HR: 1340h
AN: G13A-0925    [Abstracts]
TI: Post-Seismic Slip of the February 2004 Earthquake Swarm Detected by GPS in West Bohemia, Central Europe
AU: * Schenk, V
EM: schenk@irsm.cas.cz
AF: Institute of Rock Structure and Mechanics, v.v.i., Academy of Sciences of the Czech Republic, V Holesovickach 41, Prague, 18209, Czech Republic
AU: Jechumtalova, Z
EM: zs@ig.cas.cz
AF: Institute of Geophysics, v.v.i., Academy of Sciences of the Czech Republic, Bocni II/1401, Prague, 14131, Czech Republic
AU: Schenkova, Z
EM: zdschenk@irsm.cas.cz
AF: Institute of Rock Structure and Mechanics, v.v.i., Academy of Sciences of the Czech Republic, V Holesovickach 41, Prague, 18209, Czech Republic
AB: In last decades earthquake swarms in West Bohemia, Central Europe, are monitored by a local seismic network WEBNET consisting of nine stations. In 2003 two GPS permanent observatories MARJ and POUS belonging to European permanent network EPN were established in NW Bohemia to detect possible inter-, co- and post- seismic slips of the earthquake swarms. Individual swarm events are often clustered and grouped sharply round a few tectonic fault zones. On 22 February 2004 a deep swarm of around 50 events in magnitude ML range -0.5 to 1.4 occurred in the Novy Kostel zone. Most of its events fitted in elongated cluster with -30° strike in the depth of 13.5 km differed from the main -11° strike of the Novy Kostel zone. The cluster lay 2 km apart from the main fault plane to west and preliminary focal event mechanisms displayed dip-slip regime. This two azimuth foci bifurcation most likely corresponds to two tectonic systems of this area. After the February 2004 swarm for almost two weeks the total post-seismic slip up to 10 mm was observed between time series of GPS observatories. The detected slip seems to match well to the deep-seated fault system with the -30° strike. It is remarkable that this system fits well just to pronounce gravity gradient zone existing in this area. Mutual relations among the slip movements, local earthquake occurrences and geological data will be displayed and discussed. The research was supported by the Czech Science Foundation (Project 205/05/2287), the Grant Agency of the Academy of Sciences CR (Project IAA300460507), the Support of Targeted Research programme (Project QS300460551) and the Ministry of Education, Youth and Sport (Projects LC506 and 1P05ME781).
DE: 1209 Tectonic deformation (6924)
DE: 1242 Seismic cycle related deformations (6924, 7209, 7223, 7230)
DE: 7230 Seismicity and tectonics (1207, 1217, 1240, 1242)
DE: 8004 Dynamics and mechanics of faulting (8118)
DE: 8123 Dynamics: seismotectonics
SC: Geodesy [G]
MN: 2007 Fall Meeting