ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics  (2)
  • Southern Apennines  (2)
  • 04. Solid Earth::04.07. Tectonophysics::04.07.99. General or miscellaneous  (1)
  • 1
    Publication Date: 2017-04-04
    Description: The Mercure earthquake (Mw 5.6) of September 9, 1998 and the associated aftershocks occurred in a small Pleistocene–Holocene continental basin of the Southern Apennines, in a region of low instrumental and moderate historical seismicity. Seismological, photogeological and field survey data were analyzed and integrated in order to identify the likely seismogenic structure, to depict its 3-D geometry and kinematics and to provide further constraints to the seismogenic potential of the rupture processes in the study area. The mainshock occurred at the NW edge of the seismic sequence (40.03°N and 15.95°) at a depth of 10.5± 1.5 km. The aftershocks volume was determined from the relocation of about 200 events (1.1=Ml=3.9) registered by local networks from September 10 to October 12, 1998. The relocation procedure was based on choosing P and S waves for all the events and the definition of ten 9-layers velocity models appropriate for the different stations. The kinematics of the seismogenic deformation was defined through the computation of 36 well-constrained focal mechanisms. The seismological and geological stress tensors were determined through inversion of focal mechanisms and fault slip data. Both of them resulted in the tensional type, with ENE–WSW and NE–SW trending σ3 axis, respectively. The map and the section distribution of the aftershocks sequence depicts an average NW–SE striking and 60° SW-dipping seismogenic volume. Most of the events (80%) were located at depths between 3 and 8 km in the footwall of the Mercure basin (MBB) boundary fault but along the possible down-dip continuation of a previously unidentified, N120°E striking and WSW-dipping, Holocene normal fault alignment, which extends from Castello Seluci to Piana Perretti and Timpa della Manca (CPST fault). A small percentage of events (10%) were located at depths between 10 and 12 km where the CPST seismogenic fault may detach. The reconstructed rupture area (RA) of the Mercure 1998 earthquake has an along-strike length (L) of about 9 km and a down-dip width (W) of about 9 km, yielding a total area of approximately 81 km2 . On the other hand, the L and W dimension of the entire individual seismogenic structure identified as responsible for the earthquake, e.g. the CPST fault, are about 19 and 12 km, respectively, with a consequent RA of about 230 km2 . This may imply a maximum magnitude (Mw) equal to 6.3 which lead us to compare the Mercure area, in terms of seismogenic hazard, to the adjacent Pollino-Castrovillari area where strong paleoseismological events are documented.
    Description: Published
    Description: 210–225
    Description: 3.2. Tettonica attiva
    Description: JCR Journal
    Description: reserved
    Keywords: Southern Apennines ; Stress-distribution ; Earthquake location ; Seismotectonics ; 04. Solid Earth::04.06. Seismology::04.06.01. Earthquake faults: properties and evolution
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Publication Date: 2017-04-04
    Description: We present a revision and a seismotectonic interpretation of deep crust strike–slip earthquake sequences that occurred in 1990– 1991 in the Southern Apennines (Potenza area). The revision is motivated by: i) the striking similarity to a seismic sequence that occurred in 2002 ∼140 km NNW, in an analogous tectonic context (Molise area), suggesting a common seismotectonic environment of regional importance; ii) the close proximity of such deep strike–slip seismicity with shallow extensional seismicity (Apennine area); and iii) the lack of knowledge about the mechanical properties of the crust that might justify the observed crustal seismicity. A comparison between the revised 1990–1991 earthquakes and the 2002 earthquakes, as well as the integration of seismological data with a rheological analysis offer new constraints on the regional seismotectonic context of crustal seismicity in the Southern Apennines. The seismological revision consists of a relocation of the aftershock sequences based on newly constrained velocity models. New focal mechanisms of the aftershocks are computed and the active state of stress is constrained via the use of a stress inversion technique. The relationships among the observed seismicity, the crustal structure of the Southern Apennines, and the rheological layering are analysed along a crustal section crossing southern Italy, by computing geotherms and two-mechanism (brittle frictional vs. ductile plastic strength) rheological profiles. The 1990–1991 seismicity is concentrated in a well-defined depth range (mostly between 15 and 23 km depths). This depth range corresponds to the upper pat of the middle crust underlying the Apulian sedimentary cover, in the footwall of the easternmost Apennine thrust system. The 3D distribution of the aftershocks, the fault kinematics, and the stress inversion indicate the activation of a right-lateral strike–slip fault striking N100°E under a stress field characterized by a sub-horizontal N142°-trending σ1 and a sub-horizontal N232°-trending σ3, very similar to the known stress field of the Gargano seismic zone in the Apulian foreland. The apparent anomalous depths of the earthquakes (N15 km) and the confinement within a relatively narrow depth range are explained by the crustal rheology, which