用经验格林函数方法从红山地震台数字化资料提取隆尧地震的震源时间函数
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摘要
2002年4月22日在邢台老震区隆尧县境内发生了一次ML4.8地震,这次地震邢台地区震感强烈,随后又发生15次小的余震。我们从这些余震中任意选择了5次余震分别作经验格林函数,提取了该地震的震源时间函数,目的是从这个地震来反映邢台震区的地质构造和震源情况。结果表明:无论以哪次余震的记录作为经验格林函数,结果都相当一致。发生于2002年4月22日的ML4.8地震只是老震区断层的单次破裂,此次事件的持续时间较短,只有0.7s左右,上升时间约为0.5s。为了验证所提取的震源时间函数的稳定性和可靠性,作者用5个小余震的UD,EW,NS方向分别作经验格林函数处理,结果相当一致;同时用全波、P波和SH波进行提取震源时间函数的对比,结果表明,用全波和SH波效果较好,所得结果非常一致,而用P波提取的震源时间函数效果不很理想。即同一台站的不同震相求得的震源时间函数的幅度存在差异。
A M_L 4.8 earthquake occurred at Longyao, in Xingtai seismic zone, on April 22, 2002. The seismic esthesia is strong on Xingtai area. 15 little aftershocks occurred subsequently. Choosing 5 aftershocks randomly as experiential Green′s function, we draw focus time function of the main shock for the purpose of studying the geological structure and focus situation of Xingtai seismic zone. We found that the time functions we obtained are similar no matter which aftershock is chosen to be experiential Green′s function. The result indicates that the M_L 4.8 earthquake on April 22, 2002 is only a single break of the fault of old seismic zone with relatively short, about 0.7 s, duration time and about 0.5 s rise time. To verify the stability and dependability of function of focus time, we use the UD、EW and NS component digital records of 5 aftershocks as experiential Green′s function, respectively, and get the unanimous results. We also compare the time functions obtained with P, SH or whole waveform data, respectively, and find that the time functions obtained with SH and whole waveform are coherent, while the time function obtained from P waveform data is different in amplitude.
A M_L 4.8 earthquake occurred at Longyao, in Xingtai seismic zone, on April 22, 2002. The seismic esthesia is strong on Xingtai area. 15 little aftershocks occurred subsequently. Choosing 5 aftershocks randomly as experiential Green′s function, we draw focus time function of the main shock for the purpose of studying the geological structure and focus situation of Xingtai seismic zone. We found that the time functions we obtained are similar no matter which aftershock is chosen to be experiential Green′s function. The result indicates that the M_L 4.8 earthquake on April 22, 2002 is only a single break of the fault of old seismic zone with relatively short, about 0.7 s, duration time and about 0.5 s rise time. To verify the stability and dependability of function of focus time, we use the UD、EW and NS component digital records of 5 aftershocks as experiential Green′s function, respectively, and get the unanimous results. We also compare the time functions obtained with P, SH or whole waveform data, respectively, and find that the time functions obtained with SH and whole waveform are coherent, while the time function obtained from P waveform data is different in amplitude.
引文
许力生,陈运泰.1996.用经验格林函数方法从长周期波形资料中提取共和地震的震源时间函数[J].地震学报,18(2):156~169
许力生,陈运泰.1997.用数字化宽频带波形资料反演共和地震的震源参数[J].地震学报,19(2):113~128
周家玉,陈运泰,倪江川等.1993.用经验格林函数确定中小地震的震源时间函数[J].地震学报,15(1):22~31
许力生,陈运泰.1997.用数字化宽频带波形资料反演共和地震的震源参数[J].地震学报,19(2):113~128
周家玉,陈运泰,倪江川等.1993.用经验格林函数确定中小地震的震源时间函数[J].地震学报,15(1):22~31
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