Extent, duration and speed of the 2004 Sumatra-Andaman earthquake imaged by the Hi-Net array
Extent, duration and speed of the 2004 Sumatra-Andaman earthquake imaged by the Hi-Net array
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DOI：
10.1038/nature03675
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发表时间：
2005-06-16
期刊：
影响因子：
64.8
通讯作者：
Vidale, JE
中科院分区：
文献类型：
--
作者：
Ishii, M;Shearer, PM;Vidale, JE
2004年12月26日苏门答腊岛-安达曼的灾难性地震是有记录以来最大的地震之一。这类地震的破坏潜力取决于断层滑动的程度和强度。第一次可靠的矩震级估计(1)是在苏门答腊岛-安达曼地震几个小时后获得的，但最近更长时间的正常模式分析表明，它有9.3级的矩震级，大约是2的2.5倍。在这里，我们介绍了一种直接成像地震破裂的方法，该方法利用第一到达的纵波，有可能在破裂开始后30分钟内产生详细的图像。我们使用日本的Hi-Net地震台阵作为天线，通过监测高频辐射的方向来绘制滑动的进程图。我们发现，破裂以约2.8公里S(-1)的速度向北传播约8分钟，覆盖了整个1300公里长的余震带。与其他大地震的余震区比较表明，苏门答腊岛-安达曼地震确实有类似9.3级的时刻震级。它的破裂，无论是持续时间还是程度，都是有记录以来最长的。
The disastrous Sumatra-Andaman earthquake of 26 December 2004 was one of the largest ever recorded. The damage potential of such earthquakes depends on the extent and magnitude of fault slip. The first reliable moment magnitude estimate(1) of 9.0 was obtained several hours after the Sumatra-Andaman earthquake, but more recent, longer-period, normal-mode analyses have indicated that it had a moment magnitude of 9.3, about 2.5 times larger(2). Here we introduce a method for directly imaging earthquake rupture that uses the first-arriving compressional wave and is potentially able to produce detailed images within 30 min of rupture initiation. We used the Hi-Net seismic array in Japan as an antenna to map the progression of slip by monitoring the direction of high-frequency radiation. We find that the rupture spread over the entire 1,300-km-long aftershock zone by propagating northward at roughly 2.8 km s(-1) for approximately 8 minutes. Comparisons with the aftershock areas of other great earthquakes indicate that the Sumatra-Andaman earthquake did indeed have a moment magnitude of similar to 9.3. Its rupture, in both duration and extent, is the longest ever recorded.