Accession Number : ADA579345


Title :   Determination of Love- and Rayleigh-Wave Magnitudes for Earthquakes and Explosions and Other Studies


Descriptive Note : Final rept. 12 Jun 2009-30 Sep 2012


Corporate Author : WESTON GEOPHYSICAL CORP LEXINGTON MA


Personal Author(s) : Bonner, Jessie L ; Stroujkova, Anastasia ; Anderson, Dale ; McCarthy, Jonathan ; Herrmann, Robert ; Russell, David


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a579345.pdf


Report Date : 30 Dec 2012


Pagination or Media Count : 96


Abstract : Since the 1960s, comparing a Rayleigh-wave magnitude, Ms, to the body-wave magnitude, mb, (e.g., Ms:mb) has been a robust tool for the discrimination of earthquakes and explosions. In this article, we apply a Rayleigh-wave formula as is to Love waves and examine the possibilities for discrimination using only surface wave magnitudes (e.g., Ms:Ms). To calculate the magnitudes we apply the time-domain magnitude technique called Ms(VMAX) developed by Russell (2006) to Rayleigh and Love waves from explosions and earthquakes. Our results indicate that for the majority of the earthquakes studied (75%), the Ms(VMAX) obtained from Love waves is greater than the estimate from Rayleigh waves. Conversely, 79 of 82 nuclear explosions analyzed (96%) had network-averaged Ms(VMAX)-Rayleigh equal to or greater than the Ms(VMAX)-Love. We used logistic regression to examine an Ms(Rayleigh):Ms(Love) discriminant. Cross-validation analysis of the new discriminant correctly identifies 57 of 82 explosions and 246 of 264 earthquakes while misidentifying 22 explosions as earthquakes and 11 earthquakes as explosions. Further comparative research is planned for Ms(Rayleigh):Ms(Love) versus Ms:mb using common data. We fully expect that Ms(Rayleigh):Ms(Love) will contribute significantly to multivariate event identification.


Descriptors :   *LOVE WAVES , *RAYLEIGH WAVES , ATTENUATION , CALIBRATION , EARTHQUAKES , ERRORS , EXCITATION , EXPLOSIONS , MAXIMUM LIKELIHOOD ESTIMATION , SCATTERING , STATISTICS , SURFACE WAVES


Subject Categories : Seismology
      Radiofrequency Wave Propagation


Distribution Statement : APPROVED FOR PUBLIC RELEASE