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摘要
We present a three-dimensional (3-D) P-wave attenuation (Qp) model for the geodynamically active swarm earthquake area of West Bohemia/Vogtland in the Czech/German border region. Path-averaged attenuation t* is calculated from amplitude spectra of time windows around the P-wave arrivals of local earthquakes. Average t/t* value or Qp for stations close to Nov2 Kostel are very low (<150) compared to that of stations located further away from the focal zone (increases up to 500 within 80 km distance). The SIMUL2000 tomography scheme is used to invert the t* for P-wave attenuation perturbation. Analysis of resolution shows that our model is well-resolved in the vicinity of earthquake swarm hypocenters. The prominent features of the model are located around Novji Kostel focal zone and its northern vicinity. Beneath NovSi Kostel a vertically stretched (down to depth of 11 km) and a highly attenuating body is observed. We believe that this is due to fracturing and high density of cracks inside the weak earthquake swarm zone in conjunction with presence of free gas/fluid. Further north of Novr Kostel two highly attenuating bodies are imaged which could represent fluid channels toward the surface. The eastern anomaly shows a good correlation with the fluid accumulation area which was suggested in 9HR seismic profile.
- 出版日期2017-1-16
- 单位中国科学院地质与地球物理研究所
