Abstract:〗This paper selects P, S wave arrival time difference Δt ≤ 14 s data, and calculates the Shanxi reservoir earthquake sequence seismic wave velocity using the multi-station method, combined with the characteristics of temporal and spatial distribution of seismic sequence and seismic structure. Analysis of the temporal and spatial distribution characteristics of wave velocity ratio sequence shows: 1) The seismic wave velocity ratio in Shanxi reservoir is 90% concentrated in 1.66-1.75, with an average velocity ratio of 1.70. 2) Shanxi reservoir earthquake sequence comprises a plurality of seismic activity. Each group of seismic velocity ratio starts by showing a rapid decline| after a phase of wave velocity ratio showing changes slowly rising. Wave velocity ratios between every two groups of earthquakes generally show a gradually increasing trend. Variation characteristics of wave velocity ratio in Shanxi reservoir earthquake sequence can be summarized as “drop-rebound-a group of earthquake”. 3) There is some relationship between the wave velocity changes and epicentral location. As the earthquake migrates to the new position, the initial several seismic wave velocity ratio is relatively large, and then the velocity ratio gradually reduces. 4) Along the depth direction and along the Shuangxi-Jiaoxiyang fracture direction, wave velocity distribution is not uniform. Wave velocity ratio is relatively small in the northwest segment of the Shuangxi-Jiaoxiyang fault submerged in the reservoir| wave velocity shows the most complex variation in the southeast segment of Shuangxi-Jiaoxiyang fracture. Located in the south bank of the reservoir, there are two transition regions of high value and low value wave velocity ratios. An ML≥4 earthquake occurred in the transition region at a 5-8 km depth.
ZHONG Yuyun,ZHANG Zhenfeng,KAN Baoxiang. The Temporal and Spatial Distribution Characteristics of Seismic
Wave Velocity Ratio in Shanxi Reservoir[J]. jgg, 2015, 35(5): 871-875.