (1923)

Nichols, E. F. ; Tear, J. D.

American Physical Society

In: Physical Review, Series II. 1923; 21(6): 587-610. Published 1923 Jun 01. doi: 10.1103/physrev.21.587.

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Publikationsdatum: 1923-06-01

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Thema: Physik

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Ionization Potentials of Argon, Nitrogen, Carbon Monoxide, Helium, Hydrogen and Mercury and Iodine Vapors (1920)

Found, Clifton G.

American Physical Society

In: Physical Review, Series II. 1920; 16(1): 41-53. Published 1920 Jul 01. doi: 10.1103/physrev.16.41.

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Thema: Physik

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Note on paper by C. V. Kent on the Optical Constants of Liquid Alloys (1920)

Wilson, H. A.

American Physical Society

In: Physical Review, Series II. 1920; 15(4): 317-317. Published 1920 Apr 01. doi: 10.1103/physrev.15.317.

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On the Principle of Combination and Stokes' Law in the X-ray Series (1922)

Coster, D.

American Physical Society

In: Physical Review, Series II. 1922; 19(1): 20-23. Published 1922 Jan 01. doi: 10.1103/physrev.19.20.

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Secondary Electron Emission from Copper Surfaces (1921)

Barber, I. Garnett

American Physical Society

In: Physical Review, Series II. 1921; 17(3): 322-338. Published 1921 Mar 01. doi: 10.1103/physrev.17.322.

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Publikationsdatum: 1921-03-01

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Variation of Diathermancy with the Temperature of the Radiating Source (1923)

Brown, S. Leroy

American Physical Society

In: Physical Review, Series II. 1923; 21(1): 103-106. Published 1923 Jan 01. doi: 10.1103/physrev.21.103.

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Thermal Conductivity of Some Wearing Materials (1921)

Rood, Emily S.

American Physical Society

In: Physical Review, Series II. 1921; 18(5): 356-361. Published 1921 Nov 01. doi: 10.1103/physrev.18.356.

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The Contact Electricity of Solid Dielectrics (1923)

Richards, Harold F.

American Physical Society

In: Physical Review, Series II. 1923; 22(2): 122-133. Published 1923 Aug 01. doi: 10.1103/physrev.22.122.

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A Mathematical Treatment of the Electric Conductivity and Capacity of Disperse Systems I. The Electric Conductivity of a Suspension of Homogeneous Spheroids (1924)

Fricke, Hugo

American Physical Society

In: Physical Review, Series II. 1924; 24(5): 575-587. Published 1924 Nov 01. doi: 10.1103/physrev.24.575.

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"Thalofide Cell"—a New Photo-Electric Substance (1920)

Case, T. W.

American Physical Society

In: Physical Review, Series II. 1920; 15(4): 289-292. Published 1920 Apr 01. doi: 10.1103/physrev.15.289.

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The Laws of Absorption of X-Rays. (1921)

Richtmyer, F. K.

American Physical Society

In: Physical Review, Series II. 1921; 18(1): 13-30. Published 1921 Jul 01. doi: 10.1103/physrev.18.13.

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The Effect of A Uniform Magnetic Field on the Motion of Electrons Between Coaxial Cylinders. (1921)

Hull, Albert W.

American Physical Society

In: Physical Review, Series II. 1921; 18(1): 31-57. Published 1921 Jul 01. doi: 10.1103/physrev.18.31.

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The Scattering of low Speed Electrons by Platinum and Magnesium (1923)

Davisson, C. ; Kunsman, C. H.

American Physical Society

In: Physical Review, Series II. 1923; 22(3): 242-258. Published 1923 Sep 01. doi: 10.1103/physrev.22.242.

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Quantum Emission Phenomena in Radiation (1920)

Webster, David L.

American Physical Society

In: Physical Review, Series II. 1920; 16(1): 31-40. Published 1920 Jul 01. doi: 10.1103/physrev.16.31.

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Properties of Rochelle Salt Related to the Piezo-electric Effect (1922)

Valasek, Joseph

American Physical Society

In: Physical Review, Series II. 1922; 20(6): 639-664. Published 1922 Dec 01. doi: 10.1103/physrev.20.639.

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The Effect of Space Charge and Initial Velocities on the Potential Distribution and Thermionic Current between Parallel Plane Electrodes (1923)

Langmuir, Irving

American Physical Society

In: Physical Review, Series II. 1923; 21(4): 419-435. Published 1923 Apr 01. doi: 10.1103/physrev.21.419.

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Phenomena in Oxide-Coated Filament Electron Tubes (1920)

Arnold., H. D.

