Using the theoretical model of coda scattering from local earthquakes, we have studied the features of time-space variations of the attenuation rate β of coda amplitude and coda Qc-1 values before and after the Qina ...Using the theoretical model of coda scattering from local earthquakes, we have studied the features of time-space variations of the attenuation rate β of coda amplitude and coda Qc-1 values before and after the Qina earthquakes (MS5.4 and MS5.1) in Dec. 1992 in West Yunnan Earthquake Prediction Study Area (WYEPSA). The study results show that the attenuation rate of coda amplitude has remarkable regional inhomogeneity in the near-field (△ 【50 km) around the main shock: β = 0.0076 s-1 and Qc-1 = 0.0056 during the main shock while (3 = 0.0209 s-1 and Qc-1 = 0.0153 during the aftershock. The Qc-1 value shows an approximate 3-foid variation before and after the main shock. We have also obtained the regional averages of β = 0.0235 s-1 and Qc-1 = 0.0153, which show that the coda attenuation in surrounding areas (△ 】 50 km) far away from the epicenter of the main shock did not change much before and after the main shock. The evolution of Qc-1 values of the main seismic sequence with time has passed展开更多
基金This project was sponsored by the Eighth Five-Year-Plan of SSB, China.
文摘Using the theoretical model of coda scattering from local earthquakes, we have studied the features of time-space variations of the attenuation rate β of coda amplitude and coda Qc-1 values before and after the Qina earthquakes (MS5.4 and MS5.1) in Dec. 1992 in West Yunnan Earthquake Prediction Study Area (WYEPSA). The study results show that the attenuation rate of coda amplitude has remarkable regional inhomogeneity in the near-field (△ 【50 km) around the main shock: β = 0.0076 s-1 and Qc-1 = 0.0056 during the main shock while (3 = 0.0209 s-1 and Qc-1 = 0.0153 during the aftershock. The Qc-1 value shows an approximate 3-foid variation before and after the main shock. We have also obtained the regional averages of β = 0.0235 s-1 and Qc-1 = 0.0153, which show that the coda attenuation in surrounding areas (△ 】 50 km) far away from the epicenter of the main shock did not change much before and after the main shock. The evolution of Qc-1 values of the main seismic sequence with time has passed