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| Titel |
Velocity structure and the role of fluids in the West Bohemia Seismic Zone |
| VerfasserIn |
C. Alexandrakis, M. Calo, F. Bouchaala, V. Vavryčuk |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1869-9510
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| Digitales Dokument |
URL |
| Erschienen |
In: Solid Earth ; 5, no. 2 ; Nr. 5, no. 2 (2014-08-27), S.863-872 |
| Datensatznummer |
250115331
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| Publikation (Nr.) |
 copernicus.org/se-5-863-2014.pdf |
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| Zusammenfassung |
| In this study, we apply the double-difference tomography to investigate the
detailed 3-D structure within and around the Nový Kostel Seismic Zone, an
area in the Czech Republic known for frequent occurrences of earthquake
swarms. We use data from the 2008 swarm since it has already been analysed in
terms of earthquake focal mechanisms, principal faults, tectonic stress and
foci migration. We selected about 500 microearthquakes recorded at 22 local
seismic stations of the West Bohemia
seismic monitoring network
(WEBNET). Applying
double-difference tomography, combined with weighted average model (WAM)
post-processing to correct for parameter dependence effects, we produce and
interpret 3-D models of the Vp-to-Vs ratio (Vp/Vs) in and around the
focal zone. The modelled Vp/Vs ratio shows several distinct
structures, namely an area of high Vp/Vs ratio correlating with the
foci of the microearthquakes, and a layer of low values directly above it.
These structures may reflect changes in lithology and/or fluid concentration.
The overlaying low Vp/Vs ratio layer coincides with the base of the
Fichtelgebirge (Smrčiny) granitic intrusion. It is possible that the base
of the layer acts as a fluid trap and an upper limit to the seismicity,
resulting in observed periodic swarms. |
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