Source inversion of W phase: speeding up seismic tsunami warning
Source inversion of W phase: speeding up seismic tsunami warning
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DOI：
10.1111/j.1365-246x.2008.03887.x
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发表时间：
2008-10-01
影响因子：
2.8
通讯作者：
Rivera, Luis
中科院分区：
文献类型：
--
作者：
Kanamori, Hiroo;Rivera, Luis
W相是在S波之前到达的一个长周期相。它可以被解释为叠加的基本，第一，第二和第三泛音的球状模式或瑞利波，并有一个群速度为4.5至9公里秒（-1）的周期范围为100-1000秒。长周期波的振幅更好地代表了地震的海啸潜力。由于W相具有较快的群速度，因此大部分W相能量被包含在P波到达后的较短时间窗内。在50度的距离，W相能量包含在起源时间后的23分钟内，这是使用W相用于快速海啸预警目的的明显优势。本文采用时间域反褶积方法从全球地震台网的宽带记录中提取W震相。W相的带宽约为0.001 ~ 0.01Hz，在大多数情况下，我们对0.001 ~ 0.005Hz的数据进行带通滤波。从垂直分量记录中提取W相位后，我们使用点源进行线性反演，以确定M-w和几个大地震的震源机制，包括2004年苏门答腊-安达曼地震，2005年尼亚斯地震，2006年千岛群岛地震。2007年苏门答腊地震。W相位反转产生可靠的解决方案，并保持使用W相位的海啸潜力的快速评估的承诺。
W phase is a long period phase arriving before S wave. It can be interpreted as superposition of the fundamental, first, second and third overtones of spheroidal modes or Rayleigh waves and has a group velocity from 4.5 to 9 km s(-1) over a period range of 100-1000 s. The amplitude of long period waves better represents the tsunami potential of an earthquake. Because of the fast group velocity of W phase, most of W phase energy is contained within a short time window after the arrival of the P wave. At a distance of 50 degrees, W phase energy is contained within 23 min after the origin time which is the distinct advantage of using W phase for rapid tsunami warning purposes. We use a time domain deconvolution method to extract W phases from the broad-band records of global seismic networks. The bandwidth of W phase is approximately from 0.001 to 0.01 Hz, and we bandpass filter the data from 0.001 to 0.005 Hz in most cases. Having extracted W phase from the vertical component records, we perform a linear inversion using a point source to determine M-w and the source mechanism for several large earthquakes including the 2004 Sumatra-Andaman earthquake, the 2005 Nias earthquake, the 2006 Kuril Is. earthquake and the 2007 Sumatra earthquake. W phase inversion yields reliable solutions and holds promise of the use of W phase for rapid assessment of tsunami potential.