摘要
对覆盖同一地区的ASAR升降轨数据进行二通法差分干涉处理，获取2008年3月21日于田地震在两种LOS方向下干涉纹图。通过对干涉纹图的判读，结合震源机制解、地质构造和余震分布，认为于田地震断层为略有走滑分量的NE向正断层。考虑到于田地震的走滑分量微小的特定形变特点，在形变场三维解算中加入沿断层方向形变值近似为0的约束条件，结合已有的升降轨LOS方向形变约束，可以满足求解三维形变场的条件。解算的三维形变场结果表明，在雷达相干区域内．下盘抬升最高值达到15cm，上盘沉降最大值达到22cm，水平拉张的最大形变值出现在下盘，形变量达115cm，这说明于田地震拉张特征明显。该结果为进一步认识于田地震的同震变形特征提供参考。
We processed the ascending and descending ASAR data covering the same area by using two-pass D-InSAR method, and got interferograms in two different LOS directions of the Mar. 21, 2008 Yutian earthquake. Through interpretation of these interferograms, as well as the consideration of focal mechanism solutions, geologic structure and aftershock distributions, we held that the fault of Yutian earthquake is a kind of NE normal fault, while haveing a little striking component. In view of small component of striking deformation of the Yutian earthquake, we added a constraint condition that the deformation along the fault to be zero. As a result, we could fill the requirement of calculating 3D deformation by combining another two constraint conditions, the ascending LOS directional deformation and descending LOS directional deformation. Through analysis of the calculated 3D deformation field, we found that in the coherent area of radar image, the largest rising value of foot wall is 15cm, while the largest subsiding value of the upper wall amounted to 22cm. Meanwhile, the greatest tensile deformation is found in foot wall with the value of 115cm, which suggests that the extentional trend of Yutian earthquake is significant. These outcome could provide reference for further understanding of the Yutian co-seismic deformation.
出处
《地震》
CSCD
北大核心
2009年第B10期105-112,共8页
Earthquake
基金
地震动力学国家重点实验室（LED2008A06）、国家科技支撑计划（2008BAC35B04）、同家自然科学基金（40874006）项目共同资助