American Physical Society

In: Physical Review, Series II. 1920; 16(1): 70-82. Published 1920 Jul 01. doi: 10.1103/physrev.16.70.

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The Dilemma of the Helium Atom (1922)

van Vleck, John H.

American Physical Society

In: Physical Review, Series II. 1922; 19(4): 419-420. Published 1922 Apr 01. doi: 10.1103/physrev.19.419.

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Coefficients of Viscosity and Slip of Corbon Dioxide (1924)

Eglin, James M.

American Physical Society

In: Physical Review, Series II. 1924; 23(2): 286-286. Published 1924 Feb 01. doi: 10.1103/physrev.23.286.2.

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An Experimental Investigation of the Dispersion of a Limited Wave Train (1922)

Solt, Irvin H.

American Physical Society

In: Physical Review, Series II. 1922; 20(6): 513-525. Published 1922 Dec 01. doi: 10.1103/physrev.20.513.

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Experiments on the Sign of the Electric Charge Assumed by a Metal Immersed in a Liquid (1923)

Kleeman, Richard D. ; Fredrickson, William

American Physical Society

In: Physical Review, Series II. 1923; 22(2): 134-136. Published 1923 Aug 01. doi: 10.1103/physrev.22.134.

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The Extension of the X-ray-Doublet Laws into the Field of Optics (1924)

Bowen, I. S. ; Millikan, R. A.

American Physical Society

In: Physical Review, Series II. 1924; 24(3): 209-222. Published 1924 Sep 01. doi: 10.1103/physrev.24.209.

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The Dynamical Theory of the Bridge of a Certain Class of Stringed Instrumentsd (1923)

Kar, K. C.

American Physical Society

In: Physical Review, Series II. 1923; 21(6): 695-698. Published 1923 Jun 01. doi: 10.1103/physrev.21.695.

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A Method for the Neutralization of Electron Space Charge by Positive Ionization at Very Low Gas Pressures (1923)

Kingdon, K. H.

American Physical Society

In: Physical Review, Series II. 1923; 21(4): 408-418. Published 1923 Apr 01. doi: 10.1103/physrev.21.408.

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Effect of Tension on Change of Resistance and Thermoelectromotive Force by Transverse Magnetization (1923)

Smith, Alpheus W.

American Physical Society

In: Physical Review, Series II. 1923; 22(1): 58-65. Published 1923 Jul 01. doi: 10.1103/physrev.22.58.

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Acoustical Power of Certain Sound Sources in Absolute Units (1923)

Sabine, Paul E.

American Physical Society

In: Physical Review, Series II. 1923; 22(3): 303-312. Published 1923 Sep 01. doi: 10.1103/physrev.22.303.

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The Hall Effect and Specific Resistance of Cathodically Deposited Films of Gold (1924)

Mackeown, S. S.

American Physical Society

In: Physical Review, Series II. 1924; 23(1): 85-93. Published 1924 Jan 01. doi: 10.1103/physrev.23.85.

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Theory of the Electric Arc (1923)

Compton, K. T.

American Physical Society

In: Physical Review, Series II. 1923; 21(3): 266-291. Published 1923 Mar 01. doi: 10.1103/physrev.21.266.

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Hall Effect and Specific Resistance of Evaporated Films of Silver, Copper and Iron (1923)

Steinberg, J. C.

American Physical Society

In: Physical Review, Series II. 1923; 21(1): 22-29. Published 1923 Jan 01. doi: 10.1103/physrev.21.22.

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Effect of a Retarding Plate on White Light Interferometer Fringes (1924)

Sethi, Nihal Karan

American Physical Society

In: Physical Review, Series II. 1924; 23(1): 69-74. Published 1924 Jan 01. doi: 10.1103/physrev.23.69.

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Free Convection of Heat in Liquids (1924)

Nelson, Roy A.

American Physical Society

In: Physical Review, Series II. 1924; 23(1): 94-103. Published 1924 Jan 01. doi: 10.1103/physrev.23.94.

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The Power Loss in Condensers with Liquid Dielectrics (1924)

McDowell, Louise S.

American Physical Society

In: Physical Review, Series II. 1924; 23(4): 507-519. Published 1924 Apr 01. doi: 10.1103/physrev.23.507.

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The Effect of Temperature on the Luminosity of Radium Compounds (1924)

Rodman, Jessie A.

American Physical Society

In: Physical Review, Series II. 1924; 23(4): 478-487. Published 1924 Apr 01. doi: 10.1103/physrev.23.478.

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The Photoluminescence of Flames. II (1924)

Nichols, E. L. ; Howes, H. L.

American Physical Society

In: Physical Review, Series II. 1924; 23(4): 472-477. Published 1924 Apr 01. doi: 10.1103/physrev.23.472.