consists of a strong brittle layer at mid crustal depths sandwiched between two plastic horizons. This articulated rheological stratification is typical of the central part of the Southern Apennine crust, where the Apulian crust is overthrusted by Apennine units. Both the Potenza 1990–1991 and the Molise 2002 seismic sequences can be interpreted to be due to crustal E–W fault zones within the Apulian crust inherited from previous tectonic phases and overthrusted by Apennine units during the Late Pliocene–Middle Pleistocene. The present strike–slip tectonic regime reactivated these fault zones and caused them to move with an uneven mechanical behaviour; brittle seismogenic faulting is confined to the strong brittle part of the middle crust. This strong brittle layer might also act as a stress guide able to laterally transmit the deviatoric stresses responsible for the strike–slip regime in the Apulian crust and may explain the close proximity (nearly overlapping) of the strike–slip and normal faulting regimes in the Southern Apennines. From a methodological point of view, it seems that rather simple two-mechanism rheological profiles, though affected by uncertainties, are still a useful tool for estimating the rheological properties and likely seismogenic behaviour of the crust.
    Description: Published
    Description: 281–300
    Description: 3.2. Tettonica attiva
    Description: JCR Journal
    Description: reserved
    Keywords: Strike–slip seismicity; ; Deep crust; ; Active stress; ; Crustal rheology; ; Seismotectonics; ; Southern Apennines ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    facet.materialart.
    Unknown
    Istituto Nazionale di Geofisica e Vulcanologia, Editrice Compositori
    Publication Date: 2019-11-04
    Description: A one-day symposium on new and conventional ideas in plate tectonics and Mediterranean geodynamics was held in Rome on February 19, 2003 at the headquarters of INGV. There were two main reasons for such an initiative. The first was an invitation to Giancarlo Scalera from the «Gabriele D’Annunzio» University of Chieti to present his alternative ideas on global tectonics to final year students of the Regional Geology course. The second was a reciprocal invitation to Giusy Lavecchia and Francesco Stoppa to explain their criticisms of the application of subduction-related models to Italian geology and to present their data on the recently discovered intra-Apennines carbonatite occurrences. It was decided to dedicate an entire day to seminars, involving people with a more conventional approach to geodynamics, especially those involved with seismic tomography. In the last few years, high-resolution mantle tomographic models have been widely used to unravel the geometry of subduction zones. A turning point in the field, however, was a review paper written by Fukao et al. (Rev. Geophysics, 39, 291-323, 2001) showing that there was no clear evidence for slab subduction down to the core-mantle boundary, thus posing a major problem on the balance between the lithosphere subducted at consuming plate margins and the large amount of oceanic lithosphere accreted at diverging plate margins. This prompted the need to re-evaluate the nature of subduction and plate margin evolution. Accepting the theory of plate tectonics, many problems remain open, especially those regarding plate driving mechanisms and their possible link with the forces developed at the core-mantle boundary. Might these forces trigger pulsating tectonic and magmatic activity, with mantle upwellings and large-scale emission of CO2, capable of causing dramatic changes in the composition of the atmosphere and changes at the Earth’s surface? Could these lead to major catastrophic changes in Earth history? During the one-day symposium, a stimulating discussion took place involving different interpretations of observations, especially those relating to the geodynamics of the Mediterranean region. Although the papers in this collection do not provide unique solutions, they do, however, provide new insights into some problems and in some cases suggest new interpretations. Many questions also arise about the relationships between the tectonics of the lithosphere and the deep mantle processes. May the denser portions of the inner parts of the Earth transform into shallower, lighter chemical phases, with a possible increase in the Earth’s volume? May the asthenosphere above growing plume heads be capable of dragging the overlying lithosphere? May mantle plumes be wet rather than hot? Some papers consider gravitation to be a driving mechanism for the nucleation of contractional belts and others even doubt the compressional origin of orogens. Finally – as a link to fundamental physics – an original mechanism of energy conversion from gravitons to photons is proposed as a supply of energy for global tectonic processes. Obviously, because of an often diverse philosophical and scientific background, it is difficult for the ideas presented in this supplement to be shared by all readers and contributors. But we hope that these ideas will help to encourage critical evaluations of some commonly accepted concepts in modern plate tectonic theory. European geoscientists have available to them an exceptional natural laboratory – the Mediterranean and surrounding orogens – complete with all of its paradoxes and contradictions. In this natural laboratory, we hope that new evidence and new solutions to a variety of problems outside of the Mediterranean region will be found!
