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| Titel |
New insights on the seismic hazard in the Balkans inferred from GPS |
| VerfasserIn |
Nicola D'Agostino, Marianne Metois, Antonio Avallone, Nicolas Chamot-Rooke |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250091691
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| Publikation (Nr.) |
 EGU/EGU2014-5996.pdf |
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| Zusammenfassung |
| The Balkans region sits at the transition between stable Eurasia and highly straining
continental Eastern Mediterranean, resulting in a widespread seismicity and high seismic
hazard. Because of intensive human and economic development over the last decades, the
vulnerability has increased in the region faster than the progress in seismic hazard
assessments. Opposite to the relatively good understanding of the seismicity in
plate boundaries contexts, the seismic hazard is poorly known in the regions of
distributed continental deformation like the Balkan region and is often underestimated
(England and Jackson, 2011). Current seismic hazard assessments are based on the
historical and instrumental catalogues. However, the completeness interval of the
historical data bases may be below the average recurrence of individual seismogenic
structures. In addition, relatively sparse seismological networks in the region and limited
cross-border seismic data exchanges cast doubts in seismotectonic interpretation and
challenge our understanding of seismic and geodynamic processes. This results in a
inhomogeneous knowledge of the seismic hazard of the region to date. Geodetic
measurements have the capability to contribute to seismic hazard by mapping the field
of current active deformation and translating it into estimates of the seismogenic
potential. With simple assumptions, measurements of crustal deformation can be
translated in estimates of the average frequency and magnitude of the largest events and
assessments of the aseismic deformation. GPS networks in the Balkans have been
growing during the last few years mainly for civilian application (e.g. Cadastral plan,
telecommunications), but opening new opportunities to quantify the present-day rates of
crustal deformation.
Here we present the initial results of GEOSAB (Geodetic Estimate of Strain
Accumulation over Balkans), an AXA-Research-Fund supported project devoted to the
estimation of crustal deformation and the associated seismic hazard of the Balkan region. We
processed all the currently available data acquired on these new networks using the precise
point positioning strategy of the Gipsy-Oasis software (Bertiger et al. 2010) and the
daily ITF2008 transformation parameters (x-files) from JPL. Daily coordinates are
obtained in a Eurasia-fix reference frame obtained using the strategy developed
by Blewitt et al. (2012). Here we present this new velocity field combined with
previously published data sets covering the Balkan Peninsula. This unusually dense
picture of the current deformation, in particular in Slovenia and Serbia, enables us to
derive a continuous map of the strain rate over the region using the approach of
Haines and Holt (1993). We then derive the seismogenic potential of the region
combining the geodetic strain rate and the available regional CMT moment tensor
solutions. These maps bring new insights on areas of significant strain accumulation
over the Balkan Peninsula and are a first step to better assess seismic hazard there. |
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