Comparison of the coseismic rupture with the aftershock distribution in the Hyuga‐nada Earthquakes of 1996
Comparison of the coseismic rupture with the aftershock distribution in the Hyuga‐nada Earthquakes of 1996
复制标题
1996年日向滩地震同震破裂与余震分布比较
DOI：
10.1029/1999gl005340
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发表时间：
1999
影响因子：
5.2
通讯作者：
T. Sagiya
中科院分区：
文献类型：
--
作者：
Y. Yagi;M. Kikuchi;S. Yoshida;T. Sagiya
1996年10月19日，在日本南开海槽南端发生了一次大型逆冲地震（Ms = 6.7）。大约两个月后，邻近地区发生了第二次大地震（震级6.7）。研究了日贺那达地区两次大地震的震源过程，并比较了同震破裂区和余震分布。第一次主震的主要震源参数为：（走向，倾角，前倾角）=（210°，12°，81°）；地震矩Mo = 2.3×1019 Nm (Mw = 6.8)；破裂面积S = 20 × 15 km²，震源持续时间T = 17 S。对于第二个主冲击，（走向，倾斜，前倾）=（210°，12°，87°）；地震矩Mo = 1.5×1019 Nm (Mw = 6.7)；破裂面积S = 18 × 18 km²，震源持续时间T = 15 S。同震破裂区与余震区不重叠，而两个主震的余震区相互重叠。这意味着共同余震区对动态破裂起着屏障的作用。从图中还可以看出，余震区域在第一天就扩大了。
On October 19, 1996, a large underthrusting earthquake (Ms = 6.7), the Hyuga‐nada, Japan, earthquake occurred along the southern end of Nankai trough. About two months later, a second large earthquake (Ms = 6.7) occurred in the adjacent region. We study the source process of the two large earthquakes in the Hyuga‐nada region and compare the coseismic rupture area with aftershock distribution. The main source parameters obtained for the first mainshock are: (strike, dip, rake)= (210°, 12°, 81°); the seismic moment Mo = 2.3×1019 Nm (Mw = 6.8); the rupture area S = 20 × 15 km², and the source duration T = 17 s. For the second main‐shock, (strike, dip, rake) = (210°, 12°, 87°); the seismic moment Mo = 1.5×1019 Nm (Mw = 6.7); the rupture area S = 18 × 18 km², and the source duration T = 15 s. The coseismic rupture areas do not overlap the aftershock area, while the aftershock areas of the two main‐shocks mutually overlap. This implies that the common aftershock region takes a role of barriers to dynamic rupture. It is also seen that the aftershock area expanded during the first one day.