Rupture History of the 2008 Mw 7.9 Wenchuan, China, Earthquake: Evaluation of Separate and Joint Inversions of Geodetic, Teleseismic, and Strong-Motion Data
Rupture History of the 2008 Mw 7.9 Wenchuan, China, Earthquake: Evaluation of Separate and Joint Inversions of Geodetic, Teleseismic, and Strong-Motion Data
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DOI：
10.1785/0120120108
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发表时间：
2013-02-01
影响因子：
3
通讯作者：
Mooney, Walter
中科院分区：
文献类型：
--
作者：
Hartzell, Stephen;Mendoza, Carlos;Mooney, Walter
一个广泛的数据集的地震和强震波形和大地偏移是用来研究2008年汶川，中国，地震的破裂历史。一个线性多时间窗的方法是用来参数化的破裂。由于汶川断裂的复杂性，三个独立的平面被用来代表破裂面。这次地震清楚地表明了大地测量、地震和强震数据集的优势和局限性。大地测量数据（静态偏移）对于确定较浅滑动的分布是有价值的，但对较深的断层不敏感，也不能揭示滑动的时间。在30度-90度距离范围内的遥测数据通常不涉及建模困难，因为简单的射线路径，并且可以区分浅滑和深滑。然而，当涉及多个断层面时，遥测数据不能区分不同的滑动情况，因为陡峭的起飞角导致时间上的模糊性。另一方面，局部强震数据是从方向性确定破裂方向的理想方法，但很容易用不准确的绿色函数过度建模，导致对滑移分布的误解。我们表明，所有三个数据集需要给汶川破裂的准确描述。力矩估计约为1.0 x 10（21）N.m，滑移特征为多个大斑块，滑移高达10 m。破裂始于彭关断层南端，并单向向东北方向进行。当到达横穿小鱼洞断层时，邻近的北川断层在此交界处开始破裂，并向东北和西南方向双向行进。
An extensive data set of teleseismic and strong-motion waveforms and geodetic offsets is used to study the rupture history of the 2008 Wenchuan, China, earthquake. A linear multiple-time-window approach is used to parameterize the rupture. Because of the complexity of the Wenchuan faulting, three separate planes are used to represent the rupturing surfaces. This earthquake clearly demonstrates the strengths and limitations of geodetic, teleseismic, and strong-motion data sets. Geodetic data (static offsets) are valuable for determining the distribution of shallower slip but are insensitive to deeper faulting and reveal nothing about the timing of slip. Teleseismic data in the distance range 30 degrees-90 degrees generally involve no modeling difficulties because of simple ray paths and can distinguish shallow from deep slip. Teleseismic data, however, cannot distinguish between different slip scenarios when multiple fault planes are involved because steep takeoff angles lead to ambiguity in timing. Local strong-motion data, on the other hand, are ideal for determining the direction of rupture from directivity but can easily be over modeled with inaccurate Green's functions, leading to misinterpretation of the slip distribution. We show that all three data sets are required to give an accurate description of the Wenchuan rupture. The moment is estimated to be approximately 1.0 x 10(21) N.m with the slip characterized by multiple large patches with slips up to 10 m. Rupture initiates on the southern end of the Pengguan fault and proceeds unilaterally to the northeast. Upon reaching the cross-cutting Xiaoyudong fault, rupture of the adjacent Beichuan fault starts at this juncture and proceeds bilaterally to the northeast and southwest.