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Characteristics of Iron in High Frequency Rotating Magnetic Fields (1924)

Tonks, Lewi

American Physical Society

In: Physical Review, Series II. 1924; 23(2): 221-238. Published 1924 Feb 01. doi: 10.1103/physrev.23.221.

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The Variation of Thermionic Emission with Temperature and the Concentration of Free Electrons within Conductors (1924)

Waterman, A. T.

American Physical Society

In: Physical Review, Series II. 1924; 24(4): 366-376. Published 1924 Oct 01. doi: 10.1103/physrev.24.366.

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Some Molecular Absorption Spectra of Hydrogen Cyanide (1924)

Barker, E. F.

American Physical Society

In: Physical Review, Series II. 1924; 23(2): 200-204. Published 1924 Feb 01. doi: 10.1103/physrev.23.200.

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The Electrical Properties of Flames Containing Salt Vapors for High Frequency Alternating Currents (1924)

Bryan, A. B.

American Physical Society

In: Physical Review, Series II. 1924; 23(2): 189-194. Published 1924 Feb 01. doi: 10.1103/physrev.23.189.

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Minutes of the Berkeley Meeting, March 1, 1924. (1924)

Anonymous,

American Physical Society

In: Physical Review, Series II. 1924; 23(5): 662-666. Published 1924 May 01. doi: 10.1103/physrev.23.662.

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Direction of Ejection of Photo-Electrons by Polarized X-rays (1924)

Bubb, Frank W.

American Physical Society

In: Physical Review, Series II. 1924; 23(2): 137-143. Published 1924 Feb 01. doi: 10.1103/physrev.23.137.

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On Methods of Varying the Sensitiveness of Ballistic Galvanometers (1924)

Masius, Morton

American Physical Society

In: Physical Review, Series II. 1924; 23(5): 649-654. Published 1924 May 01. doi: 10.1103/physrev.23.649.

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Oblique Scattering of Light in Gases and Liquids (1924)

Ganesan, A. S.

American Physical Society

In: Physical Review, Series II. 1924; 23(1): 63-68. Published 1924 Jan 01. doi: 10.1103/physrev.23.63.

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The Current-Voltage Relation in the Corona (1924)

Fazel, C. S. ; Parsons, S. R.

American Physical Society

In: Physical Review, Series II. 1924; 23(5): 598-607. Published 1924 May 01. doi: 10.1103/physrev.23.598.

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Book Reviews (1924)

Anonymous,

American Physical Society

In: Physical Review, Series II. 1924; 23(5): 661-661. Published 1924 May 01. doi: 10.1103/physrev.23.661.

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79

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Corpuscular Theory of the Distribution of the Recoil Electrons Produced by Polarized X-rays (1924)

Jauncey, G. E. M.

American Physical Society

In: Physical Review, Series II. 1924; 23(5): 580-582. Published 1924 May 01. doi: 10.1103/physrev.23.580.

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Formulas for the Amplification Constant for Three-Element Tubes in which the Diameter of Grid Wires is Large Compared to the Spacing (1924)

Vogdes, F. B. ; Elder, Frank R.

American Physical Society

In: Physical Review, Series II. 1924; 24(6): 683-689. Published 1924 Dec 01. doi: 10.1103/physrev.24.683.

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81

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Quantitative Theory of the Influence Electrostatic Generator (1924)

Simon, Alfred W.

American Physical Society

In: Physical Review, Series II. 1924; 24(6): 690-696. Published 1924 Dec 01. doi: 10.1103/physrev.24.690.

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82

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The Mobility of Actinium Active Deposit Ions (1924)

Erikson, Henry A.

American Physical Society

In: Physical Review, Series II. 1924; 24(6): 622-626. Published 1924 Dec 01. doi: 10.1103/physrev.24.622.

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83

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Proof of the Invariance under the Lorentz Transformation of the Equation of Motion of the Electron (1924)

Page, Leigh

American Physical Society

In: Physical Review, Series II. 1924; 24(6): 627-630. Published 1924 Dec 01. doi: 10.1103/physrev.24.627.

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84

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Index of Refraction of Calcite for X-rays (1924)

Hatley, C. C.

American Physical Society

In: Physical Review, Series II. 1924; 24(5): 486-494. Published 1924 Nov 01. doi: 10.1103/physrev.24.486.

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85

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Hall Effect in a Conductor due to its Own Magnetic Field (1924)

van B. Roberts, W.

American Physical Society

In: Physical Review, Series II. 1924; 24(5): 532-543. Published 1924 Nov 01. doi: 10.1103/physrev.24.532.

