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苏门答腊—安达曼MW9.1级地震的破裂过程持续了大约500秒,这一时间几乎是一般情况下用于计算远震辐射能量的P到时和PP到时之间时间窗长度的两倍。为了测量整个地震所辐射的P波,我们将时间窗扩展为从P波到时到S波到时,并用扩展窗对震中距大于60°的台站的地震记录进行分析。这些持续时间8～10分钟的窗内包含了PP,PPP,ScP震相和其他一些多次反射震相。为了测量包含这些附加震相的影响,我们计算了由扩展窗(P波到时和S波到时之间)得到的震源谱和由标准窗(P波到时和PP波到时之间)得到的震源谱的比值。对扩展窗的分析是在假设它只包含P-pP-sP波群的情况下进行的。我们分析了发生在MW9.1级主震附近具有相似深度和震源机制的4个相对较小的地震事件。这些地震的震级范围从2005年1月9日的MW6.0级余震到震中位于苏门答腊-安达曼地震南部的2005年3月28日MW8.6级的尼亚斯地震。将得到的这4个地震事件的震源谱比值取平均,就得到扩展窗的频变算子。然后对扩展窗得到的2004年12月26日主震的震源谱进行校正,就得到苏门答腊-安达曼地震整个破裂过程(～600秒)的完整的或校正的震源谱。我们计算的地震辐射总能量为1.4×1017J。经过对整个地震的校正震源谱与破裂过程的前～250秒的震源谱(由标准远震窗得到)比较,我们发现主震破裂过程的前半部分辐射的地震波能量多于破裂过程后半部分辐射能量,尤其对于周期从3秒到40秒的地震波,这种现象更加明显。
The rupture of the Sumatra-Andaman MW9.1 earthquake lasted about 500 seconds, almost double the P-time and PP-to-time window length used to calculate teleseismic radiation energy under normal conditions. In order to measure the P wave radiated by the entire earthquake, we extend the time window from P wave arrival to S wave arrival time and analyze the seismic records of stations with epicenter distances greater than 60 ° with extended windows. These windows, lasting eight to ten minutes, contain the PP, PPP, ScP phases and several other multi-reflection phases. In order to measure the effects of the inclusion of these additional phases, we calculated the source spectra from the extended window (P-wave to S-wave-to-peak) and the source spectra from the standard window (P-wave to time and PP wave-to- The resulting source spectrum ratio. The analysis of the extended window is done assuming that it contains only P-pP-sP clusters. We analyze four relatively small earthquakes that have similar depths and focal mechanisms near the MW9.1 mainshock. These earthquakes range in magnitude from the Mw 6.0 magnitude aftershock on January 9, 2005 to the Nias Earthquake magnitude MW8.6 on March 28, 2005, in the epicenter south of the Sumatra-Andaman Earthquake. By averaging the source spectral ratios of the four seismic events obtained, the frequency-dependent operators of the extended window are obtained. Correcting the focal source spectra of the December 26, 2004 mainshock resulting from the extended window gives a complete or corrected source spectrum for the entire rupture (~ 600 seconds) of the Sumatra-Andaman Earthquake. We calculate the total energy of seismic radiation 1.4 × 1017J. After comparing the source spectrum of the entire earthquake with the source spectrum of the first ~ 250 seconds (obtained from the standard teleportation window), we find that the first half of the main shock ruptures have more seismic energy than the second half of the rupture process Energy, especially for seismic waves with periods from 3 seconds to 40 seconds, is even more pronounced.