Item talk:Q266304

{

 "USGS Publications Warehouse": {
   "@context": "https://schema.org",
   "@type": "CreativeWork",
   "additionalType": "Conference Paper",
   "name": "b values and \u03c9\u2212\u03b3 seismic source models: Implications for tectonic stress variations along active crustal fault zones and the estimation of high-frequency strong ground motion",
   "identifier": [
     {
       "@type": "PropertyValue",
       "propertyID": "USGS Publications Warehouse IndexID",
       "value": "70035508",
       "url": "https://pubs.usgs.gov/publication/70035508"
     },
     {
       "@type": "PropertyValue",
       "propertyID": "USGS Publications Warehouse Internal ID",
       "value": 70035508
     },
     {
       "@type": "PropertyValue",
       "propertyID": "DOI",
       "value": "10.1029/JB084iB05p02235",
       "url": "https://doi.org/10.1029/JB084iB05p02235"
     },
     {
       "@type": "PropertyValue",
       "propertyID": "ISSN",
       "value": "01480227"
     }
   ],
   "inLanguage": "en",
   "datePublished": "1979",
   "dateModified": "2015-06-15",
   "abstract": "In this study the tectonic stress along active crustal fault zones is taken to be of the form\u00a0, where\u00a0\u00a0is the average tectonic stress at depth\u00a0y\u00a0and \u0394\u03c3p(x, y) is a seismologically observable, essentially random function of both fault plane coordinates; the stress differences arising in the course of crustal faulting are derived from \u0394\u03c3p(x, y). Empirically known frequency of occurrence statistics, moment-magnitude relationships, and the constancy of earthquake stress drops may be used to infer that the number of earthquakes\u00a0N\u00a0of dimension \u2265r\u00a0is of the form\u00a0N\u00a0\u223c 1/r2\u00a0and that the spectral composition of \u0394\u03c3p(x, y) is of the form\u00a0, where\u00a0\u00a0is the two-dimensional Fourier transform of \u0394\u03c3p(x, y) expressed in radial wave number\u00a0k. The \u03b3 = 2 model of the far-field shear wave displacement spectrum is consistent with the spectral composition\u00a0, provided that the number of contributions to the spectral representation of the radiated field at frequency \u0192 goes as (k/k0)2, consistent with the quasi-static frequency of occurrence relation\u00a0N\u00a0\u223c 1/r2;k0\u00a0is a reference wave number associated with the reciprocal source dimension. Separately, a variety of seismologic observations suggests that the \u03b3 = 2 model is the one generally, although certainly not always, applicable to the high-frequency spectral decay of the far-field radiation of earthquakes. In this framework, then,\u00a0b\u00a0values near 1, the general validity of the \u03b3 = 2 model, and the constancy of earthquake stress drops independent of size are all related to the average spectral composition of. Should one of these change as a result of premonitory effects leading to failure, as has been specifically proposed for\u00a0b\u00a0values, it seems likely that one or all of the other characteristics will change as well from their normative values. Irrespective of these associations, the far-field, high-frequency shear radiation for the \u03b3 = 2 model in the presence of anelastic attenuation may be interpreted as band-limited, finite duration white noise in acceleration. Its rms value,\u00a0arms, is given by the expression\u00a0arms\u00a0= 0.85[21/2(2\u03c0)2/106] (\u0394\u03c3/\u03c1R)(\u0192max/\u01920)1/2, where \u0394\u03c3 is the earthquake stress drop, \u03c1 is density,\u00a0R\u00a0is hypocentral distance, \u01920\u00a0is the spectral corner frequency, and \u0192max\u00a0is determined by\u00a0R\u00a0and specific attenuation 1/Q. For several reasons, one of which is that it may be estimated in the absence of empirically defined ground motion correlations,\u00a0arms\u00a0holds considerable promise as a measure of high-frequency strong ground motion for engineering purposes.",
   "description": "8 p.",
   "publisher": {
     "@type": "Organization",
     "name": "AGU Publications"
   },
   "author": [
     {
       "@type": "Person",
       "name": "Hanks, Thomas C. thanks@usgs.gov",
       "givenName": "Thomas C.",
       "familyName": "Hanks",
       "email": "thanks@usgs.gov",
       "identifier": {
         "@type": "PropertyValue",
         "propertyID": "ORCID",
         "value": "0000-0003-0928-0056",
         "url": "https://orcid.org/0000-0003-0928-0056"
       },
       "affiliation": [
         {
           "@type": "Organization",
           "name": "Earthquake Science Center",
           "url": "https://www.usgs.gov/centers/earthquake-science-center"
         }
       ]
     }
   ]
 }

}