CAJ | 학술논문

为获得计算复杂地表条件下地震波走时的方法,对常规快速推进法(Fast marching method,简写为FMM)做了两点改进:①引入不等距差分格式,用于地表和界面处的局部走时计算;②增加新的网格节点类型,用于实现不规则边界条件下的窄带技术.通过对算法的计算精度、效率及实例的分析可得,算法计算精度高,其中反射波走时计算的精度高于初至波;不会因为处理不规则边界而引入过多额外的计算量;能灵活稳定地处理各种强起伏复杂地形、近地表及地下复杂介质等问题.计算结果满足复杂地表条件下地震波的传播规律.
위획득계산복잡지표조건하지진파주시적방법,대상규쾌속추진법(Fast marching method,간사위FMM)주료량점개진:①인입불등거차분격식,용우지표화계면처적국부주시계산;②증가신적망격절점류형,용우실현불규칙변계조건하적착대기술.통과대산법적계산정도、효솔급실례적분석가득,산법계산정도고,기중반사파주시계산적정도고우초지파;불회인위처리불규칙변계이인입과다액외적계산량;능령활은정지처리각충강기복복잡지형、근지표급지하복잡개질등문제.계산결과만족복잡지표조건하지진파적전파규률.
Conventional fast marching method (FMM) is improved for traveltime computation. A non-equidistant difference scheme is used to carry local travehime oomputation near surface and interface. New grid node type is used to realize narrow band technique under irregular boundary conditions. Analysis on accuracy, efficiency and numerical tests shows that the new method has high-accuracy and accuracy of the reflection wave is higher than that of the first-arrival wave. The new method does not need too more additional computing eapacity in dealing with irregular boundaries. The new method can treat strong topographical change, near-surface and subsurface complex media effectively and flexibly. The results consist with laws of wave propagation under complex topographical conditions.