Scaling Relations of Earthquake Source Parameter Estimates with Special Focus on Subduction Environment
Scaling Relations of Earthquake Source Parameter Estimates with Special Focus on Subduction Environment
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DOI：
10.1785/0120100111
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发表时间：
2010-12-01
影响因子：
3
通讯作者：
Scherbaum, Frank
中科院分区：
文献类型：
--
作者：
Blaser, Lilian;Krueger, Frank;Scherbaum, Frank
地震破裂的长度和宽度估计在许多地震学应用中都是需要的。地震震级估计通常是可用的，而破裂断层的几何扩展大多是缺乏的。因此，需要缩放关系从大小推导出长度和宽度。最常用的是Wells和Coppersmith（1994）的关系，该关系是基于一个大型数据集得出的，该数据集包括除俯冲环境中的逆冲断层事件外的所有滑动类型。然而，由于俯冲带具有高地震和海啸发生潜力，因此在处理地震方面有许多应用。对于俯冲事件，力矩大小和长度/宽度没有确定的标度关系。在这项研究中，我们编制了283次地震震源参数估计的大型数据库。所有震源机制都有描述，但特别关注（大型）俯冲带事件。采用线性最小二乘法和正交回归对尺度关系进行拟合，并对大陆与俯冲带/大洋关系的差异进行分析。此外，还检验了地震参数估计技术进步对标度关系的影响以及不同断层机制的影响。与Wells和Coppersmith（1994）相比，对于给定的力矩量级，我们发现冲断事件的破裂区域更短但更宽。发现纯大陆和纯俯冲带破裂区的逆冲事件关系几乎相同。不同滑移类型的标度关系差异显著。排除1964年世界标准地震台网建立之前的事件，对走滑尺度关系产生了显著影响：数据没有显示走滑地震的破裂宽度饱和。一般来说，破裂面积似乎与平均滑动无关，与震级无关。然而，纵横比L/W取决于力矩，并且每种滑移类型不同。
Earthquake rupture length and width estimates are in demand in many seismological applications. Earthquake magnitude estimates are often available, whereas the geometrical extensions of the rupture fault mostly are lacking. Therefore, scaling relations are needed to derive length and width from magnitude. Most frequently used are the relationships of Wells and Coppersmith (1994) derived on the basis of a large dataset including all slip types with the exception of thrust faulting events in subduction environments. However, there are many applications dealing with earthquakes in subduction zones because of their high seismic and tsunamigenic potential. There are no well-established scaling relations for moment magnitude and length/width for subduction events.Within this study, we compiled a large database of source parameter estimates of 283 earthquakes. All focal mechanisms are represented, but special focus is set on (large) subduction zone events, in particular. Scaling relations were fitted with linear least-square as well as orthogonal regression and analyzed regarding the difference between continental and subduction zone/oceanic relationships. Additionally, the effect of technical progress in earthquake parameter estimation on scaling relations was tested as well as the influence of different fault mechanisms.For a given moment magnitude we found shorter but wider rupture areas of thrust events compared to Wells and Coppersmith (1994). The thrust event relationships for pure continental and pure subduction zone rupture areas were found to be almost identical. The scaling relations differ significantly for slip types. The exclusion of events prior to 1964 when the worldwide standard seismic network was established resulted in a remarkable effect on strike-slip scaling relations: the data do not show any saturation of rupture width of strike- slip earthquakes. Generally, rupture area seems to scale with mean slip independent of magnitude. The aspect ratio L/W, however, depends on moment and differs for each slip type.