Source Process of the 2011 Tohoku Earthquake Estimated from the Joint Inversion of Teleseismic Body Waves and Geodetic Data Including Seafloor Observation Data: Source Model with Enhanced Reliability by Using Objectively Determined Inversion Settings
Source Process of the 2011 Tohoku Earthquake Estimated from the Joint Inversion of Teleseismic Body Waves and Geodetic Data Including Seafloor Observation Data: Source Model with Enhanced Reliability by Using Objectively Determined Inversion Settings
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DOI：
10.1785/0120120113
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发表时间：
2013-05-01
影响因子：
3
通讯作者：
Kakehi, Yasumaro
中科院分区：
文献类型：
--
作者：
Kubo, Hisahiko;Kakehi, Yasumaro
利用多时窗分析方法对远震体波和大地测量资料联合反演，估计了2011年东北大地震的破裂过程。为了提高反演解的可靠性，根据客观准则确定了控制时空滑动分布的两个重要反演参数，即每个子断层的最大滑动持续时间（T-sd）和第一时间窗的传播速度（V-ftw）。通过对近源强震波形的小孔径地震阵列数据进行相似分析，确定T-sd为100 s。根据远震和大地滑动模型的匹配，确定V-ftw为2.0 km/s。利用震源区海底地壳形变数据，结合全球定位系统网络数据，显著提高了大地测量反演的空间分辨率。估计地震矩和最大滑移分别为3.4 × 10(22) N.m （m -w = 9.0）和43 m。总破裂时间约为150秒。包括震源在内的断裂面浅部存在较大的滑动，沿沟轴的空间范围约为300 km。该模型与水深测量结果和海啸资料的滑动模型一致。2011年东北地震特征震源模型断层参数之间的关系表明，本次大地震可能出现断层宽度饱和。
The rupture process of the 2011 Tohoku earthquake is estimated from the joint inversion of teleseismic body waves and geodetic data using multiple time-window analysis. To enhance the reliability of the inversion solution, two important inversion-setting parameters that control the spatiotemporal slip distribution, the maximum slip duration of each subfault (T-sd) and the propagation velocity of the first time window (V-ftw), are determined by objective criteria. By performing a semblance analysis of small-aperture seismic array data of near-source strong motion waveforms, T-sd is determined to be 100 s. V-ftw is determined to be 2: 0 km/s from the matching of the teleseismic and geodetic slip models. The spatial resolution of geodetic inversion is significantly improved by using seafloor crustal deformation data in the source area in addition to the terrestrial Global Positioning System network data. The estimated seismic moment and the maximum slip are 3.4 x 10(22) N.m (M-w = 9.0) and 43 m, respectively. The total rupture duration is similar to 150 s. Large slip is seen in the shallow part of the fault surface, including the hypocenter, and its spatial extent along the trench axis is similar to 300 km. This model is consistent with the results of bathymetric surveys and the slip models from tsunami data. The relationships among the fault parameters of the characterized source model of the 2011 Tohoku earthquake suggest the possibility that saturation of fault width occurs for this huge earthquake.