日本Mw 9.0地震的重力和GPS研究及其对中国华北区域的影响

Earthquake rupture process and re-pregnancy provide an opportunity for investigation on the viscoelastic properties of the Earth and fault slip. Based on surface gravity observation data obtained from "Sino-Japanese Cooperation Project on the 2011 Northeastern Japan Earthquake (Mw 9.0)," combining with GPS, GRACE, such as multi-source observation data , and uniforming interpretation , joint inversing the viscoelastic Earth structure of the hazard region and the fault slip distribution. Using viscoelastic dislocation theory (Tanaka, 2006) to simulate co- and post-seismic gravity and displacement changes and comparing with real observations data and research the physical reasons for the co- and post-seismic gravity change; Optimizing co-seismic fault slip model by taking into account the weight of gravity observation data constrained with least square method; Using Bayesian inversion theory to inverse distribution of fault afterslip with gravity and GPS observational data; Discriminating and quantitative analyzing the effect and their range of viscoelastic relaxation and fault afterslip on the gravitational and deformation field;Furthermore, comparing the rates of crustal deformation field in the Northeast region of China and Japan. Studying the effect of Japan Tohoku earthquake on the crustal deformation in North China. This study has important scientific value and reference significance on investigating the geodynamic characters and earthquake prediction for China northern and Japan Tohoku regions.

地震破裂过程与再孕育为断层滑动与地球的粘弹特性研究提供了契机。本项目基于“中日合作”的2011年日本东北地震(Mw 9.0)地表混合重力观测数据，融合GPS、GRACE等多源数据、统一解释、联合反演地震断层滑动和震中区域的地球粘弹结构。利用粘弹位错理论模拟地震的同震和震后的重力与位移并比对观测结果，探讨同震及震后重力变化的物理原因；使用考虑权重的重力数据约束的最小二乘法优化同震断层滑动模型；利用贝叶斯理论融合重力、GPS等观测数据反演断层余滑分布；区分并定量分析粘弹弛豫与断层余滑对重力场及形变场的影响及范围；研究日本东北地震对中国华北区域地壳形变态势的影响；该研究对于探讨中国华北、日本东北区域的地球动力学特征和地震预报具有重要的科学价值和参考意义。

地震破裂过程与再孕育为断层滑动与地球的粘弹特性研究提供了契机。本项目基于“中日合作”的2011年日本东北地震(Mw 9.0)地表混合重力观测数据，融合GPS、GRACE等多源数据、统一解释、联合反演地震断层滑动和震中区域的地球粘弹结构。利用粘弹位错理论模拟地震的同震和震后的重力与位移并比对观测结果，探讨同震及震后重力变化的物理原因；使用考虑权重的重力数据约束的最小二乘法优化同震断层滑动模型；利用贝叶斯理论融合重力、GPS等观测数据反演断层余滑分布；区分并定量分析粘弹弛豫与断层余滑对重力场及形变场的影响及范围；研究日本东北地震对中国华北区域地壳形变态势的影响；该研究对于探讨中国华北、日本东北区域的地球动力学特征和地震预报具有重要的科学价值和参考意义。.本项目主要完成了以下研究内容：（1）结合同震的重力与GPS数据分析了同震重力变化的物理原因；（2）模拟了同震及震后的重力、位移及大地水准面的变化；（3）优化了同震断层模型。（4）主震及震级大于7.0的前震和余震对日本东北和中国东北区域的影响研究，该内容还在进一步完善处理中。