Topographic and seismic effects of long-term coupling between the subducting and overriding plates beneath Northeast Japan
Topographic and seismic effects of long-term coupling between the subducting and overriding plates beneath Northeast Japan
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日本东北部俯冲板块和上覆板块之间长期耦合的地形和地震效应
DOI：
10.1016/s0040-1951(96)00158-8
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发表时间：
1997
期刊：
影响因子：
2.9
通讯作者：
J. A. Snoke
中科院分区：
文献类型：
--
作者：
S. Huang;I. Sacks;J. A. Snoke
至少五百万年来，俯冲太平洋板块的运动一直在大致垂直于日本东北部岛弧走向的方向上稳定。我们已经证明，假设构造挤压驱动力和合理的地壳流变性，并使用允许粘滑断裂、侵蚀/沉积和随时间变化的载荷的有限元模拟程序，可以成功地模拟现今的地形、重力和地震活动模式。在本文中，我们展示了板间耦合的深度和沿走向的强度如何受到观测地形和重力的限制，并研究了耦合与观测的板间和板内地震活动的相关性。东部沿海地区的地形和重力残差异常在区域1(北上岭和三陆附近)明显高于区域2(宫城附近)。为了与观测到的地形和重力相匹配，区域1的板间耦合强度大约是区域2的两到四倍，在更深的地方有大约两倍的耦合强度。区域1和区域2的耦合被认为是两种极端情况。在区域3(Abukuma山脉和福岛附近)，耦合强度介于区域1和区域2之间。模型预测，耦合较强的区域1在地壳和地幔楔形顶端发生地震的可能性较高，这与观测到的板内地震活动相一致。观测到的板间地震活动模式也与板间耦合的差异相一致；2区的耦合较弱，表明缺乏孕震潜力，这导致该地区发生大地震的可能性很低。
For at least five million years, the motion of the subducting Pacific plate has been steady in a direction approximately perpendicular to the strike of the island arc in northeast Japan. We have shown that the present-day topography, gravity and seismicity patterns can be modeled successfully by assuming an approximately steady tectonic compressive driving force and a plausible crustal rheology and by using a finite element modeling code which allows stick-slip faulting, erosion/deposition and time-dependent loading. In this paper we show how the strength of interplate coupling with depth and along strike is constrained by the observed topography and gravity, and we examine the correlation of coupling with observed interplate and intraplate seismicity. Topography and the gravity residual anomaly in the eastern coastal area are significantly higher in region 1 (the Kitakami range and off Sanriku) than in region 2 (off Miyagi). In order to match the observed topography and gravity, the strength of interplate coupling in region 1 is about two to four times greater than in region 2, and there is about twice as strong a coupling at greater depths. Coupling in region 1 and region 2 are considered as two extreme cases. In region 3 (the Abukuma range and off Fukushima), the coupling strength is between that of region 1 and region 2. The model predicts a higher potential for earthquakes in the crust and mantle wedge apex for the region with stronger coupling, region 1, which is consistent with the observed intraplate seismicity. Observed patterns of interplate seismicity are also consistent with differences in interplate coupling; the weaker coupling in region 2 indicates a lack of seismogenic potential which leads to a low probability for large earthquakes in that region.