Estimation of High-frequency Wave Radiation Areas on the Fault Plane of the 1995 Hyogo-ken Nanbu Earthquake by the Envelope Inversion of Acceleration Seismograms
Estimation of High-frequency Wave Radiation Areas on the Fault Plane of the 1995 Hyogo-ken Nanbu Earthquake by the Envelope Inversion of Acceleration Seismograms
复制标题
利用加速地震图包络反演估算1995年兵库县南部地震断层面高频波辐射区域
DOI：
10.4294/jpe1952.44.505
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
M. Hoshiba
中科院分区：
文献类型：
--
作者：
Y. Kakehi;K. Irikura;M. Hoshiba
利用强震加速度记录的包络线反演方法，对1995年兵库县南部地震（MJMA=7.2）的断层面高频波辐射过程进行了估计，该地震是一个沿内陆活动断层沿着走滑的地震。辐射高频（2-10 Hz）波的区域的水平范围约为45 km，这与根据强震位移波形反演估计的震源区相匹配。高频波主要辐射在这个源区域的外围，而在中心看到一个明显的辐射间隙。沿着野岛断层，高频和低频波辐射都很大。这是因为断裂破坏了这里的地表。在淡路岛和科比地区之间的断层阶跃处也辐射出高频波。台阶被解释为表现为一个几何障碍，并在破裂时产生高频波。从震源到科比东北部的高频波辐射在位移波形反演估计的大力矩释放区较小，在其外围较大。这表明，这些高频波停止相位从子事件对应的大力矩释放区。高频波源区域的范围大致与严重受损区域的范围相匹配。我们推断，直接来自震源的强高频波是造成低层建筑物严重破坏的原因之一。
We estimated the high-frequency wave radiation process on the fault plane of the 1995 Hyogo-ken Nanbu earthquake (MJMA=7.2), which was a strike slip event along active inland faults, by the envelope inversion of strong-motion acceleration seismograms. The horizontal extent of the region that radiated high-frequency (2-10 Hz) waves is about 45 km, which matches the source region estimated from the inversion of strong-motion displacement waveforms. High-frequency waves were mainly radiated at the periphery of this source region, while a clear gap of radiation was seen in the center. Along the Nojima fault, both high- and low-frequency wave radiation were large. This is explained by the fact that the rupture broke the ground surface here. Highfrequency waves were also radiated at the step-over of faults between Awaji Island and the Kobe area. The step-over is interpreted to have behaved as a geometrical barrier and generated high-frequency waves when ruptured. The radiation of high-frequency waves in the northeastern part from the hypocenter to Kobe was small in the large moment release areas estimated from the displacement waveform inversion, and large at their peripheries. This suggests these high-frequency waves were stopping phases from the subevents corresponding to the large moment release areas. The extent of the source region of high-frequency waves roughly matches that of the heavily damaged areas. We inferred that the strong high-frequency waves that came directly from the source was one of the causes of the heavy damage to low-rise structures.