A Detailed Earthquake Catalog for the San Jacinto Fault‐Zone Region in Southern California
A Detailed Earthquake Catalog for the San Jacinto Fault‐Zone Region in Southern California
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DOI：
10.1029/2019jb017641
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发表时间：
2019-07
期刊：
影响因子：
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通讯作者：
Malcolm C. A. White;Y. Ben‐Zion;F. Vernon
中科院分区：
文献类型：
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作者：
Malcolm C. A. White;Y. Ben‐Zion;F. Vernon
我们开发了一个自动处理程序来得出一个新的地震位置、震级和强度目录，并分析了2008年至2016年圣哈辛托断裂带地区9年的数据。我们的程序使用概率全局搜索位置反演来解释详细的三维速度结构，并使用由互相关波形测量的差异旅行时间来获得高精度的相对事件位置。得到的目录阐明了断裂带的时空地震活动图像，观测到了108,800次地震，震级从−1.8级到5.4级。在与主断层轨迹平行的80公里乘50公里的长方形震源区内，我们估计0.6级及以上地震的检测率为99%，并检测和定位的地震比南加州地震台网目录中的事件多60%左右。结果提供了分析期间重点研究区域现有的最完整的目录，包括区域目录中没有的较深地震和很浅的地震活动斑块。地震活动表现出各种复杂的模式，其中包含有关该地区变形过程的重要信息。具有互相关系数≥0.95的事件对的比例仅为3%左右，表明断裂带中存在不同的活动过程。
We develop an automated processing procedure to derive a new catalog of earthquake locations, magnitudes, and potencies and analyze 9 years of data between 2008 and 2016 in the San Jacinto fault‐zone region. Our procedure accounts for detailed 3‐D velocity structure using a probabilistic global‐search location inversion and obtains high‐precision relative event locations using differential travel times measured by cross‐correlating waveforms. The obtained catalog illuminates spatiotemporal seismicity patterns in the fault zone with observations for 108,800 earthquakes in the magnitude range −1.8 to 5.4. Inside a focus region consisting of an 80‐km by 50‐km rectangle oriented parallel to the main fault trace, we estimate a 99% detection rate of earthquakes with magnitude 0.6 and greater and detect and locate about 60% more events than those present in the Southern California Seismic Network catalog. The results provide the most complete catalog available for the focused study region during the analyzed period and include both deeper events and very shallow patches of seismicity not present in the regional catalog. The seismicity exhibits a variety of complex patterns that contain important information on deformation processes in the region. The fraction of event pairs with waveforms having cross‐correlation coefficients ≥0.95 is only about 3%, indicating diverse processes operating in the fault zone.