HR: 09:45h
AN: S41C-08 [Abstracts]
TI: Upper mantle of the Bohemian Massif (Central Europe) studied by surface waves from Kurile Islands M8.1 and M8.3 earthquakes
AU: * Kolinsky, P
EM: kolinsky@irsm.cas.cz
AF: Institute of Rock Structure and Mechanics, Academy of Sciences of the Czech Republic, V
Holesovickach 41, Prague, 182 09, Czech Republic
AU: Malek, J
EM: malek@irsm.cas.cz
AF: Institute of Rock Structure and Mechanics, Academy of Sciences of the Czech Republic, V
Holesovickach 41, Prague, 182 09, Czech Republic
AB:
Two strong earthquakes of M8.3 and M8.1 occurred near Kurile Islands in December 2006 and January 2007.
Broadband surface wave records were obtained at many stations in Central Europe in the epicentral distance of
about 8500 km. We have analyzed broadband seismograms from the Czech Regional Seismic Network together
with twelve temporary stations of the Institute of Rock Structure and Mechanics. We present a surface wave phase
velocity analysis of several interstation paths of length around 150 km crossing the Bohemian Massif. This
geological unit located in Central Europe is of Variscan age and its upper mantle seismic structure is still under
investigation. Both Love and Rayleigh waves in the period range from 20 to 180 s have been studied. We provide
polarization analysis to show the true backazimuths of surface wave propagation paths. We use also an array
approach of our 7-stations broadband array placed near the center of the Bohemian Massif. We present Love-
Rayleigh wave discrepancy as well as vertical-radial Rayleigh wave discrepancy pronounced in different period
bands. The most striking feature is the low Love wave phase velocity around the period of 130 s. 1-D inversion of
the phase velocity dispersion curves has been computed. Phase velocity dispersion curve anomalies are
interpreted as a consequence of low velocity channel in the middle crust and upper mantle anisotropy.
UR: http://www.irsm.cas.cz
DE: 7255 Surface waves and free oscillations
SC: Seismology [S]
MN: 2007 Fall Meeting