深度震相sSmS特征及其在震源深度确定中的应用

Characteristics of depth phase sSmS and its application in focal depth determination

摘要:

通过一系列理论地震图模拟,研究了莫霍面超临界反射深度震相sSmS的特征,分析了影响该震相的各种因素。结果表明,SmS和sSmS属于高频波,一般情况下在高频段（1Hz左右）可被清晰地观测到;而在更长周期的地震图上,SmS和sSmS的强度比S波或者S多次波弱,不易辨认;地壳结构复杂地区且震源深度较浅时,sSmS震相也不容易被观测到。本文以2011年6月20日腾冲MS5.2地震为研究实例,利用sSmS深度震相确定其震源深度为6km,与其它方法所得结果一致。在利用深度震相测定震源深度的研究中,sSmS震相可以作为震源深度精确测定的手段之一。

Abstract:

We studied the depth phase sSmS and its reference phase SmS dominated by post-critical reflection from Moho using a series of synthetics and analyzed the factors that may affect the phase. The results showed SmS and sSmS were easy to observe in high frequency band （1Hz） , while difficult to identify on long-period seismograms. The complex crustal structure may also make it difficult to identify sSmS phases of events with shallow focal depth. Taken the Tengchong Ms5.2 event on June 20, 2011 as an example, we obtained its focal depth was 6km using depth phase sSmS, which was consistent with the result from the regional waveform modeling, sSmS can be used to determine focal depth with high precision.[著者文摘]