Total Variation Regularization of Geodetically Constrained Block Models in Southwest Taiwan
Total Variation Regularization of Geodetically Constrained Block Models in Southwest Taiwan
复制标题
台湾西南地区大地测量约束块体模型的全变差正则化
DOI：
--
复制
发表时间：
2019
期刊：
影响因子：
--
通讯作者：
E. L. Evans
中科院分区：
文献类型：
--
作者：
Mong‐Han Huang;E. L. Evans
欧亚板块和菲律宾海板块之间的快速会聚使台湾成为世界上最活跃的构造区域之一，这种应变被容纳在复杂的逆冲断层和走滑断层网络中。本研究利用升、降向干涉合成孔径雷达（干涉合成孔径雷达）资料，结合连续GPS量测，监测台湾西南部震间形变。大地测量观测显示，台湾南部屏东平原有快速（20-40毫米/年）的西南运动，而西部山麓南部则有超过10毫米/年的隆升。本文利用2004 - 2010年的干涉合成孔径雷达和CGPS联合观测数据，对水平地震间地壳形变进行了块体约束。总变差正则化（TVR）作为块体模型选择的工具，基于大地测量观测值对块体模型几何形状进行算法评估，同时估计块体旋转和块体边界断层上的断层滑动速率。块体模型的结果表明，西部山麓的边缘容纳了台湾西南部大部分的地震间变形。需要35个独立的区块来解释地震间地壳变形，平均剩余速度为3.6 mm/年。在此水平模型的基础上，我们对垂直位移进行了正演预测，并发现预测的隆升与大地测量观测结果具有良好的一致性。我们的方法显示了一个有效的和客观的方法来估计断层活动和地震危险性的基础上密集的大地测量和它们的不确定性在地震间隔期。
Rapid convergence between the Eurasian plate and the Philippine Sea Plate makes Taiwan one of the most active tectonic regions in the world, and this strain is accommodated on a complex network of thrust and strike‐slip faulting. Here, we use ascending and descending Interferometric Synthetic Aperture Radar (InSAR) data integrated with continuous GPS measurements to monitor interseismic deformation in southwest Taiwan. Geodetic observations show rapid (20–40 mm/year) southwestward motion in the Pingtung plain in south Taiwan and more than 10 mm/year uplift in the southern part of the Western Foothills. We use combined InSAR and CGPS measurements from 2004 to 2010 to constrain a block model of horizontal interseismic crustal deformation. Total variation regularization (TVR) serves as a tool for block model selection to algorithmically assess the block model geometry based on geodetic observations, simultaneously estimating block rotations and fault slip rates on block‐bounding faults. The block model results suggest that the margins of the Western Foothills accommodate most of the interseismic deformation in southwestern Taiwan. Thirty‐five independent blocks are required to explain interseismic crustal deformation with a mean residual velocity of 3.6 mm/year. Based on this horizontal model, we then forward predict vertical displacement and find good consistency between the predicted uplift and the geodetic observations. Our approach shows an efficient and objective way to estimate fault activities and seismic hazards in the interseismic period based on dense geodetic measurements and their uncertainties.