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Automatic Determination of Secondary Seismic Phase Arrival Times Using Wavelet Transforms

2003; Seismological Society of America; Volume: 74; Issue: 6 Linguagem: Inglês

10.1785/gssrl.74.6.884

1938-2057

I. M. Tibuleac, E. T. Herrin, Jeanne M. Britton, Robert H. Shumway, A. C. Rosca,

Seismic Waves and Analysis

Other| November 01, 2003 Automatic Determination of Secondary Seismic Phase Arrival Times Using Wavelet Transforms Ileana Madalina Tibuleac; Ileana Madalina Tibuleac 1Weston Geophysical Corporation Search for other works by this author on: GSW Google Scholar Eugene T. Herrin; Eugene T. Herrin 2Southern Methodist University Search for other works by this author on: GSW Google Scholar James M. Britton; James M. Britton 1Weston Geophysical Corporation Search for other works by this author on: GSW Google Scholar Robert Shumway; Robert Shumway 3University of California at Davis Search for other works by this author on: GSW Google Scholar Anca C. Rosca Anca C. Rosca 1Weston Geophysical Corporation Search for other works by this author on: GSW Google Scholar Author and Article Information Ileana Madalina Tibuleac 1Weston Geophysical Corporation Eugene T. Herrin 2Southern Methodist University James M. Britton 1Weston Geophysical Corporation Robert Shumway 3University of California at Davis Anca C. Rosca 1Weston Geophysical Corporation Publisher: Seismological Society of America First Online: 09 Mar 2017 Online Issn: 1938-2057 Print Issn: 0895-0695 © 2003 by the Seismological Society of America Seismological Research Letters (2003) 74 (6): 884–892. https://doi.org/10.1785/gssrl.74.6.884 Article history First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Ileana Madalina Tibuleac, Eugene T. Herrin, James M. Britton, Robert Shumway, Anca C. Rosca; Automatic Determination of Secondary Seismic Phase Arrival Times Using Wavelet Transforms. Seismological Research Letters 2003;; 74 (6): 884–892. doi: https://doi.org/10.1785/gssrl.74.6.884 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietySeismological Research Letters Search Advanced Search Abstract For regional nuclear test monitoring applications, determining accurate locations for small-to-intermediate events (2.5 < mb < 4.0) using sparse stations or arrays is an important and difficult problem. The primary objective of this study was to develop a new and innovative wavelet technique for accurate, reliable, and semiautomatic arrival-time determination, specifically for secondary phases in complex regional seismograms. Since relatively few P-wave observations will be available for hypocenter location, secondary seismic phases, such as Lg and Pg, must be considered to improve location accuracy to the level required for nuclear test monitoring. For these events, single array or single station locations may be used to determine an epicenter for an event, based on estimates of back azimuth and epicentral distance. Because Lg propagates at a consistent group velocity of approximately 3.5±0.2 km/s, the distance estimates using the travel-time difference between this arrival and primary phases (e.g., Pn, Pg) are often quite reliable. However, Lg is a very complicated phase and identifying its onset time on seismograms remains one of the most difficult problems encountered in regional seismology. We have tested an improved version of the Lg wavelet phase-picker (Wavelet 1.0), based on a method developed by Tibuleac and Herrin (1999, 2001), and two other phase-picking methods: CUMSQ (Inclan and Tiao, 1994; Der and Shumway, 1999) and AR (Taylor et al., 1992). We tested the three methods on Lg and Pg (as secondary arrivals) from a data set of 97 shallow (mb < 4.0) well located mine explosions and collocated aftershocks recorded at the TXAR (Lajitas, Texas), NVAR (Mina, Nevada), and PDAR (Pinedale, Wyoming) seismic arrays. Based on a rigorous statistical evaluation, Wavelet 1.0 estimates were more consistent for six out of seven clusters located 300-700 km from three seismic arrays, and produced the lowest location sample standard deviations in the 4.1-5.8 km range, while the other two methods had sample standard deviations well above 5.8 km. The 95% confidence intervals for location standard deviations were estimated as follows: standard deviation between 4.1 and 5.8 km for Wavelet 1.0 picks, between 6.9 and 9.5 km for the analyst picks, and between 5.8 and 8.0 km for CUMSQ picks. Our results show that Wavelet 1.0 offers an improvement in automatic secondary phase-picking over the CUMSQ and AR algorithms and has the potential to be developed into a powerful and robust automatic tool for routine operations. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.