南北地震带区域三维复杂速度模型中地震破裂过程的反演研究

The rupture processes of the M>6 earthquakes occurred in the South-north seismic zone will be studied in this project. The local strong motion data and broadband waveforms recorded from the regional seismographic networks will be inverted for the slip distribution on the finite fault plane. The strong laterally heterogeneous velocity structure beneath the research area is considered in the inversion procedure by taking advantage of the 3D strain Green's functions which are calculated in the previously published tomographic models based on the reciprocity theorem. The reduction of uncertainty and increase of resolution of the inversion results due to the supplement of the local strong motion data and the introduction of the more accurate three-dimensional structure will be quantitatively analyzed. The active faults' behaviors and their possible impacts in the South-north seismic zone could be inferred from the information of these detailed kinematic rupture processes. The way that slip inversion in the three-dimensional velocity model is explored in the project, which also calls for more accurate and finer tomographic models in future.

本项目以发生在南北地震带区域6级以上的地震为研究对象，使用区域地震台网的强震和宽频带波形数据，基于前人研究成果给出的三维复杂速度模型，通过计算三维应变格林函数，对地震破裂过程进行有限断层反演研究。定量分析近场强震数据的增加和三维模型的引入对降低反演结果的不确定性和提高分辨率的效用，并以此为基础探讨南北地震带区域活动断层的行为特征及其可能产生的影响。本项目的实施为未来更多更好的三维速度模型用于地震破裂过程的研究探索了道路，也为三维速度模型的精细化发展提供了驱动。

南北地震带区域地震频发，地下结构复杂，国家烈度速报和预警工程在南北地震带等预警重点区域布设了10000个简易烈度计台站，本项目应用已有的区域三维速度模型和地形起伏数据，收集近场基于MEMS传感器的加速度计的波形数据，在超级计算机上用有限差分方法计算应变格林函数，对区域内M>6地震的破裂过程的进行反演。项目执行中搭建了2008-2021年间中国地震台网1100+个固定地震台站150TB连续波形数据服务平台，它不仅为本项目，还为其他研究项目获取波形数据提供了支持。项目中开发的基于大数据技术的分布式实时数据归档系统从正在建设的地震烈度速报和预警工程的12000+个预警台站获取了大量波形数据用于反演研究。