HR: 1340h
AN: S33B-0317    [Abstracts]
TI: Horizontal Love-wave phase velocity estimates: seismic array measurements vs. point measurements
AU: suryanto, w
EM: wiwit@geophysik.uni-muenchen.de
AF: Department of Earth and Environmental Sciences, Theresienstr. 41, Munich, 80333 Germany
AU: * Igel, H
EM: heiner.igel@lmu.de
AF: Department of Earth and Environmental Sciences, Theresienstr. 41, Munich, 80333 Germany
AU: Wassermann, J
EM: jowa@geophysik.uni-muenchen.de
AF: Department of Earth and Environmental Sciences, Theresienstr. 41, Munich, 80333 Germany
AU: Schuberth, B
EM: schuberth@geophysik.uni-muenchen.de
AF: Department of Earth and Environmental Sciences, Theresienstr. 41, Munich, 80333 Germany
AU: Cochard, A
EM: alain@geophysik.uni-muenchen.de
AF: Department of Earth and Environmental Sciences, Theresienstr. 41, Munich, 80333 Germany
AU: Schreiber, U
EM: schreiber@wettzell.ifag.de
AF: Satellitengeod„sie, Funamentalstation Wettzell, Koetzting, 93444 Germany
AU: Velikoseltsev, A
EM: alex@wettzell.ifag.de
AF: Satellitengeod„sie, Funamentalstation Wettzell, Koetzting, 93444 Germany
AU: Scherbaum, F
EM: fs@geo.uni-potsdam.de
AF: Institut fr Geowissenschaften, Postfach 60 15 53, Potsdam, 14415 Germany
AU: Vollmer, D
EM: daniel@geo.uni-potsdam.de
AF: Institut fr Geowissenschaften, Postfach 60 15 53, Potsdam, 14415 Germany
AB: Recently, ring-laser based measurements of rotational ground motions around a vertical axis were shown to be consistent in phase and amplitude with collocated recordings of translations with standard broadband seismometers. The consistency is based on the theoretical relation between transverse acceleration and rotation rate. Assuming plane wave propagation and transverse polarization they should be in phase and their amplitude ratio proportional to horizontal phase velocity. In turn, this implies that estimates of horizontal phase velocities, particularly of Love waves, should be possible with this point measurement of rotation and translations. Otherwise, this would only be possible with a seismic array or additional strain measurements. To compare these estimates with classical array-type processing, a seismic array with 3 km diameter and nine seismic stations was installed in 2004 for several months around the location of the ring laser system. This allowed us to compare array-derived phase velocity estimates with those of the point measurements and analytical Love-wave dispersion curves calculated for 1D local Earth models. The observational study is supported by the application of the same processing steps to complete 3D synthetic seismograms for some of the observed events for the seismic array and the rotational motions. Initial results suggest that the point measurements capture well the horizontal phase velocities and Love-wave dispersion behavior. Such point-measurements with additional rotational sensors may proove to be useful for very sparse or single-station networks (e.g., in planetary seismology).
UR: http://ringlaser.geophysik.uni-muenchen.de
DE: 7255 Surface waves and free oscillations
DE: 7260 Theory
DE: 7294 Seismic instruments and networks (0935, 3025)
SC: Seismology [S]
MN: Fall Meeting 2005