震源过程数字地震成像结果给出的地震参数定标律  

Scaling of Source Parameters from the Digital Imaging of Earthquake Rupture Process

作　　者：张雅君[1] 吴忠良[1] 蒋长胜[1] 

机构地区：[1]中国地震局地球物理研究所,北京民族大学南路5号100081

出　　处：《中国地震》2004年第4期330-340,共11页Earthquake Research in China

基　　金：国家自然科学基金资助项目 (项目号 :4 0 2 74 0 13)

摘　　要：震源参数的定标律在震源物理和地震灾害研究中具有重要作用。虽然用地表破裂也可以得到一个总体上的震源参数的定标律 ,但由此得到的定标律具有很大的局限性。例如2 0 0 1年印度古吉拉特MW 7 6地震在地表几乎看不到原生断层 ,而 2 0 0 1年中国西藏昆仑山MW7 8地震在地表的断层总长度可达 5 0 0多公里。宽频带数字地震学的发展 ,尽管在细节上还存在诸多问题 ,但已使地震学家有条件得到地震破裂过程的数字成像结果 ,这样的成像结果可以给出更为可靠的地震断层参数 ,比如地震断层长度和平均位错量等。基于这一进展 ,本文试图利用最近得到的数字地震成像结果 ,研究地震参数的定标律。为此 ,选择了 3个较为系统的数据集合 ,分别为D J.Wald收集和编辑的震源成像结果、Y .Yagi所做的震源过程成像结果和东京大学地震研究所 (ERI)的地震震源过程观测报告 ,共计 6 3次地震。结果表明 :如果考虑所有这些地震 ,则地震矩与断层长度之间近似满足M0 ∝L3 的关系 ;但如果仅考虑较大的地震 ,则走滑型地震接近满足M0 ∝L2 的关系 ,而非走滑型地震接近近满足M0 ∝L3 的关系。对走滑型地震 ,最大位错量Dmax与L和W这两个量中较小的量有明显的依赖关系 ,但非走滑型地震不具有这样的性质。Scaling relation of source parameters plays an important role in the physics of seismic source and the study of seismic hazard. Results from earthquake cases show that surface rupture, although being able to provide an overall scaling of source parameters, has significant limitations in some cases. For example, the 2001 Bhuj, India, M W 7.6 earthquake shows almost no original surface rupture, while the 2001 Kunlun Mountains pass, Tibet, China, M W 7.8 earthquake has an overall surface rupture up to 500 km. With the development of broadband seismology, it has been possible for seismologists to obtain the digital imaging of rupture process of earthquakes. Although being quite problematic in details, such imaging may give a reliable set of overall properties of earthquake faulting process such as the fault length and the average slip along the earthquake fault. Based on the recently published results of seismic rupture process from D. J. Wald, Y. Yagi,and ERI of Tokyo University, we choose 63 earthquakes for the analysis. The result shows that if we consider all the earthquakes, the relation between moment magnitude and fault length is close to M 0∝L 3, but for big earthquakes, the relation of strike-slip earthquakes are close to M 0∝L 2 while the relation of non-strike-slip earthquakes are close to M 0∝L 3. For strike-slip earthquakes, maximum slip has a clear dependence on the size of the earthquake fault, but non-strike-slip earthquakes do not show such a character.

关 键 词：震源过程 数字地震成像 地震参数定标律 地震矩 地震断层尺度 

分 类 号：P315[天文地球—地震学]