Co-seismic surface deformation of the 2011 off the Pacific coast of Tohoku Earthquake: Spatio-temporal EOF analysis of GPS data
Co-seismic surface deformation of the 2011 off the Pacific coast of Tohoku Earthquake: Spatio-temporal EOF analysis of GPS data
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DOI：
10.5047/eps.2011.07.002
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发表时间：
2011-09
期刊：
影响因子：
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通讯作者：
E. Chang;B. Chao
中科院分区：
文献类型：
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作者：
E. Chang;B. Chao
2011年3月11日，日本太平洋沿岸的东北(本州东北部)遭遇了由近海9.0级大地震引发的强烈海啸。采用经验正交函数(EOF)分析方法，对日本GeoNet密集、连续的GPS数据进行了分析，得到并详细研究了日本本州岛三维同震和近震地表形变的时空行为。在主导形变发生的本州岛北部，同震水平位移和震后松弛向东-东南方向发展，最大振幅近4m。垂直分量在本州东侧向震中下沉达50厘米，但向西略有抬升。EOF解还在约20厘米的水平上探测到明显的震后松弛，其形变模式基本相同，但在主震后的几个小时到几天内幅度更大，以及一些主要前震/余震的(3-D)信号。从EOF解得到的同震水平应变场显示了一种有趣的空间模式，这为更好地理解该地区的动态和复杂的地震构造提供了进一步的洞察。
On March 11, 2011, Japan’s Pacific coast of Tohoku (northeast Honshu) was hit by a strong tsunami set off by a large off-shore magnitude 9.0 earthquake. We employ the method of empirical orthogonal function (EOF) analysis on the dense, continuous GPS data from Japan’s GEONET to obtain and examine in detail the spatiotemporal behavior of the 3-D co-seismic and near co-seismic surface deformation of Japan’s island of Honshu. For northern Honshu, where the dominant deformation occurred, the co-seismic horizontal displacement and the post-seismic relaxation were toward the east-southeast with a maximum amplitude of nearly 4 meters. The vertical component experienced a subsidence of up to 50 cm on the east side of Honshu toward the epicenter but with a slight uplift to the west. The EOF solutions also detect clear post-seismic relaxation on the ~20 cm level, of essentially the same deformation pattern but with a larger extent during the hours to days after the mainshock, as well as (3-D) signals from some of the major foreshocks/aftershocks. The co-seismic horizontal strain field derived from the EOF solutions exhibits an interesting spatial pattern that provides further insight towards better understanding of the dynamic and complex seismotectonics of the region.