活断层的地震响应特征与瞬时地震属性

发布时间：2018-04-30 17:01

本文选题：活动断层 + 二维粘弹性　；参考：《地球科学》2017年03期

【摘要】：活断层探测是断层活动性评判的基础,也是天然地震灾害预防的依据,而浅层地震勘探是活断层探测的有效方法之一;而目前利用浅层地震方法评判断层活动性的能力亟待提高.通过构建了不同宽度破碎带的活断层理论模型,采用二维粘弹性波动方程有限差分法进行了波场响应特征模拟,运用希尔伯特变换方法提取了瞬时频率和相位属性.结果表明:地震水平叠加剖面和瞬时属性相结合可有效获取穿过第四系活断层的响应特征和实现断层活动性评判;当相干噪声达到30%时,水平叠加和瞬时频率属性剖面已难以追踪第四系中弱反射信号,而瞬时相位属性剖面仍可有效追踪;在实际活断层判定中,水平叠加、瞬时频率与瞬时相位地震属性剖面均可判断断层的存在,而穿过第四系的断层(或破碎带)特征瞬时相位属性最为明显和突出,水平叠加剖面次之,瞬时相位地震属性是判定断层活动性的重要和有效的属性.
[Abstract]:Active fault detection is not only the basis of fault activity evaluation, but also the basis of natural earthquake disaster prevention. Shallow seismic exploration is one of the effective methods for active fault detection. At present, the ability to judge fault activity by shallow seismic method needs to be improved. Through constructing the active fault theory model of different width broken zone, the wave field response characteristic was simulated by using the two-dimensional viscoelastic wave equation finite difference method, and the instantaneous frequency and phase attributes were extracted by Hilbert transform method. The results show that the combination of seismic horizontal stacking profile and instantaneous attributes can effectively obtain the response characteristics of the Quaternary active faults and realize the fault activity evaluation, and when the coherent noise reaches 30%, Horizontal stacking and instantaneous frequency attribute profiles are difficult to track weak reflected signals in Quaternary system, but instantaneous phase attribute profiles can still be effectively tracked. The instantaneous frequency and instantaneous phase seismic attribute profiles can be used to judge the existence of faults, while the instantaneous phase attributes of faults (or broken zones) passing through the Quaternary system are the most obvious and prominent, and horizontal stacking profiles are the second. Instantaneous phase seismic attribute is an important and effective attribute in judging fault activity.
【作者单位】：中国地震局地震研究所地震预警湖北省重点实验室;武汉地震工程研究院有限公司;中国地质大学地球物理与空间信息学院;长江科学院水利部岩土力学与工程重点实验室;
【基金】：国家自然科学基金资助项目(No.41202223) 湖北省“十一五”重点建设项目:“湖北省地震背景场探测工程”
【分类号】：P631.4;P315

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