近震源地震波波形资料反演震源破裂过程的可靠性分析

用近震源波形资料拟合反演地震的震源破裂过程，所包含的一些不确定因素将对反演结果的精度及可靠性产生影响，文中的数值实验分析了所假定的反演断层模型参数的某些不确定性对反演结果的影响程度，并对观测波形的截取长度对反演精度的影响进行了讨论．结果表明：(1)近震源地震波形资料能较好地分辨断层浅部的破裂过程.然而对断层深部的位错分布的约束和反演能力较差．联合使用近、远场地震波资料进行反演，能反演出一个更为完全的整个断层破裂过程的图像.(2)用近震源地震波资料反演时，反演结果对所假定的反演断层的走向和倾角非常敏感.断层走向偏离真实值2°或倾角偏离真实值5°都会导致一个虚假的反演结果.(3)反演中所使用的介质速度结构模型的不确定性，也会对反演结果产生影响.

Analysis on the reliability of the earthquake rupture process inferred from near source waveforms

Several numerical tests have been analyzed in this paper to discuss the influences from the uncertain parameters of the presumed inversion fault model. The influence from the data to the resolution of the inversion results has been also analyzed. We have discussed the influence from the time length of the data and distribution of observational stations. Our research indicates:(1) The near-field waveform data can well reveal the source rupture process of the shallow part of the fault, however, it poorly constrains the slip distribution on the deep part of the fault. Jointly using near- and far-field waveform data can provide more complete message on the rupture process of the whole fault.(2) The near-field inversion result on the source is very sensitive to the strike and dip parameters of the presumed fault model. 2o deviated for the presumed strike and 5o deviated for the presumed dip angle from that of the true fault will lead to a distorted inversion result.(3) The influence from the uncertain media structure for Chi Chi earthquake faulting process inversion might be ignored if we can take the difference between Ma's model and Wu's model as the measure of the media uncertainty.