刘建国教授讲座通知

报告名称：Modelling of Yingxiu–Beichuan fault zone based on refined DInSAR data of 2008 Wenchuan earthquake “根据2008汶川地震差分雷达相干数据所推导的映秀-北川断裂带模型”

报告时间：2015年4月22日15:00-16:30

报告地点：新实验楼211室（珙桐园对面）

授课人介绍：

刘建国博士，英国帝国理工大学地球科学工程系教授（Reader in Remote Sensing）。1988年公派前往英国帝国理工大学攻读博士学位，后留校工作至今。目前主要研究领域包括：相位相关亚像元影纹错位分析技术及其图像精确配准，高精度低屏蔽数字高程模型生成，隐蔽动目标探测和速度测量方面的应用；雷达相干技术和多数据地理信息模型用于地质灾害评估和地球新构造活动带研究。从事遥感图像处理和地球科学应用研究多年，刘建国博士设计开发了许多简单新颖有效的图像处理方法，被国际上主流图像处理系采用，在遥感界得到广泛应用。

讲座描述：

Differential interferometric synthetic aperture radar (DInSAR) provides an essential constraint for forward modelling of seismic faulting. However, the crucial evidence of deformation along the very near vicinity of a seismic fault is often missing because chaotic ruptures destroy the InSAR signal coherence; such is the case of the Yingxiu–Beichuan fault zone of the 2008 Wenchuan earthquake. We developed an Adaptive Local Kriging (ALK) interpolation method to produce a refined DInSAR dataset which continues without the interruption of decoherence gaps. Thus the 3D configuration of the seismic faulting can be better constrained for forward modelling using the Poly3D software. Through parameter fine tuning in a sequence of trial and error simulation, the best fitting between the simulated interferogram and the ALK refined DInSAR interferograms is achieved using a structural model of the Yingxiu–Beichuan fault zone which comprises a total of 14 segments with dip angles varying from 20° to 60°, in the south-west, to 40° to 70°, in the north-east; some major fault segments are composed of multiple planes with varying dip angles. The model reveals that in the much disputed Beichuan–Pengguan area, the Yingxiu–Beichuan fault links with the Pengguan fault (which dips to the NW at ~30°) at a depth of ~13 km. These two structures are interpreted as representing the foreland propagation of the Yingxiu–Beichuan fault by footwall collapse, a process that, in the vicinity of the Pengguan fault, involves the transfer of displacement from the older, Yingxiu–Beichuan fault to the younger Pengguan fault.