Evaluation of the southern California seismic velocity models through simulation of recorded events
Evaluation of the southern California seismic velocity models through simulation of recorded events
复制标题
通过模拟记录事件评估南加州地震速度模型
DOI：
10.1093/gji/ggw085
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发表时间：
2016
影响因子：
2.8
通讯作者：
Keli Cheng
中科院分区：
文献类型：
--
作者：
R. Taborda;Shima Azizzadeh;N. Khoshnevis;Keli Cheng
在过去的二十年里，人们投入了大量的精力来开发美国南加州地区的各种地震速度模型。这些模型主要用于正向波传播模拟研究，但也作为层析成像和震源反演的基础模型。其中两个模型，群落速度模型CVM-S和CVM-H，是该地区最常用的模型。这包括原始模型的两种可选变体，最近发布的CVM-S4.26将层射反演结果整合到CVM-S中，以及用户控制的CVM-H选项，用基于avs30的岩土模型取代近地表剖面。尽管这两种模型都被建模界认为是可以接受的，但众所周知，它们对该地区地壳结构和沉积沉积的表达存在差异，从而导致正反演问题的结果不同。在本文中，我们通过对近期事件的一系列模拟的评估，评估了这些模型用于预测大洛杉矶地区地面运动的准确性。我们总共考虑了1998年至2014年间的30次中震级地震（3.5 <Mw< 5.5），并将合成数据与地震台网记录的数据进行了比较。模拟采用有限元并行程序进行，数值模型满足最大频率为1 Hz，最小横波速度为200 m s - 1。数据和合成物之间的比较通过拟合优度（GOF）标准进行定量排序。我们分析了所有事件和所有模型的GOF结果的区域分布，并从结果中得出结论，以及这些结果如何与模型相关。我们发现，根据我们的比较，CVM-S4.26模型始终产生更好的结果。
Significant effort has been devoted over the last two decades to the development of various seismic velocity models for the region of southern California, United States. These models are mostly used in forward wave propagation simulation studies, but also as base models for tomographic and source inversions. Two of these models, the community velocity models CVM-S and CVM-H, are among the most commonly used for this region. This includes two alternative variations to the original models, the recently released CVM-S4.26 which incorporates results from a sequence of tomographic inversions into CVM-S, and the user-controlled option of CVM-H to replace the near-surface profiles with aVS30-based geotechnical model. Although either one of these models is regarded as acceptable by the modeling community, it is known that they have differences in their representation of the crustal structure and sedimentary deposits in the region, and thus can lead to different results in forward and inverse problems. In this paper, we evaluate the accuracy of these models when used to predict the ground motion in the greater Los Angeles region by means of an assessment of a collection of simulations of recent events. In total, we consider 30 moderate-magnitude earthquakes (3.5 <Mw< 5.5) between 1998 and 2014, and compare synthetics with data recorded by seismic networks during these events. The simulations are done using a finite-element parallel code, with numerical models that satisfy a maximum frequency of 1 Hz and a minimum shear wave velocity of 200 m s−1. The comparisons between data and synthetics are ranked quantitatively by means of a goodness-of-fit (GOF) criteria. We analyse the regional distribution of the GOF results for all events and all models, and draw conclusions from the results and how these correlate to the models. We find that, in light of our comparisons, the model CVM-S4.26 consistently yields better results.