【摘要】 根据美国地质调查局USGS发布的有限断层模型,利用线弹性有限元数值模拟方法,反演了2011年3月11日日本MW9.0级地震在中国华北-东北大陆近地表产生的同震水平位移场及同震应力场;在此基础上,计算了日本大地震引起我国华北-东北大陆内主要活动构造带的静态库仑破裂应力变化,进而探讨其对华北-东北地区地震活动的触发效应。结果表明:(1)日本大地震在华北产生向东的水平位移,由东往西逐渐减小,最大水平位移分布在山东半岛及江苏北部等地,约12mm;在东北产生SE-SEE向的水平位移,最大水平位移分布在吉林东北部,约为30mm;模拟水平位移与GPS观测结果基本相符。(2)日本大地震在我国华北-东北大陆近地表产生的同震应力变化主要是水平的,铅直方向应力变化量为0~0.085kPa,近似为0。两个同震水平主应力中,同震最大水平主应力既有压应力也有张应力,量值为0~0.75kPa,从东北到华北,其方向逐渐由NE→NNE→近SN转为NNW向;同震最小水平主应力为张应力,量值为0~3.20kPa,从东北到华北,其方向逐渐从NW→NWW→近EW转为NEE向;总体上,此次日本地震的同震应力效应虽会对华北-东北大陆现今构造应力场产生一定的影响,但影响程度很弱,并不会改变区域现代构造应力场分布格局。(3)华北-东北大陆内主要活动构造带上的库仑破裂应力变化大部分为正值,但其值均不超过1kPa;其中,郯庐断裂带中、东北段和密山—敦化断裂带中、东北段库仑破裂应力增加值最大,约为0.5~0.8kPa;日本大地震对中国华北-东北地区地震活动起加速触发作用,但程度有限,即便如此,继续并深入研究其引起中国华北-东北大陆主要活动构造带库仑破裂应力变化及地震活动危险性分析,对区域防震减灾工作仍有重要的意义。更多还原

【Abstract】 According to the finite-fault model released by USGS,co-seismic horizontal displacement and horizontal principal stress field in north and northeast China continent generated by Japan MW9.0earthquake on March 11,2011were retrieved by the linear elastic finite element numerical simulation;on this basis,the static Coulomb failure stress of the active fault or tectonic zones in north and northeast China continent were calculated and the trigger effect of the earthquake risk in north and northeast China continent was discussed.The results showed that:(1)the horizontal displacement caused by Japan earthquake in north China continent was eastward and the maximum displacement that distributed in Shandong peninsula and north Jiangsu was about 12mm,while it gradually decreased from east to west;the horizontal displacement in northeast China continent was towards SE-SEE and the maximum displacement that distributed in northeast of Jilin was about30mm;generally the simulation results of the co-seismic horizontal displacement were in agreement with the GPS observations;that(2)near surface co-seismic stress changes generated by Japan MW9.0earthquake were mainly horizontal,while the vertical co-seismic stress change was 0-0.085kPa being approximately equal to zero;between two co-seismic horizontal principal stresses,the maximum co-seismic horizontal principal stress in north and northeast China continent was not only tensile stress but also compressive stress with the value of0-0.75kPa and the direction was converted from NE→NNE→SN to NNW from northeast to north areas;coseismic minimum horizontal principal stress was tensile stress with the magnitude of 0-3.20kPa and orientated from NW→NWW→EW to NEE from northeast to north areas;generally,the co-seismic stress effect could have some effects on the present tectonic stress field in north and northeast continent,however,the distribution pattern of present tectonic stress field did not change;that(3)Coulomb failure stress on the active fracture planes in north and northeast continent mainly increased,however,the increased value was no more than 1kPa,and,in contrast,the increased Coulomb failure stress values of middle and northeast segments of Tan-Lu fault zone as well as Mishan-Dunhua fault zone were the largest.In a word,there were some accelerated triggering actions of the Japan earthquake for the seismic in north and northeast China,however,the triggering intensity was limited.Even so,to carry on further studies is significant for earthquake prevention and disaster mitigation in these areas.更多还原