Regional P-Coda for Stable Estimates of Body Wave Magnitude: Extending the M(s):m(b) Discriminant to Smaller Events

• Main Authors: Mayeda, Kevin, Bonner, Jessie, Hooper, Heather
• Other Authors: WESTON GEOPHYSICAL LEXINGTON MA
• Format: Text
• Language: English
• Published: 2006
• Subjects: Nuclear Explosions and Devices(non-military); *NUCLEAR EXPLOSION TESTING; *SEISMIC WAVES; *ESTIMATES; *DISCRIMINANT ANALYSIS; WAVE PROPAGATION; SURFACE WAVES; SYMPOSIA; METHODOLOGY; SEISMIC CHARACTERIZATION; SEISMIC PROPAGATION; P-CODA METHODOLOGY; COMPONENT REPORTS; PE62601F; WUAFRL1010SMA1; Novaya Zemlya
• Online Access: http://www.dtic.mil/docs/citations/ADA458608; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA458608

The most successful teleseismic discriminant is M(s):m(b), and many studies are underway to try and extend surface wave magnitude (M(s)) estimation to regional distances. A problem that is encountered at regional distances and small magnitudes is how to estimate m(b) so that the M(s):m(b) discriminant is meaningful and consistent with teleseismic measures. Over the past several years, a regional S-coda wave methodology has been developed that provides for the lowest variance estimate of the seismic source spectrum. Thus, regional M(w) and m(b) estimates derived from Sn and Lg coda are very stable, even when only a single station is used. However, these m(b)'s are inherently biased for earthquakes because they are an S-based measurement, and explosions are relatively depleted in S-waves. Previous research projects have used region-specific m(b) scales based on direct measurements of Pn and Pg to improve the M(s):m(b) discrimination, even though the m(b) estimates often had a large variance. The next obvious step to be implemented in the coda wave methodology is the use of P coda for m(b) estimates. This study focuses on developing a regional P-coda methodology to earthquakes and explosions on or near the Nevada, Shagan, Lop Nor, and Novaya Zemlya (NZ) test sites. Presented at the Symposium on Seismic Research (28th), Ground-based Nuclear Explosion Monitoring Technologies, held in Orlando, FL, on 19-21 Sep 2006. Published in the Seismic Research Review, v1 p625-635, 2006. The original document contains color images.