Estimation of Source Rupture Process and Strong Ground Motion Simulation of the 2002 Denali, Alaska, Earthquake
Estimation of Source Rupture Process and Strong Ground Motion Simulation of the 2002 Denali, Alaska, Earthquake
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DOI：
10.1785/0120040154
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发表时间：
2005-10
影响因子：
3
通讯作者：
K. Asano;T. Iwata;K. Irikura
中科院分区：
文献类型：
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作者：
K. Asano;T. Iwata;K. Irikura
2002年11月3日22时12分（世界标准时间），阿拉斯加德纳里断裂带发生里氏7.9级内陆地壳地震。本文利用强震和全球定位系统（gps）测得的静态位移数据，通过多时间窗线性运动波形反演估算了2002年德纳里地震的震源过程。得到的震源模型可以解释观测到的强运动波形和gps测量到的静位移。在震源以东约80-90公里和150-200公里处观察到断层面上的大滑动。这些特征与观测到的地表破裂分布和其他利用远震体波反演的结果一致。我们还观察到整个断层的某些部分局部破裂传播速度超过4.0 km/s，超过了震源区的横波速度。断裂面积与地震矩的关系似乎遵循双线性L型标度，而非自相似震源标度。反演震源模型与地震矩的经验标度关系表明，凸起的组合面积比反演震源模型预测的要小。最后，我们利用有限差分法进行了前向地震动模拟，以估计本文得到的非均质源过程对强地震动空间分布的影响。由于单向破裂传播的正向方向性效应，计算得到的大滑动区上方和周围以及断裂带以东区域的地震动相对较大。
A M W 7.9 inland crustal earthquake occurred in the Denali fault system, Alaska, on 3 November 2002 at 22:12 (UTC). In this study, we estimated the source process of the 2002 Denali earthquake by a multiple time-window linear kinematic waveform inversion using strong motion and Global Positioning System (gps)-measured static displacement data. The obtained source model could explain both the observed strong motion waveforms and gps-measured static displacements. Large slips on the fault plane are observed at approximately 80–90 km and 150–200 km east from the hypocenter. These features are consistent with the observed surface rupture distribution and the other inversion results obtained using teleseismic body waves. We also observed some portions of the whole fault with a local rupture propagation velocity of more than 4.0 km/sec that exceeded the shear-wave velocity of the source region. The relation between the rupture area and seismic moment of this earthquake seems to follow the bilinear L -model scaling rather than the self-similar source scaling model. The combined area of asperities is somewhat smaller than that expected from the empirical scaling relationship with seismic moments developed by compiling inverted source models. Finally, we conducted a forward ground motion simulation using the finite difference method to estimate the influence of the heterogeneous source process obtained here on the spatial distribution of strong ground motions. The calculated ground motions are relatively large above and around the large slip areas and also in the region east of the fault area because of the forward directivity effect of unilateral rupture propagation.