New Velocity Structure of the NovyKostel Earthquake-Swarm Region, West Bohemia, Determined by the Isometric Inversion

0570947 - ÚSMH 2024 RIV CH eng J - Journal Article
Málek, Jiří - Brokešová, J. - Novotný, O.
New Velocity Structure of the NovyKostel Earthquake-Swarm Region, West Bohemia, Determined by the Isometric Inversion.
Pure and Applied Geophysics. Roč. 180, č. 6 (2023), s. 2111-2134. ISSN 0033-4553. E-ISSN 1420-9136
R&D Projects: GA MŠMT(CZ) LTAUSA19083
Institutional support: RVO:67985891
Keywords : Isometric inversion * West Bohemia * Vogtland * Earthquake swarm * Station corrections * Upper crust
OECD category: Geology
Impact factor: 2, year: 2022
Method of publishing: Limited access
https://doi.org/10.1007/s00024-023-03250-w

The intraplate West Bohemia region is characterized by relatively frequent earthquake swarms mostly concentrated in the vicinity of the NovyKostel village. Records of selected microearthquakes of the 2008 seismic swarm from a small circular area around NovyKostel with a radius of 11 km are processed with focus on availability of precise onset readings from all the selected events at all the selected stations. These data were used in the joint hypocenter-velocity inversion, employing the so-called isometric method which is especially efficient for this task. The results are two new one-dimensional velocity models, the constrained (smoother) and the unconstrained one, of the upper crust down to the depth of 11 km, and absolute locations of the selected earthquakes in the new constrained model. The foci delineate two segments of a steeply dipping fault zone. Time residuals at each of the stations display a remarkable azimuthal dependence, for both P and S waves, caused by anisotropy. No systematic dependence on epicentral distance was found even for stations outside the target area, which means that the new 1D models seem to be reasonable approximations of the real structure in the whole, much larger, West Bohemia region. No time dependence indicating possible changes of vP, vS and their ratio during the swarm was observed. A set of P-and S-wave station corrections that should be used to correct onset times in order to reach precise absolute locations was derived as an integral part of the new models.
Permanent Link: https://hdl.handle.net/11104/0346191