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Publikationsdatum: 1924-11-01

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86

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A Method for the Estimation of the Average Life of Excited Mercury Atoms (1924)

Turner, Louis A.

American Physical Society

In: Physical Review, Series II. 1924; 23(4): 464-471. Published 1924 Apr 01. doi: 10.1103/physrev.23.464.

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Publikationsdatum: 1924-04-01

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87

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Torque on a Cylindrical Magnet through which a Current is Passing (1924)

Zeleny, John ; Page, Leigh

American Physical Society

In: Physical Review, Series II. 1924; 24(5): 544-559. Published 1924 Nov 01. doi: 10.1103/physrev.24.544.

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88

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The Optical Constants of Certain Liquids for Short Electric Waves (1923)

Tear, J. D.

American Physical Society

In: Physical Review, Series II. 1923; 21(6): 611-622. Published 1923 Jun 01. doi: 10.1103/physrev.21.611.

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Publikationsdatum: 1923-06-01

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89

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A New Precision X-ray Spectrometer (1924)

Soller, Walter

American Physical Society

In: Physical Review, Series II. 1924; 24(2): 158-167. Published 1924 Aug 01. doi: 10.1103/physrev.24.158.

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Publikationsdatum: 1924-08-01

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90

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The Dependence of the Loudness of a Complex Sound upon the Energy in the Various Frequency Regions of the Sound (1924)

Fletcher, H. ; Steinberg, J. C.

American Physical Society

In: Physical Review, Series II. 1924; 24(3): 306-317. Published 1924 Sep 01. doi: 10.1103/physrev.24.306.

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Publikationsdatum: 1924-09-01

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91

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Theoretical Interpretation of the Polarization Experiment of Wood and Ellett (1924)

Eldridge, John A.

American Physical Society

In: Physical Review, Series II. 1924; 24(3): 234-242. Published 1924 Sep 01. doi: 10.1103/physrev.24.234.

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92

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Some Conspicuous Successes of the Bohr Atom and a Serious Difficulty (1924)

Millikan, R. A. ; Bowen, I. S.

American Physical Society

In: Physical Review, Series II. 1924; 24(3): 223-228. Published 1924 Sep 01. doi: 10.1103/physrev.24.223.

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93

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The Opacity of an Ionized Gas (1923)

Stewart, John Q.

American Physical Society

In: Physical Review, Series II. 1923; 22(4): 324-332. Published 1923 Oct 01. doi: 10.1103/physrev.22.324.

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94

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128th Meeting Stanford University, June 26, 1924 (1924)

Anonymous,

American Physical Society

In: Physical Review, Series II. 1924; 24(2): 204-208. Published 1924 Aug 01. doi: 10.1103/physrev.24.204.

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95

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The K and L Absorption and Emission Spectra of Tungsten (1924)

Crofutt, C. B.

American Physical Society

In: Physical Review, Series II. 1924; 24(1): 9-15. Published 1924 Jul 01. doi: 10.1103/physrev.24.9.

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Publikationsdatum: 1924-07-01

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96

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On the Thermodynamics of Thermal Transpiration and of the Thomson Effect (1923)

Kennard, E. H.

American Physical Society

In: Physical Review, Series II. 1923; 22(6): 617-621. Published 1923 Dec 01. doi: 10.1103/physrev.22.617.

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Publikationsdatum: 1923-12-01

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97

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The Photo-Electric Effect of Caesium Vapor (1923)

Kunz, Jakob ; Williams, E. H.

American Physical Society

In: Physical Review, Series II. 1923; 22(5): 456-460. Published 1923 Nov 01. doi: 10.1103/physrev.22.456.

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98

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The Absorption of Radiation by Multiply Periodic Orbits, and its Relation to the Correspondence Principle and the Rayleigh-Jeans Law. Part II. Calculation of Absorption by Multiply Periodic Orbits (1924)

van Vleck, J. H.

American Physical Society

In: Physical Review, Series II. 1924; 24(4): 347-365. Published 1924 Oct 01. doi: 10.1103/physrev.24.347.

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99

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The Radii of the Alkali and Halogen Ions and of the Atoms of Inert Gases (1923)

Davey, Wheeler P.

American Physical Society

In: Physical Review, Series II. 1923; 22(3): 211-220. Published 1923 Sep 01. doi: 10.1103/physrev.22.211.

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100

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Effect of Temperature on the Regular Reflection of X-rays from Aluminum Foil (1924)

Collins, E. H.

American Physical Society

In: Physical Review, Series II. 1924; 24(2): 152-157. Published 1924 Aug 01. doi: 10.1103/physrev.24.152.

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