弹性随机介质模型的特征频率  

The characteristic frequency of the elastic random medium models

作　　者：奚先[1] 姚姚[2] 

机构地区：[1]中国地质大学(武汉)数学与物理系 [2]中国地质大学(武汉)应用地球物理系

出　　处：《地球物理学进展》2005年第3期681-687,共7页Progress in Geophysics

基　　金：国家自然科学基金项目(项目编号:40174034);国家自然科学基金项目(项目编号:40274038)联合资助

摘　　要：为研究弹性随机介质模型中的波场特征,本文使用弹性波动方程正演模拟了平面波在二维弹性随机介质模型中的传播.通过大量正演模拟,我们首先发现若使用不同频率的瑞克子波作为震源函数,计算散射波场的能量相对值ΔE,则对每一个固定的随机介质模型,ΔE都会在某一个与模型对应的震源频率f*处达到最大值.本文由此提出了随机介质模型的特征频率这一新的概念.本文充分说明了特征频率的客观存在性;给出了相应的计算方法;进一步全面研究了随机介质中的各种模型特征(如自相关长度、背景速度、扰动标准差以及模型尺寸等)与模型的特征频率之间的关系;并得到了若干结论和相应的经验关系表达式.In order to study the wave field characteristics in the elastic random medium models, through the simulations of the elastic wave equation, we simulated the propagation of the plane wave in the 2-D elastic random medium models. Via a great deal of forward simulations, we firstly discovered that with each fixed random medium model, if we use Rick wavelet hypocenter functions of different frequencies, and compute the relative energy △E of the scatter wave field, then the △E will achieve maximum value at certain hypocenter frequency f^＊ corresponding to the model. Here from we put forward the new concept of Characteristic Frequency of the random medium models. We have spoken volumes for the objectivity and existence of the Characteristic Frequency; presented the corresponding method of computation; more overall studied the relationships between the random medium＇s different model characteristics （such as autocorrelation length, background velocity, standard deviation of the disturb and the size of the model etc. ） and the random medium＇s Characteristic Frequency; and gained several conclusions and corresponding experiential relation.

关 键 词：随机介质模型 弹性渡模拟 波场特征 特征频率 

分 类 号：P315[天文地球—地震学]