{"id":953,"date":"2016-08-29T10:27:45","date_gmt":"2016-08-29T01:27:45","guid":{"rendered":"http:\/\/www.eri.u-tokyo.ac.jp\/en\/?p=953"},"modified":"2016-08-29T10:34:42","modified_gmt":"2016-08-29T01:34:42","slug":"geometric-effect-on-a-laboratory-scale-wavefield-inferred-from-a-three-dimensional-numerical-simulation","status":"publish","type":"post","link":"https:\/\/www.eri.u-tokyo.ac.jp\/en\/research\/953\/","title":{"rendered":"Geometric effect on a laboratory-scale wavefield inferred from a three-dimensional numerical simulation"},"content":{"rendered":"<p style=\"text-align: center\">Nana Yoshimitsu<sub> a,b<\/sub>,\u204e, Takashi Furumura<sub> a<\/sub>, Takuto Maeda <sub>a<\/sub><br \/>\n<sub>a<\/sub> Earthquake Research Institute, The University of Tokyo, Tokyo, Japan<br \/>\n<sub>b<\/sub> Department of Geophysics, Stanford University, California, USA<\/p>\n<p style=\"text-align: center\">Journal of Applied Geophysics 132 (2016) 184\u2013192,<br \/>\nhttp:\/\/dx.doi.org\/10.1016\/j.jappgeo.2016.07.002<\/p>\n<p style=\"text-align: left\"><strong>Abstract<\/strong><\/p>\n<p style=\"text-align: left\">The coda part of a waveform transmitted through a laboratory sample should be examined for the highresolution\u00a0monitoring of the sample characteristics in detail. However, the origin and propagation process of\u00a0the later phases in a finite-sized small sample are very complicated with the overlap of multiple unknown reflections\u00a0and conversions. In this study, we investigated the three-dimensional (3D) geometric effect of a finite-sized\u00a0cylindrical sample to understand the development of these later phases. This study used 3D finite difference\u00a0method simulation employing a free-surface boundary condition over a curved model surface and a realistic circular\u00a0shape of the source model. The simulated waveforms and the visualized 3D wavefield in a stainless steel\u00a0sample clearly demonstrated the process of multiple reflections and the conversions of the P and S waves at\u00a0the side surface as well as at the top and bottom of the sample. Rayleigh wave propagation along the curved\u00a0side boundary was also confirmed, and these waves dominate in the later portion of the simulated waveform\u00a0with much larger amplitudes than the P and S wave reflections. The feature of the simulated waveforms showed\u00a0good agreement with laboratory observed waveforms. For the simulation, an introduction of an absorbing\u00a0boundary condition at the top and bottom of the samplemade it possible to efficiently separate the contribution\u00a0of the vertical and horizontal boundary effects in the simulated wavefield. This procedure helped to confirm the\u00a0additional finding of vertically propagating multiple surface waves and their conversion at the corner of the\u00a0sample. This new laboratory-scale 3D simulation enabled the appearance of a variety of geometric effects that\u00a0constitute the later phases of the transmitted waves.<\/p>\n<p style=\"text-align: left\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-954 size-medium\" src=\"http:\/\/www.eri.u-tokyo.ac.jp\/en\/wp-content\/uploads\/sites\/2\/2016\/08\/Figure1_NY2016-300x159.jpg\" alt=\"Figure1_NY2016\" width=\"300\" height=\"159\" srcset=\"https:\/\/www.eri.u-tokyo.ac.jp\/en\/wp-content\/uploads\/sites\/2\/2016\/08\/Figure1_NY2016-300x159.jpg 300w, https:\/\/www.eri.u-tokyo.ac.jp\/en\/wp-content\/uploads\/sites\/2\/2016\/08\/Figure1_NY2016-768x408.jpg 768w, https:\/\/www.eri.u-tokyo.ac.jp\/en\/wp-content\/uploads\/sites\/2\/2016\/08\/Figure1_NY2016-1024x544.jpg 1024w, https:\/\/www.eri.u-tokyo.ac.jp\/en\/wp-content\/uploads\/sites\/2\/2016\/08\/Figure1_NY2016-1200x637.jpg 1200w, https:\/\/www.eri.u-tokyo.ac.jp\/en\/wp-content\/uploads\/sites\/2\/2016\/08\/Figure1_NY2016.jpg 1573w\" sizes=\"(max-width: 300px) 85vw, 300px\" \/><\/p>\n<p style=\"text-align: left\">\n","protected":false},"excerpt":{"rendered":"<p>Nana Yoshimitsu a,b,\u204e, Takashi Furumura a, Takuto Maeda a a Earthquake Research Institute, The University of T &hellip; <a href=\"https:\/\/www.eri.u-tokyo.ac.jp\/en\/research\/953\/\" class=\"more-link\">Continue reading<span class=\"screen-reader-text\"> &#8220;Geometric effect on a laboratory-scale wavefield inferred from a three-dimensional numerical simulation&#8221;<\/span><\/a><\/p>\n","protected":false},"author":9,"featured_media":954,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[11],"tags":[],"class_list":["post-953","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-research"],"_links":{"self":[{"href":"https:\/\/www.eri.u-tokyo.ac.jp\/en\/wp-json\/wp\/v2\/posts\/953"}],"collection":[{"href":"https:\/\/www.eri.u-tokyo.ac.jp\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.eri.u-tokyo.ac.jp\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.eri.u-tokyo.ac.jp\/en\/wp-json\/wp\/v2\/users\/9"}],"replies":[{"embeddable":true,"href":"https:\/\/www.eri.u-tokyo.ac.jp\/en\/wp-json\/wp\/v2\/comments?post=953"}],"version-history":[{"count":6,"href":"https:\/\/www.eri.u-tokyo.ac.jp\/en\/wp-json\/wp\/v2\/posts\/953\/revisions"}],"predecessor-version":[{"id":961,"href":"https:\/\/www.eri.u-tokyo.ac.jp\/en\/wp-json\/wp\/v2\/posts\/953\/revisions\/961"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.eri.u-tokyo.ac.jp\/en\/wp-json\/wp\/v2\/media\/954"}],"wp:attachment":[{"href":"https:\/\/www.eri.u-tokyo.ac.jp\/en\/wp-json\/wp\/v2\/media?parent=953"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.eri.u-tokyo.ac.jp\/en\/wp-json\/wp\/v2\/categories?post=953"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.eri.u-tokyo.ac.jp\/en\/wp-json\/wp\/v2\/tags?post=953"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}