The new release of the database of Earthquake Mechanisms of the Mediterranean Area (EMMA Version 2)

We present here the second release of a database, running on MS-Access platform, of the earthquake focal mechanisms of the Mediterranean area, published in the literature. For all of the mechanisms (more than 6000) the published parameters, taken from about 193 papers, have been checked for consistency and if necessary corrected when possible. The MS-Access application also allows the major moment tensor catalogs available for the area to be imported (without checking) and used

Kinematic block modeling of GPS velocities in Italy and seismic potential

We use a dense GPS velocity field, from the analysis of >1000 continuous stations, and elastic block modeling to study the interseismic strain accumulation along the Alpine and Apennines active tectonic belts in Italy. We consider available fault catalogues, instrumental and historical seismicity to determine the blocks boundaries geometry, parameterized as uniformly slipping rectangular planes. We invert horizontal velocities to estimate Euler vectors of tectonic blocks together with slip-rates at block-bounding faults. When allowed by density of GPS data, we optimize faults dip and locking-depth by searching the parameters that provide the best fit to local GPS data. Overall we obtain a good fit of the horizontal velocities and geodetic slip rates that are kinematically consistent with available geological and seismotectonic information. We use the best-fit geometric and kinematic model parameters to compute the expected GPS velocities over a dense regular grid. Denser model velocities are used to estimate the velocity gradient field on a regular grid, made by cell elements of 0.25°x0.25°. Geodetic strain-rates at each cell are converted into seismic moment accumulation rates, following the Kostrov formulation, considering as seismogenic thickness values obtained from a crustal (EPcrust) model and earthquake hypocentral distribution. Geodetic moment accumulation rates are compared with seismic moment rates released by earthquakes, obtained from the analysis of a seismic catalogue realized by merging several instrumental and historical catalogues covering the 1600-2012 timespan, and uniformly defined moment magnitudes. The comparison between geodetic moment accumulation rates and seismic moment release rates highlights regions with significant moment deficits but also areas with a surplus of the seismic moment released, with important implications for seismic hazard evaluations and assumptions behind the approach used in this work

Geometry and modeling of an active offshore thrust-related fold system: the Amendolara Ridge, Ionian Sea, southern Italy

On the Ionian Sea coast of southern Italy, spanning the transition from the Calabrian Arc to the Apennines, NE-directed motion of the thin-skinned frontal thrust belt of the Apennines toward the Apulian foreland reportedly ceased during the Early-Middle Pleistocene. The submarine extension of the frontal thrust belt is represented by the Amendolara ridge, which stretches for over 80 km to the SE beneath the Taranto Gulf. High-resolution marine geophysical data collected on the Amendolara ridge during the TEATIOCA_2011 cruise provided unequivocal constraints to assert active fault-related fold growth. Single-channel seismic (sparker) and acoustic CHIRP profiles, corroborated by multibeam mapping and shallow coring, form the novel dataset to constrain the near-bottom evolution. The new data were benchmarked to the crustal geometry by means of interpretation of existing multichannel seismic profiles

An atlas of Mediterranean seismicity

We present a description of the characteristics of the seismic deformation occurring in the Alpine Mediterranean Belt, and outline its association with tectonic and geologic features. We map seismic activity using several catalogues. Hypocentral data are retrieved from the Catalog of the International Seismological Center, the most comprehensive compilation of global data. Earthquake size and source geometry are instead evaluated from catalogs of earthquake mechanisms. These include seismic moment tensor catalogs (mainly the Harvard CMT Catalog, the Euro-Mediterranean Regional Centroid-Moment Tensors – RCMT Catalog and the regional moment tensor determination in the European-Mediterranean area – ETH Catalog) and a recent extensive compilation of solutions available in literature (EMMA) that provides consistency-controlled fault-plane solutions where mechanisms based on waveform fitting are missing. The study area follows the Africa-Eurasia margin from the Central Atlantic to Iran, and it has been divided into several provinces for the sake of presentation and graphic purposes. For each province, a brief geologic and tectonic description complements the outline of the pattern of seismicity, illustrated by several maps. Focal mechanisms are also grouped together to yield average mechanisms and enable synoptic views. A comprehensive bibliography is referenced. A CD-ROM accompanying this issue contains, besides maps, figures and results of local comparisons and summation of moment tensors with easy access via sensible maps, also an updated version of the EMMA focal mechanism database. Rather than an attempt at presenting a comprehensive seismotectonic model of the Mediterranean, this contribution aims to offer a panoramic view of the active tectonics as imaged by seismicity and focal mechanisms. Its scope may be seen as similar to that of an atlas, as a broad reference and a support for more specific studies

Individuazione di strutture attive nell'Appennino centrosettentrionale sulla base di dati macrosismici storici

Dottorato di ricerca in tettonica e geologia strutturale. 12. ciclo. A.a. 1996-99. Tutore Giovanni Deiana. Co-tutore Paolo GasperiniConsiglio Nazionale delle Ricerche - Biblioteca Centrale - P.le Aldo Moro, 7, Rome; Biblioteca Nazionale Centrale - P.za Cavalleggeri, 1, Florence / CNR - Consiglio Nazionale delle RichercheSIGLEITItal

FPSPACK: a package of FORTRANsubroutines to manage earthquake focal mechanism data

Abstract Earthquakes fault plane solutions (FPSs) are routinely computed on the basis of various techniques and are reported in the literature with a wide range of formats and conventions. Although the equations relating the various parameters are well known and relatively simple, their practical application often arise to numerical singularities and indeterminations that sometimes are not well known by the authors and thus may result in wrong or inaccurate reporting of parameters. Such inaccuracies and mistakes affect about 40% of the published data we have examined to test our programs. Moreover the current use, in the seismological community, of at least two different coordinate systems to represent the Cartesian components of vectorial and tensorial quantities is a further cause of confusion. In order to simplify the management of such data, we have prepared a structured package of FORTRAN 77 subroutines performing almost all of the possible computations and conversions among different parameters and coordinate systems. The package has been extensively tested with the data of a revised database of FPS of Italy and surrounding regions (presented in a companion paper) as well as of CMT solutions included in the Harvard catalog.