气候变化领域集成服务门户(CCPortal): Seismic Discrimination of Controlled Explosions and Earthquakes Near Mount St. Helens Using P/S Ratios

CCPortal

DOI	10.1029/2020JB020338
	Seismic Discrimination of Controlled Explosions and Earthquakes Near Mount St. Helens Using P/S Ratios
	Wang R.; Schmandt B.; Kiser E.
发表日期	2020
ISSN	21699313
卷号	125 期号:10
英文摘要	Explosions and earthquakes are effectively discriminated by P/S amplitude ratios for moderate magnitude events (M ≥ 4) observed at regional to teleseismic distances (≥200 km). It is less clear if P/S ratios are effective explosion discriminants for lower magnitudes observed at shorter distances. We report new tests of P/S discrimination using a dense seismic array in a continental volcanic arc setting near Mount St. Helens, with 23 single-fired borehole explosions (ML 0.9–2.3) and 406 earthquakes (ML 1–3.3). The array provides up to 95 three-component broadband seismographs, and most source-receiver distances are <120 km. Additional insight is provided by ~3,000 vertical component geophone recordings of each explosion. Potential controls on local distance P/S ratios are investigated, including frequency range, distance, magnitude, source depth, number of seismographs, and site effects. A frequency band of about 10–18 Hz performs better than lower or narrower bands because explosion-induced S wave amplitudes diminish relative to P for higher frequencies. Source depth and magnitude exhibited weak influences on P/S ratios. Site responses for earthquakes and explosions are correlated with each other and with shallow crustal Vp and Vs from traveltime tomography. Overall, the results indicate high potential for local distance P/S explosion discrimination in a continental volcanic arc setting, with ≥98% true positives and ≤6.3% false positives when using the array median from ≥16 stations. Performance is reduced for smaller arrays, especially those with ≤4 stations, thereby emphasizing the importance of array data for discrimination of low magnitude explosions. ©2020. American Geophysical Union. All Rights Reserved.
英文关键词	event classification; explosion monitoring; network optimization; upper crust structure; volcanic earthquakes
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/187583
作者单位	Department of Earth and Planetary Science, University of New Mexico, Albuquerque, NM, United States; Department of Geosciences, University of Arizona, Tucson, AZ, United States
推荐引用方式 GB/T 7714	Wang R.,Schmandt B.,Kiser E.. Seismic Discrimination of Controlled Explosions and Earthquakes Near Mount St. Helens Using P/S Ratios[J],2020,125(10).
APA	Wang R.,Schmandt B.,&Kiser E..(2020).Seismic Discrimination of Controlled Explosions and Earthquakes Near Mount St. Helens Using P/S Ratios.Journal of Geophysical Research: Solid Earth,125(10).
MLA	Wang R.,et al."Seismic Discrimination of Controlled Explosions and Earthquakes Near Mount St. Helens Using P/S Ratios".Journal of Geophysical Research: Solid Earth 125.10(2020).