气枪震源地震波走时变化影响因素分析及地震相关的走时变化

Influence Factors of Velocity Variation of Airgun Seismic Waves and Travel Time Changes Related to Earthquakes

云南省地震局在程海断裂以西10km的大银甸水库处建成了气枪震源发射台,在水库丰水期内进行连续激发观测。2014年8月21日、24日气枪震源附近分别发生MS4.2、ML4.1和ML4.0地震。本文利用宾川气枪震源附近的钟英台、黄坪台等10个台站2014年9月8日至2015年2月28日观测数据,使用波形互相关方法提取这些台站气枪信号的走时变化,使用射线追踪的方式正演研究了气压、水库水位、潮汐应力等因素对波速变化的影响。排除上述影响后,认为3次4级左右地震可能是2014年9月台站气枪信号走时增大0.04~0.05s的原因。

The Binchuan Earthquake Transmitting Seismic Station is located in Dayindian reservoir,which 10 kilometers west of the Chenghai Fault.There are 3 earthquakes with magnitude of MS4.2,ML4.1 and ML4.0 occurred around BETSS on 21 st and 24 th,August,2014.Data collected from 10 mobile seismic stations from 8 th,August,2014 to28 th,February,2015,are used to get travel time changes using waveform cross-correlation method.We calculated and analyzed influences of atmospheric pressure,water level of Dayindian reservoir and tidal stress on travel time changes using ray tracing method.After eliminating the effects of above factors,we deem that the possible reason of the increase of travel time in August 2018 is the the 3 earthquakes mentioned above.