隐伏活断层地震勘探正演模拟方法

浅层高分辨率地震勘探是城市活断层探测手段中最有效、最可靠的方法之一，但是由于隐伏活断层勘探时存在着勘探深度浅、地层的属性差异小以及环境噪声大等因素，导致地震勘探数据信噪比低、反射信号弱等问题，严重影响地震数据的采集、处理和解释。采用一阶应力-速度方程的高阶交错网格有限差分方法, 结合完全匹配层(PML)的边界处理方法和通量校正(FCT)法消除频散的技术手段，对活断层模型地震勘探进行正演模拟，清晰直观地表现了断层处的细微差别，有助于地震勘探中对信号的分析与理解。结果表明，这些处理手段结合波动方程有限差分算法，能够有效实现薄层、弱反射的隐伏活断层模型的波场正演模拟，可有效识别隐伏活断层的断层倾角、断距、规模、跨越范围、断层深度以及断裂带影响范围，为分析这些参数对地震记录的影响提供有力帮助，同时结合实测地震数据的处理、解释，为防灾减灾提供具体有力的判据。

Seismic Modeling Method for Shallow Seismic Exploration of Buried Active Fault

The shallow high-resolution seismic prospecting is one of the effective and reliable methods in urban active fault detection. For the shallowness of the object stratum, the tiny difference between the seismic attribute of strata and the ambient noise, it is hard to process and interpret seismic data. In this paper, the staggered-grid high-order difference method of one-order elastic wave equations, which are expressed with velocity and stress applying the flux-corrected transport(FCT) method with a perfectly matched layer (PML) absorbing boundary condition, are used to obtain the synthetic common-shot profile for shallow fault model. The simulated results of fault model show that this method is accurate and distinct. This seismic modeling method is helpful for approximately estimating the location, the depth and the scope of the fault from the synthetic profile during survey, and improving the efficiency of seismic prospecting and the precision and resolution of seismic data processing and interpretation.