Print Email Facebook Twitter The potential of imaging subsurface heterogeneities by local, natural earthquakes Title The potential of imaging subsurface heterogeneities by local, natural earthquakes Author Nishitsuji, Y. Doi, I. Draganov, D.S. Faculty Civil Engineering and Geosciences Department Geoscience & Engineering Date 2014-10-23 Abstract We have developed a new imaging technique of subsurface heterogeneities that uses Sp-waves from natural earthquakes. This technique can be used as a first screening tool in frontier exploration areas before conventional active exploration. Analyzing Sp-waves from 28 earthquakes (Mj 2.0 to 4.2) recorded by two permanent seismic stations, we built an image of the distributions of velocity discontinuities in southeastern offshore Hokkaido, Japan, where intraplate earthquakes in the Pacific plate frequently occur. Our results indicated the presence of three horizontally continuous, distinct discontinuities corresponding to geologic boundaries estimated in a previous study.We also derived the frequency-dependent quality factor Q for P- and S-waves and use it as a method of characterizing physical properties of subsurface structure. The waveform traces with coherent Sp-phases in the southern part of the study area generally show a constant QS?QP ratio, and the waveform traces with randomly distributed phases in the northern part show a large variation of the QS?QP ratio (including several high values). Subject converted wavecrustal structureearthquakepassive seismic To reference this document use: http://resolver.tudelft.nl/uuid:4064f85f-968b-47f7-95fc-25414319514e DOI https://doi.org/10.1190/GEO2013-0391.1 ISSN 0016-8033 Source Geophysics, 72 (6), 2014 Part of collection Institutional Repository Document type journal article Rights © 2014 Society of Exploration Geophysicists Files PDF 309486.pdf 1.1 MB Close viewer /islandora/object/uuid:4064f85f-968b-47f7-95fc-25414319514e/datastream/OBJ/view