Crustal deformation and surface kinematics after the 2010 earthquakes in Latin America
Crustal deformation and surface kinematics after the 2010 earthquakes in Latin America
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DOI：
10.1016/j.jog.2016.06.005
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发表时间：
2016-12-01
影响因子：
2.3
通讯作者：
Drewes, H.
中科院分区：
文献类型：
--
作者：
Sanchez, L.;Drewes, H.
强烈地震引起大地基准站的站位置和速度的巨大变化;即，全球ITRF（国际地球参考框架）及其区域密集化，如拉丁美洲和加勒比地区的SIRGAS（美洲地心参考系统）。为了确保大地参照框架的长期稳定性，不同时期之间台站位置的转换需要计算可靠的连续地表变形（或速度）模型。本文介绍了一个新的拉丁美洲和加勒比大陆连续地壳形变模型的计算，该模型是根据2010年智利和墨西哥发生强震后获得的GNSS（GPS + GLONASS）测量结果推断的。它是基于一个多年期速度解决方案，适用于456个连续运行的全球导航卫星系统台站网络，涵盖2010年3月14日至2015年4月11日的五年期。这种新的变形模型称为VEMOS 2015（SIRGAS 2015的速度模型），使用最小二乘配置（LSC）方法和经验确定的协方差函数进行计算。结果总结如下：虽然下加利福尼亚地震的影响可以被认为是局部的，但马乌莱地震的影响改变了大面积区域的表面运动学（从太平洋到大西洋海岸的纬度30度S-45度S之间）。马乌莱地震前，该区应变率场表现为强烈的东西向挤压，最大应变率约为0.40 μ应变/a，位于南纬38 ° ~ 44 °之间。相应地，变形矢量大致平行于板块俯冲方向，其大小随着距离俯冲前缘的距离而减小。震后最大挤压（0.25 μ应变/a）发生在南纬37 ° ~ 40 °之间，方向为N30 ° E。最大拉伸应变速率（0.20-0.35 μ应变/a）出现在南纬40度以南的巴塔哥尼亚亚安第斯带。伸展轴从Araucania区中部的N30 ° E方向旋转到巴塔哥尼亚西部的N72 ° W的西风方向。在平行南纬35度的北方地区，延伸也指向马乌莱区（南纬45度），但速度相当小（
Strong earthquakes cause large changes in the station positions and velocities of the geodetic reference stations; i.e., the global ITRF (International Terrestrial Reference Frame) and its regional densifications like SIRGAS (Sistema de Referenda Geocentric para Las Americas) in Latin America and the Caribbean. To ensure the long-term stability of the geodetic reference frames, the transformation of station positions between different epochs requires the computation of reliable continuous surface deformation (or velocity) models. This paper presents the computation of a new continental continuous crustal deformation model for Latin America and the Caribbean inferred from GNSS (GPS + GLONASS) measurements gained after the strong earthquakes occurred in 2010 in Chile and Mexico. It is based on a multi-year velocity solution for a network of 456 continuously operating GNSS stations and covering a five years period from March 14, 2010 to April 11, 2015. This new deformation model, called VEMOS2015 (Velocity Model for SIRGAS 2015), is computed using the least square collocation (LSC) approach with empirically determined covariance functions. The result is summarised as follows: While the effects of the Baja California earthquake can be considered as local, the effects of the Maule earthquake changed the surface kinematics of a large area (between the latitudes 30 degrees S-45 degrees S from the Pacific to the Atlantic coasts). Before the Maule earthquake, the strain rate field in this area showed a strong west-east compression with maximum rates of about 0.40 mu strain/a between latitudes 38 degrees S and 44 degrees S. In accordance, the deformation vectors were roughly parallel to the plate subduction direction and their magnitudes decreased with the distance from the subduction front. After the earthquake, the largest compression (0.25 mu strain/a) occurs between the latitudes 37 degrees S and 40 degrees S with a N30 degrees E direction. The maximum extensional strain rate (0.20-0.35 mu strain/a) is observed in the Sub-Andean zone in the Patagonia south of latitude 40 degrees S. The extensional axes rotate from a N30 degrees E direction in the central Araucania zone to a westerly direction of N72 degrees W in the western part of Patagonia. In the northern region of parallel 35 degrees S, the extension is also directed to the Maule zone (S45 degrees W) but with quite smaller rates (