    Description: Published
    Description: JCR Journal
    Description: open
    Keywords: alternative theories in the Earth sciences ; conventional theories in the Earth sciences ; 04. Solid Earth::04.01. Earth Interior::04.01.02. Geological and geophysical evidences of deep processes ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.04. Plate boundaries, motion, and tectonics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Format: 78012 bytes
    Format: 7264144 bytes
    Format: 5097129 bytes
    Format: 1911585 bytes
    Format: 1660281 bytes
    Format: 2195335 bytes
    Format: 4373266 bytes
    Format: 1470973 bytes
    Format: 720760 bytes
    Format: 5563234 bytes
    Format: 3327762 bytes
    Format: 3125259 bytes
    Format: 164985 bytes
    Format: 61896 bytes
    Format: 60272 bytes
    Format: application/pdf
    Format: application/pdf
    Format: application/pdf
    Format: application/pdf
    Format: application/pdf
    Format: application/pdf
    Format: application/pdf
    Format: application/pdf
    Format: application/pdf
    Format: application/pdf
    Format: application/pdf
    Format: application/pdf
    Format: application/pdf
    Format: application/pdf
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Publication Date: 2024-05-09
    Description: In this paper, we propose a new model of the crustal structure and seismotectonics for central Sicily (southern Italy) through the analysis of the depth distribution and kinematics of the instrumental seismicity, occurring during the period from 1983 to 2010, and its comparison with individual geological structures that may be active in the area. The analysed data set consists of 392 earthquakes with local magnitudes ranging from 1.0 to 4.7. We defined a new, detailed 1-D velocity model to relocate the earthquakes that occurred in central Sicily, and we calculated a Moho depth of 37 km and a mean VP/VS ratio of 1.73. The relocated seismic events are clustered mainly in the area north of Caltanissetta (e.g. Mainland Sicily) and in the northeastern sector (Madonie Mountains) of the study area; only minor and greatly dispersed seismicity is located in the western sector, near Belice, and along the southern coast, between Gela and Sciacca. The relocated hypocentral distribution depicts a bimodal pattern: 50 per cent of the events occur within the upper crust at depths less than ~16 km, 40 per cent of the events occur within the middle and depth crust, at depths between 16 and 32 km, and the remaining 10 per cent occur at subcrustal depths. The energy release pattern shows a similar depth distribution. On the basis of the kinematic analysis of 38 newly computed focal plane solutions, two major geographically distinct seismotectonic domains are distinguished: the Madonie Mountain domain, with prevalent extensional and extensional-oblique kinematics associated with upper crust Late Pliocene–Quaternary faulting, and the Mainland Sicily domain, with prevalent compressional and compressional-oblique kinematics associated with thrust faulting, at mid to deep crust depth, along the north-dipping Sicilian Basal Thrust (SBT). The stress inversion of the Mainland Sicily focal solutions integrated with neighbouring mechanisms available in the literature highlights a regional homogeneous compressional tensor, with a subhorizontal NNW–SSE-striking σ1 axis. In addition, on the basis of geodetic data, the Mainland Sicily domain may be attributed to the SSE-ward thrusting of the Mainland Sicily block along the SBT plane. Seismogenic shearing along the SBT at mid-crustal depths was responsible for the unexpected Belice 1968 earthquake (Mw 6.1), with evident implications in terms of hazard assessment.
    Description: Published
    Description: 1237-2252
    Description: 1.1. TTC - Monitoraggio sismico del territorio nazionale
    Description: 3.2. Tettonica attiva
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: 5.2. TTC - Banche dati di sismologia strumentale
    Description: JCR Journal
    Description: restricted
    Keywords: Seismicity and tectonics ; Continental tectonics: compressional ; Dynamics: seismotectonics ; Crustal structure ; Europe ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous ; 04. Solid Earth::04.06. Seismology::04.06.01. Earthquake faults: properties and evolution ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.99. General or miscellaneous ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.04. Plate boundaries, motion, and tectonics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...