Helmholtz Centre Potsdam
GFZ German Research Centre for Geosciences
Abstract (EDOC: 6865)
The 1985/86 series is revisited by modelling some pronounced features of the observed P waveforms frequently seen in the records of the CLL, BRG and the GRF seismograph stations. Travel times and waveforms can be explained by a simple two-layer crustal model consisting of an upper crust with V"SUB P" = 5.9 km/s and thickness t = 18 km, and a lower crust with V"SUB P" = 6.8 km/s and t = 11 km. The crust-mantle boundary is at 29 km depth. Waveforms recorded at distances between about 100 and 120 km consist of a low-amplitude first P wave which has travelled through the lower crust. This phase is followed about 0.5 to 1 s later by the large-amplitude main event. The focal depth of the main shock is constrained to 9 km. Depths of the stronger events (M"SUB L" > 3) of the swarm are within the depth range from 7 to 10 km. Inversion of body wave amplitudes and P wave polarities for the focal mechanism of the main events reveals a strike-slip mechanism which agrees well with previously published results.
(1996): The 1985/1986 western Bohemia earthquakes: modelling source parameters with synthetic seismograms. Tectonophysics, 261, 1-3, 139-146.