【摘要】 传统的微地震数据震源定位算法依赖于波至时间的拾取。由于微地震数据量较大且信噪比较低,手动拾取纵波和横波的波至时间很耗时,且引入的人为误差不易控制。笔者在分析已有方法特点的基础上,给出一种较快捷、准确的两步法微地震初至自动拾取方法。该方法首先使用时窗能量比法识别微震事件并大致确定波至时间,然后使用局部AIC精确拾取波至时间。与常规时窗能量比法相比,该方法减弱了时窗大小对拾取精度的影响;与常规的AIC法相比,由于只在局部使用AIC,避免了在低信噪比情况下AIC会出现多个局部极小从而难以准确拾取的问题,同时也提高了拾取效率。最后通过野外实际微地震数据进行了测试,分析了该方法的性能,验证了该方法的有效性和实用性。更多还原

【Abstract】 Determining an accurate first arrival time of P wave and S wave is very important in locating microseismic events,and manual picking is extremely time-consuming and subjective.An automatic two-step method based on after-term average over before-term average ratio(ATA/BTA) and the Akaike Information criterion(AIC) is developed.The ATA/BTA is used to detect the event and the AIC is utilized for picking.The method can attenuate the impact of window length and improve the precision of picking.The examination of the algorithm in different window lengths and various SNR environments by using the real data proves its effectiveness and practicability.更多还原