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Abstract:
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人们常用地震产生的静态库仑应力变化解释地震的空间迁移和余震的空间分布规律,但是,在计算静态库仑应力场时,室内试验数据和观测资料往往无法对计算所涉及的参数进行足够的约束,而参数取值的不确定性会直接影响到静态库仑应力的计算结果。不同研究组得到的汶川地震产生的静态库仑应力变化结果并不一样,为研究不同计算模型和参数的选取对静态库仑应力计算的影响,我们通过建立模型并依次改变参数,分析比较了各个参数对计算结果的影响。结果表明:重力、接收断层位置和走向等的影响较小,其他参数均会对静态库仑应力变化量值和符号造成不同程度的影响,其影响在地震破裂面周边尤其明显,计算时参数敏感性分析不可忽略。
Static Coulomb stress change induced by earthquake slip is used frequently to explain earthquake activities and aftershocks distribution． However，some parameters for the Coulomb stress calculation are unable to be well constrained from laboratory experiments and field observations． Different parameters may directly affect the pattern of static Coulomb stress． The static Coulomb stress changes induced by the Wenchuan earthquake calculated by 6 research groups are not consistent with each other． To investigate how the parameters affect the calculation results，we change the parameters in turn through modeling and compare the results of different calculation parameters． We find that gravity， receiver faults position and strike have little influence on coseismic Coulomb stress change calculation，but other parameters can change the
value and sign of the results in various degrees especially around the earthquake rupture plane． Therefore，the uncertainty of the static Coulomb stress change induced by earthquake should be taken into consideration of the earthquake hazard analysis．
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