9 research outputs found
Earthquake Mechanisms of the Mediterranean Area (EMMA) version 3: an improved tool for characterizing the tectonic deformation styles in the Mediterranean
Geophysical Research Abstracts,
Vol. 11, EGU2009-7974, 2009
EGU General Assembly 2009
© Author(s) 2009
Earthquake Mechanisms of the Mediterranean Area (EMMA) version 3:
an improved tool for characterizing the tectonic deformation styles in the
Mediterranean.
G. Vannucci (1), P. Imprescia (2), and P. Gasperini (3)
(1) INGV-Istituto Nazionale di Geofisica e Vulcanologia, Via Donato Creti, 12, I-40128, Bologna (Italy), [email protected],
(2) Dipartimento Scienze Geologiche, UniversitĂ di Catania, Corso Italia, 57, I-95129 Catania (Italy), [email protected],
(3) Dipartimento di Fisica, UniversitĂ di Bologna, Viale Berti-Pichat 8, I-40127 Bologna (Italy), [email protected]
EMMA (Earthquake Mechanisms of the Mediterranean Area) database contains available literature data with the
goal of making them more usable and available. EMMA is continuously improving by the addition of further
focal mechanisms found in literature. At the present time, EMMA pre-release 3 includes more than 12700 focal
solutions, about twice of previous official release 2.2 (Vannucci and Gasperini, 2004). They cover a time window
from 1905 to 2006. In the new release, many added solutions are in areas not much covered or completely
uncovered in the previous one (e.g. Bulgaria, Germany, Anatolia).
As in the previous versions (Vannucci and Gasperini, 2003 and 2004), we have uniformed the different formats
and notations of the data available from different sources and we have tried to solve misprints, inaccuracies and
inconsistencies that might make the data unusable for other investigations. By an automatic procedure based on
several criteria, we have chosen the âmost representativeâ (best) solution when more than one is available for
the same earthquake. Thanks to this, we have obtained about 6000 best solutions. The end user can use the best
solution obtained with our procedure or he can change criteria.
The database allows to make selections and to export data files suitable to be handled by graphic software and
user generated scripts. In the new version, still MS-ACCESS based, we have added geographic information to
the display of the focal solution, as well as we have integrated the hypocentral and magnitude data found on the
original papers with those reported by regional and local catalogs and bulletins.
In order to make EMMA more accessible, a web version is currently in progress. Through an internet connection
it will be possible data selection and export, without installation and configuration problems found in the past.
EMMA was already used in the past and will be (hopefully) useful in the future to better characterize the tectonic
deformation styles (e.g. by moment tensors sum within given areas or over regular geographical grids) particularly
in areas of the European region where seismicity is moderate and only few CMT solutions are available.
At the moment, we try to compute strain map for Mediterranean area, using EMMA data. In order to represent
any recurrence in space, we identify small areas and apply to each one some spatial analyses. The work is still in
progress, but preliminary results are satisfactory and in accord to previous studies
Current stress and strain-rate fields across the Dead Sea Fault System: Constraints from seismological data and GPS observations
The stress and strain-rate fields characterizing the Dead Sea Fault System are investigated by using seismological and geodetic observations. In order to assess spatial variations in the regional stress field, we compiled a multidisciplinary dataset of well-constrained horizontal indicators, by merging all available data reported in literature with the data obtained in this study through weighted stress inversions of focal plane solutions. Our findings indicate that the state of stress is characterized by the coexistence of a normal faulting stress regime with the primarily strike-slip one, according to the regional frame illustrated by previous geological and seismological observations. An updated velocity field computed from new observations and earlier published data depicts the general left-lateral motion of the Dead Sea Fault System well. In agreement with previous studies, we detected some differences in the slip-rate pattern between the northern and the southern sectors of the fault system. The geodetic strain-rate field highlights how much of the deformation is accommodated along the fault system itself in a narrow region. The comparison between the stress and the strain-rate directions reveals that both orientations are near-parallel, clearly indicating that present-day crustal stress and ground deformation patterns are chiefly driven by the same tectonic processes. (C) 2013 Elsevier B.V. All rights reserved
Earthquake Mechanisms of the Mediterranean Area (EMMA) version 3: an improved tool for characterizing the tectonic deformation styles in the Mediterranean
Geophysical Research Abstracts,
Vol. 11, EGU2009-7974, 2009
EGU General Assembly 2009
© Author(s) 2009
Earthquake Mechanisms of the Mediterranean Area (EMMA) version 3:
an improved tool for characterizing the tectonic deformation styles in the
Mediterranean.
