Applicability of Theoretical Horizontal-to-Vertical Ratio of Microtremors Based on the Diffuse Field Concept to Previously Observed Data

• DOI: 10.1785/0120150134
• Publication Date: 2015-10-06T22:29:16Z
• Authors: Hiroshi Kawase; Shinichi Matsushima; Toshimi Satoh; Francisco J. Sánc...
• Keywords: Horizontal and vertical

Abstract Horizontal-to-vertical spectral ratios of microtremors (MHVRs) have been interpreted as representing either the Rayleigh-wave ellipticity or amplitude ratio sum Rayleigh and Love waves in a horizontally layered structure. However, based on recently established diffuse field concept, theoretical form MHVR has proposed to be square root between imaginary part horizontal Green’s function surface that vertical one. The theory assumes energy wavefield inside earth will equipartitioned among various states 3D space. In case microtremors, this may occur for randomly applied point-force loadings after sufficient lapse time allow multiple scattering. Recent works fields suggest equipartition arise several ways, but understanding emergence realistic settings requires further scrutiny. meantime, resulting formula is quite simple, its meaning support from deterministic exact solutions. As references, we use observed microtremor data sites were reported previously validate method (DFM) an alternative explain MHVR. We only with reliable velocity structures compare different methods quantitatively. result, found DFM solutions corresponding 1D well MHVRs most sites. Thus, believe can used invert structure by using tool.