{"id":2853,"date":"2020-06-10T10:20:56","date_gmt":"2020-06-10T01:20:56","guid":{"rendered":"http:\/\/www.eri.u-tokyo.ac.jp\/en\/?p=2853"},"modified":"2020-06-10T10:20:58","modified_gmt":"2020-06-10T01:20:58","slug":"centroid-moment-tensor-inversions-of-offshore-earthquakes-using-a-three-dimensional-velocity-structure-model-slip-distributions-on-the-plate-boundary-along-the-nankai-trough","status":"publish","type":"post","link":"https:\/\/www.eri.u-tokyo.ac.jp\/en\/research\/2853\/","title":{"rendered":"Centroid moment tensor inversions of offshore earthquakes using a three-dimensional velocity structure model: slip distributions on the plate boundary along the Nankai Trough"},"content":{"rendered":"\n<p style=\"text-align:center\">S. Takemura<sup>1<\/sup>, R. Okuwaki<sup>2<\/sup>, T. Kubota<sup>3<\/sup>, K.\nShiomi<sup>3<\/sup>, T. Kimura<sup>3<\/sup> and A. Noda<sup>3<\/sup> (2020).\nGeophysical Journal International, 222 (2), 1109-1121, doi:10.1093\/gji\/ggaa238<\/p>\n\n\n\n<p style=\"text-align:center\"><sup>1<\/sup>ERI Univ. Tokyo, <sup>2<\/sup>Univ. Tsukuba, <sup>3<\/sup>NIED<\/p>\n\n\n\n<p>Due to\ncomplex 3-D heterogeneous structures, conventional 1-D analysis techniques\nusing onshore seismograms can yield incorrect estimation of earthquake source\nparameters, especially dip angles and centroid depths of offshore earthquakes.\nCombining long-term onshore seismic observations and numerical simulations of\nseismic wave propagation in a 3-D model, we conducted centroid moment tensor\n(CMT) inversions of earthquakes along the Nankai Trough between April 2004 and\nAugust 2019 to evaluate decade-scale seismicity. Green&#8217;s functions for CMT\ninversions of earthquakes with moment magnitudes of 4.3\u20136.5 were evaluated\nusing finite-difference method simulations of seismic wave propagation in the\nregional 3-D velocity structure model. Significant differences of focal\nmechanisms and centroid depths between previous 1-D and our 3-D catalogues were\nfound in the solutions of offshore earthquakes. By introducing the 3-D\nstructures of the low-velocity accretionary prism and the Philippine Sea Plate,\ndip angles and centroid depths for offshore earthquakes were well-constrained.\nTeleseismic CMT also provides robust solutions, but our regional 3-D CMT could\nprovide better constraints of dip angles. Our 3-D CMT catalogue and published\nslow earthquake catalogues depicted spatial distributions of slip behaviours on\nthe plate boundary along the Nankai Trough. The regular and slow interplate\nearthquakes were separately distributed, with these distributions reflecting\nthe heterogeneous distribution of effective strengths along the Nankai Trough\nplate boundary. By comparing the spatial distribution of seismic slip on the\nplate boundary with the slip-deficit rate distribution, regions with strong\ncoupling were clearly identified.<\/p>\n\n\n\n<p>The CMT catalog in this study is\navailable from <a href=\"https:\/\/doi.org\/10.5281\/zenodo.3674161\">https:\/\/doi.org\/10.5281\/zenodo.3674161<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>S. Takemura1, R. Okuwaki2, T. Kubota3, K. Shiomi3, T. Kimura3 and A. Noda3 (2020). Geophysical Journal Interna &hellip; <a href=\"https:\/\/www.eri.u-tokyo.ac.jp\/en\/research\/2853\/\" class=\"more-link\">Continue reading<span class=\"screen-reader-text\"> &#8220;Centroid moment tensor inversions of offshore earthquakes using a three-dimensional velocity structure model: slip distributions on the plate boundary along the Nankai Trough&#8221;<\/span><\/a><\/p>\n","protected":false},"author":9,"featured_media":2854,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[11],"tags":[],"class_list":["post-2853","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\/2853"}],"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=2853"}],"version-history":[{"count":1,"href":"https:\/\/www.eri.u-tokyo.ac.jp\/en\/wp-json\/wp\/v2\/posts\/2853\/revisions"}],"predecessor-version":[{"id":2855,"href":"https:\/\/www.eri.u-tokyo.ac.jp\/en\/wp-json\/wp\/v2\/posts\/2853\/revisions\/2855"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.eri.u-tokyo.ac.jp\/en\/wp-json\/wp\/v2\/media\/2854"}],"wp:attachment":[{"href":"https:\/\/www.eri.u-tokyo.ac.jp\/en\/wp-json\/wp\/v2\/media?parent=2853"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.eri.u-tokyo.ac.jp\/en\/wp-json\/wp\/v2\/categories?post=2853"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.eri.u-tokyo.ac.jp\/en\/wp-json\/wp\/v2\/tags?post=2853"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}