G. Vannucci (1), P. Imprescia (2), and P. Gasperini (3)
(1) INGV-Istituto Nazionale di Geofisica e Vulcanologia, Via Donato Creti, 12, I-40128, Bologna (Italy), [email protected],
(2) Dipartimento Scienze Geologiche, UniversitĂ di Catania, Corso Italia, 57, I-95129 Catania (Italy), [email protected],
(3) Dipartimento di Fisica, UniversitĂ di Bologna, Viale Berti-Pichat 8, I-40127 Bologna (Italy), [email protected]
EMMA (Earthquake Mechanisms of the Mediterranean Area) database contains available literature data with the
goal of making them more usable and available. EMMA is continuously improving by the addition of further
focal mechanisms found in literature. At the present time, EMMA pre-release 3 includes more than 12700 focal
solutions, about twice of previous official release 2.2 (Vannucci and Gasperini, 2004). They cover a time window
from 1905 to 2006. In the new release, many added solutions are in areas not much covered or completely
uncovered in the previous one (e.g. Bulgaria, Germany, Anatolia).
As in the previous versions (Vannucci and Gasperini, 2003 and 2004), we have uniformed the different formats
and notations of the data available from different sources and we have tried to solve misprints, inaccuracies and
inconsistencies that might make the data unusable for other investigations. By an automatic procedure based on
several criteria, we have chosen the âmost representativeâ (best) solution when more than one is available for
the same earthquake. Thanks to this, we have obtained about 6000 best solutions. The end user can use the best
solution obtained with our procedure or he can change criteria.
The database allows to make selections and to export data files suitable to be handled by graphic software and
user generated scripts. In the new version, still MS-ACCESS based, we have added geographic information to
the display of the focal solution, as well as we have integrated the hypocentral and magnitude data found on the
original papers with those reported by regional and local catalogs and bulletins.
In order to make EMMA more accessible, a web version is currently in progress. Through an internet connection
it will be possible data selection and export, without installation and configuration problems found in the past.
EMMA was already used in the past and will be (hopefully) useful in the future to better characterize the tectonic
deformation styles (e.g. by moment tensors sum within given areas or over regular geographical grids) particularly
in areas of the European region where seismicity is moderate and only few CMT solutions are available.
At the moment, we try to compute strain map for Mediterranean area, using EMMA data. In order to represent
any recurrence in space, we identify small areas and apply to each one some spatial analyses. The work is still in
progress, but preliminary results are satisfactory and in accord to previous studies.PublishedWien5.2. TTC - Banche dati di sismologia strumentaleope
Current stress and strain-rate fields across the Dead Sea Fault system: constraints from seismological data and GPS observations.
The stress and strain-rate fields characterizing the Dead Sea Fault System are investigated by using seismological and geodetic observations. In order to assess spatial variations in the regional stress field, we compiled a multidisciplinary dataset of well-constrained horizontal indicators, by merging all available data reported in literature with the data obtained in this study through weighted stress inversions of focal plane solutions. Our findings indicate that the state of stress is characterized by the coexistence of a normal faulting stress regime with the primarily strike-slip one, according to the regional frame illustrated by previous geological and seismological observations. An updated velocity field computed from new observations and earlier published data, depicts the general left-lateral motion of the Dead Sea fault system well. In agreement with previous studies, we detected some differences in the slip-rate pattern between the northern and the southern sectors of the fault system. The geodetic strain-rate field highlights how much of the deformation is accommodated along the fault system itself in a narrow region. The comparison between the stress and the strain-rate directions reveals that both orientations are near-parallel, clearly indicating that present-day crustal stress and ground deformation patterns are chiefly driven by the same tectonic processes
Current stress and strain-rate fields across the Dead Sea Fault system: constraints from seismological data and GPS observations.
