Global and Interregion Characterization of Subduction Interface Earthquakes Derived From Source Time Functions Properties
Global and Interregion Characterization of Subduction Interface Earthquakes Derived From Source Time Functions Properties
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从源时间函数属性推导的俯冲界面地震的全球和区域间特征
DOI：
10.1029/2018jb015932
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
M. Vallée
中科院分区：
文献类型：
--
作者：
A. Chounet;M. Vallée
源时间函数（stf）描述了地震矩率如何随时间释放，并携带了整体破裂特性的信息，如静态应力降和辐射能量。在这项研究中，我们系统地分析了从SCARDEC方法中提取的1433个stf (vallsamade和Douet， 2016, https://doi.org/10.1016/j.pepi.2016.05.012)，其中包含1992年至2014年间发生的Mw≥5.6，浅层（z≤70 km）倾滑机制地震。在全球尺度上，STFs的性质反映了应力降和尺度辐射能量的尺度不变性。第二步，根据地震的构造背景研究这些震源参数：与其他方法一致，我们观察到俯冲界面地震相对于所有其他地震（例如地壳地震）具有更低的应力降和比例辐射能量。最后，通过考虑俯冲带的18个区域段，重点研究了俯冲界面地震（约800次）。我们发现这些片段在宏观破裂性能方面没有相同的特征，这意味着大尺度板块收敛和力学性能影响破裂行为。在给定的段内，应力降或辐射能量的局部非均质性与俯冲带的局部特征有关，特别是我们发现低耦合带产生的地震应力降低，辐射能量成比例。最后一个特征也在更大的尺度上观察到，表明耦合与应力下降之间存在正相关关系。
Source time functions (STFs) describe how the seismic moment rate is released with time, and carry information on integral rupture properties, such as static stress drop and radiated energy. In this study, we systematically analyze a set of 1,433 STFs extracted from the SCARDEC method (Vallée and Douet, 2016, https://doi.org/10.1016/j.pepi.2016.05.012), containing the Mw≥5.6, shallow (z≤70 km) earthquakes with dip‐slip mechanism that occurred between 1992 and 2014. At the global scale, STFs properties indicate scale invariance of stress drop and scaled radiated energy with magnitude. In a second step, these source parameters are investigated in light of the tectonic context of the earthquakes: in agreement with other approaches, we observe that subduction interface earthquakes have lower stress drop and scaled radiated energy relative to all other earthquakes (e.g., crustal earthquakes). Finally, a focus on subduction interface earthquakes (approximately 800 earthquakes) is done by considering 18 regional segments of subduction zones. We find that these segments do not have the same signature in terms of macroscopic rupture properties, which means that large‐scale plate convergence and mechanical properties influence rupture behavior. In a given segment, local heterogeneities of stress drop or radiated energy can be associated with local features of the subduction zone: in particular, we find that low coupled zones generate earthquakes with low stress drop and scaled radiated energy. This last feature, also observed at a larger scale, suggests a positive correlation between coupling and stress drop.