气候变化领域集成服务门户(CCPortal): Peak Ground Velocity Spatial Variability Revealed by Dense Seismic Array in Southern California

CCPortal

DOI	10.1029/2019JB019157
	Peak Ground Velocity Spatial Variability Revealed by Dense Seismic Array in Southern California
	Johnson C.W.; Kilb D.; Baltay A.; Vernon F.
发表日期	2020
ISSN	21699313
卷号	125 期号:6
英文摘要	Understanding and modeling variability of ground motion is essential for building accurate and precise ground motion prediction equations, which can net site-specific characterization and reduced hazard levels. Here, we explore the spatial variability in peak ground velocity (PGV) at Sage Brush Flats along the San Jacinto Fault in Southern California. We use data from a dense array (0.6 × 0.6 km2, 1,108 geophones, station spacings 10–30 m) deployed in 2014 for ~1 month. These data offer an opportunity to study small-scale variability in this region. We examine 38 earthquakes (2 ≤ ML ≤ 4.2) within 200 km of the array. Fault strands and a small basin impact the ground motions, producing PGV variations up to 22% of the mean and a 40% reduction in P and S wave near-surface velocities. We find along-fault rupture directivity, source, and path effects can increase PGVs by 167%. Surface PGV measurements exceed the colocated borehole station (depth at 148 m) PGV by factors of 3–10, confirming the impact on PGV from near-surface fault structures, basins, topography, and amplifications from soft sediments. Consistently, we find high PGVs within the basin structure. A pair of colocated GaML2.6 events produce repeatable PGV values with similar spatial patterns. The average corner frequencies of these two events are 11–16 Hz, and viable measurements of stress drop can differ by 6.45 MPa. Within this small array, the PGV values are variable implying spatial extrapolation of PGV to regions of known faults and basins, even across a small area, should be done with caution. ©2020. American Geophysical Union. All Rights Reserved.
英文关键词	crustal structure; dense nodal array; ground motions; peak ground velocity; San Jacinto fault zone; stress drop
语种	英语
来源期刊	Journal of Geophysical Research: Solid Earth
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/187804
作者单位	Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, United States; Earthquake Science Center, U.S. Geological Survey, Moffett Field, CA, United States
推荐引用方式 GB/T 7714	Johnson C.W.,Kilb D.,Baltay A.,et al. Peak Ground Velocity Spatial Variability Revealed by Dense Seismic Array in Southern California[J],2020,125(6).
APA	Johnson C.W.,Kilb D.,Baltay A.,&Vernon F..(2020).Peak Ground Velocity Spatial Variability Revealed by Dense Seismic Array in Southern California.Journal of Geophysical Research: Solid Earth,125(6).
MLA	Johnson C.W.,et al."Peak Ground Velocity Spatial Variability Revealed by Dense Seismic Array in Southern California".Journal of Geophysical Research: Solid Earth 125.6(2020).