The stress and strain-rate fields characterizing the Dead Sea Fault System are investigated by using seismological and geodetic observations. In order to assess spatial variations in the regional stress field, we compiled a multidisciplinary dataset of well-constrained horizontal indicators, by merging all available data reported in literature with the data obtained in this study through weighted stress inversions of focal plane solutions. Our findings indicate that the state of stress is characterized by the coexistence of a normal faulting stress regime with the primarily strike-slip one, according to the regional frame illustrated by previous geological and seismological observations. An updated velocity field computed from new observations and earlier published data, depicts the general left-lateral motion of the Dead Sea fault system well. In agreement with previous studies, we detected some differences in the slip-rate pattern between the northern and the southern sectors of the fault system. The geodetic strain-rate field highlights how much of the deformation is accommodated along the fault system itself in a narrow region. The comparison between the stress and the strain-rate directions reveals that both orientations are near-parallel, clearly indicating that present-day crustal stress and ground deformation patterns are chiefly driven by the same tectonic processes.Published305-3162T. Tettonica attivaJCR Journalrestricte
An improved evaluation of the seismic/geodetic deformation-rate ratio for the Zagros Fold-and-Thrust collisional belt
We present an improved picture of the ongoing crustal deformation field for the Zagros Fold-and-Thrust Belt continental collision zone by using an extensive combination of both novel and published GPS observations. The main results define the significant amount of oblique Arabia-Eurasia convergence currently being absorbed within the Zagros: right-lateral shear along theNWtrending Main Recent fault inNWZagros and accommodated between fold-andthrust structures and NS right-lateral strike-slip faults on Southern Zagros. In addition, taking into account the 1909-2016 instrumental seismic catalogue, we provide a statistical evaluation of the seismic/geodetic deformation-rate ratio for the area. On Northern Zagros and on the Turkish-Iranian Plateau, a moderate to large fraction (~49 and >60 per cent, respectively) of the crustal deformation occurs seismically. On the Sanandaj-Sirjan zone, the seismic/geodetic deformation-rate ratio suggests that a small to moderate fraction (<40 per cent) of crustal deformation occurs seismically; locally, the occurrence of large historic earthquakes (M â„ 6) coupled with the high geodetic deformation, could indicate overdue M â„ 6 earthquakes. On Southern Zagros, aseismic strain dominates crustal deformation (the ratio ranges in the 15-33 per cent interval). Such aseismic deformation is probably related to the presence of the weak evaporitic Hormuz Formation which allows the occurrence of large aseismic motion on both subhorizontal faults and surfaces of deÌcollement. These results, framed into the seismotectonic framework of the investigated region, confirm that the fold-and-thrust-dominated deformation is driven by buoyancy forces; by contrast, the shear-dominated deformation is primary driven by plate stresse
Regional centroid moment tensor solutions in Cyprus from 1977 to the present and seismotectonic implications
We analyzed digital seismic records in
order to extend back in time the catalog of regional
centroid moment tensors (RCMTs) for the Cyprus
region. We applied the analysis and inversion methodology
also used for the present-day seismicity on
seismograms recorded at regional distance. We
computed 18 new regional CMTs of earthquakes of
moderate magnitude (4.8â€Mâ€5.5) which occurred in
the Cyprus region for the time span 1977â1996.
These new focal mechanisms improved the knowledge
given by the previously computed solutions carried out
by other institutions, as well as the dataset of available
earthquake source parameters. The complete focal
mechanism database contributed to better define the
deformation styles in the study area and to obtain a
detailed characterization of the geodynamics of the
Cyprus area. New RCMTs support the hypothesis that
Cyprus is located in the middle of the transition area from subduction to continental collision along the
AfricaâArabianâEurasian boundary. In particular, data
confirm (a) this transition zone is strictly located west of
Cyprus, probably related to a tear in the subduction
system, and (b) the still active compression in the
Cyprus Arc can be seen as a starting point of the
continental collision eastward
Regional Moment Tensor Review: An Example from the 2 EuropeanâMediterranean Region
The seismic moment tensor is the complete mathematical representation of the movement on a fault
10 during an earthquake, comprising of the couples of forces that produced it, the description of the fault
11 geometry, and its size by means of the scalar seismic moment M0.
12 The computation of seismic moment tensor has become a widely diffused activity because of the
13 relevance of this kind of data in seismotectonic and geodynamic studies and, in more recent times,
14 because it allows obtaining rapid information about a seismic event immediately after its occurrence. This
15 progress has been possible with the advent of modern standardized instruments since the early 1960s,
16 above all of the very broadband seismographic stations that started to record in the late 1970s. Further-
17 more, time after time, the easier availability of digital data impressed a strong incentive to improve the
18 procedures of source parameter computation.Unpublished1-154IT. Banche datirestricte