HR: 15:10h
AN: S32D-07    [PDF]
TI: A Possible Triggering Mechanism for the Earthquake Swarms in Vogtland/NW-Bohemia: Data Analysis and Numerical Modeling
AU: * Parotidis, M
EM: mparotid@geophysik.fu-berlin.de
AF: Geophysics Department - Freie Universitaet Berlin, Malteserstr. 74-100, Build. D, Berlin, 12249 Germany
AU: Rothert, E
EM: rothert@geophysik.fu-berlin.de
AF: Geophysics Department - Freie Universitaet Berlin, Malteserstr. 74-100, Build. D, Berlin, 12249 Germany
AU: Shapiro, S A
EM: shapiro@geophysik.fu-berlin.de
AF: Geophysics Department - Freie Universitaet Berlin, Malteserstr. 74-100, Build. D, Berlin, 12249 Germany
AB: Vogtland/NW-Bohemia (VB) at the German/Czech border region, central Europe, is characterized by recurring intraplate earthquake swarms, Quaternary volcanism, carbon-dioxide-rich mineral springs, a complex tectonic environment of intersecting fault systems, and an established connection between ascending magmatic fluids and seismicity. As the triggering mechanism of seismicity in VB is still unknown, this study aims to contribute by investigating the possible role of fluids in VB, based on the theory of linear poroelasticity. We assume that ascending fluids, of magmatic origin, trigger earthquakes by the mechanism of pore-pressure diffusion (i.e. relaxation). Two physical fields, the hydraulic diffusivity and the criticality (i.e. critical pore-pressure value leading to failure), both heterogeneously distributed in rocks, mainly control this triggering process. The results of the analysis of the year 2000 earthquake swarm data allowed the identification of diffusive characteristics, thus supporting this concept. It is further strengthened by a numerical model, with correlated high-diffusivity and high-criticality patches (corresponding to highly fractured and permeable compartments of the fault zone region in VB), which successfully simulates the general seismicity pattern of the earthquake swarms 2000, including the spatio-temporal clustering of the events, and the seismic activity migration.
DE: 7209 Earthquake dynamics and mechanics
DE: 7215 Earthquake parameters
DE: 7230 Seismicity and seismotectonics
DE: 7260 Theory and modeling
SC: Seismology [S]
MN: 2003 Fall Meeting