Fault parameters determined by near- and far-field data: The Wakasa Bay earthquake of March 26, 1963
Fault parameters determined by near- and far-field data: The Wakasa Bay earthquake of March 26, 1963
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由近场和远场数据确定的断层参数：1963 年 3 月 26 日若狭湾地震
DOI：
10.1785/bssa0640051369
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发表时间：
1974
影响因子：
3
通讯作者：
K. Abe
中科院分区：
文献类型：
--
作者：
K. Abe
本文根据地震学资料，研究了1963年3月26日日本本州岛西海岸附近若狭湾地震（M = 6.9，35.80°N，135.76°E，深度4km）的震源过程。通过直接比较合成地震记录与近、远距离观测地震记录，确定断层的动、静态参数。采用De Hoop-Haskell方法进行合成。平均错位为60 cm。总位错速度估计为30 cm/sec，滑移位错的上升时间确定为2 sec。确定的其他断层参数，以及P波初动、S波偏振角和余震的补充资料为：震源几何形状，倾向N144 °E，倾角68°，滑动角22°（右旋走滑运动，带有一些倾滑分量）;断层尺寸，20 km长，8 km宽;破裂速度，2.3 km/sec（双侧）;地震矩，3.3 × 1025达因-厘米;应力降，32巴。据估计，加速断层运动的有效应力约为40巴。有效应力和应力降之间的近似一致性表明，大部分有效应力在地震发生时被释放。
The source process of the Wakasa Bay earthquake (M = 6.9, 35.80°N, 135.76°E, depth 4 km) which occurred near the west coast of Honshu Island, Japan, on March 26, 1963, is studied on the basis of the seismological data. Dynamic and static parameters of the faulting are determined by directly comparing synthetic seismograms with observed seismograms recorded at seismic near and far distances. The De Hoop-Haskell method is used for the synthesis. The average dislocation is determined to be 60 cm. The overall dislocation velocity is estimated to be 30 cm/sec, the rise time of the slip dislocation being determined as 2 sec. The other fault parameters determined, with supplementary data on the P-wave first motion, the S-wave polarization angle, and the aftershocks, are: source geometry, dip direction N 144°E, dip angle 68°, slip angle 22° (right-lateral strike-slip motion with some dip-slip component); fault dimension, 20 km length by 8 km width; rupture velocity, 2.3 km/sec (bilateral); seismic moment, 3.3 × 1025 dyne-cm; stress drop, 32 bars. The effective stress available to accelerate the fault motion is estimated to be about 40 bars. The approximate agreement between the effective stress and the stress drop suggests that most of the effective stress was released at the time of the earthquake.