A unified analysis of crustal motion in Southern California, 1970–2004: The SCEC crustal motion map
A unified analysis of crustal motion in Southern California, 1970–2004: The SCEC crustal motion map
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DOI：
10.1029/2011jb008549
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发表时间：
2011-11
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影响因子：
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通讯作者：
Zheng‐Kang Shen;R. King;D. Agnew;M. Wang;T. Herring;D. Dong;P. Fang
中科院分区：
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作者：
Zheng‐Kang Shen;R. King;D. Agnew;M. Wang;T. Herring;D. Dong;P. Fang
为了确定南加州及其周边地区的地壳运动，我们对1970年至1992年收集的三边测量数据、1979年至1992年的VLBI数据和1986年至2004年的GPS数据进行了处理和组合：由于该地区发生了几次大地震，需要长时间的覆盖。从一系列台站位置的解中，我们估计了震间速度、同震位移和震后运动。在北纬31°至北纬38°的区域内。最终产品包括1009个GPS点、190个三边测量点和16个VLBI点的估计水平速度，其中一些点之间的联系用于稳定解决方案。所有的运动都是相对于稳定的北美参考系（SNARF），通过20个GPS站的速度实现。这提供了一个相对密集的水平速度估计集，具有经过良好测试的误差，在过去的25年里，在板块边界从31°N到36.5°N。这些速度与板块边界观测站的数据吻合得很好，后者适用于较晚的时间段。我们还估计了垂直速度，其中533个误差低于2毫米/年。这些速度大多小于1毫米/年，但在文图拉盆地和洛杉矶盆地以及索尔顿海槽，它们显示出2-4毫米/年的沉降。我们的分析还包括与1992年兰德斯地震、1994年北岭地震、1999年赫克托雷地震和2003年圣西蒙地震相关的同震和震后运动估计。震后运动随时间呈对数增长，时间常数约为10天，通常模拟同震偏移的方向和相对振幅。
[1] To determine crustal motions in and around southern California, we have processed and combined trilateration data collected from 1970 to 1992, VLBI data from 1979 to 1992, and GPS data from 1986 to 2004: a long temporal coverage required in part by the occurrence of several large earthquakes in this region. From a series of solutions for station positions, we have estimated interseismic velocities, coseismic displacements, and postseismic motions. Within the region from 31°N to 38°N. and east to 114°W, the final product includes estimated horizontal velocities for 1009 GPS, 190 trilateration, and 16 VLBI points, with ties between some of these used to stabilize the solution. All motions are relative to the Stable North American Reference Frame (SNARF) as realized through the velocities of 20 GPS stations. This provides a relatively dense set of horizontal velocity estimates, with well-tested errors, for the past quarter century over the plate boundary from 31°N to 36.5°N. These velocities agree well with those from the Plate Boundary Observatory, which apply to a later time period. We also estimated vertical velocities, 533 of which have errors below 2 mm/yr. Most of these velocities are less than 1 mm/yr, but they show 2–4 mm/yr subsidence in the Ventura and Los Angeles basins and in the Salton Trough. Our analysis also included estimates of coseismic and postseismic motions related to the 1992 Landers, 1994 Northridge, 1999 Hector Mine, and 2003 San Simeon earthquakes. Postseismic motions increase logarithmically over time with a time constant of about 10 days, and generally mimic the direction and relative amplitude of the coseismic offsets.