{"id":2735,"date":"2020-01-07T10:47:13","date_gmt":"2020-01-07T01:47:13","guid":{"rendered":"http:\/\/www.eri.u-tokyo.ac.jp\/en\/?p=2735"},"modified":"2020-01-07T10:47:15","modified_gmt":"2020-01-07T01:47:15","slug":"migrations-and-clusters-of-shallow-very-low-frequency-earthquakes-in-the-regions-surroundings-stress-accumulation-peaks-along-the-nankai-trough","status":"publish","type":"post","link":"https:\/\/www.eri.u-tokyo.ac.jp\/en\/research\/2735\/","title":{"rendered":"Migrations and Clusters of Shallow Very Low Frequency Earthquakes in the Regions Surroundings Stress Accumulation Peaks along the Nankai Trough"},"content":{"rendered":"\n<p style=\"text-align:center\">S. Takemura<sup>1<\/sup>, A. Noda<sup>2<\/sup>, T. Kubota<sup>2<\/sup>, Y.\nAsano<sup>2<\/sup>, T. Matsuzawa<sup>2<\/sup> and K. Shiomi<sup>2<\/sup> (2019).\nGeophysical Research Letters, 46 (21), 11830-11840, doi:10.1029\/2019GL084666 <\/p>\n\n\n\n<p style=\"text-align:center\"><sup>1<\/sup>ERI Univ. Tokyo, <sup>2<\/sup>NIED<\/p>\n\n\n\n<p>Shallow slow\nearthquakes with rupture speeds between those of regular earthquakes and stable\nsliding often occur in the shallower extents of expected megathrust rupture\nzones. Such shallow slow earthquakes are useful for monitoring the slip\nbehavior of shallow plate boundaries. The spatiotemporal variations of shallow\nslow earthquakes are related to tectonic characteristics including stress\naccumulation, friction properties, and the presence of pore fluids. To\ninvestigate the spatiotemporal variations of shallow slow earthquakes occurring\nalong the Nankai Trough, the activities of shallow very low frequency\nearthquakes (SVLFEs) were examined using template matching and\ncross-correlation relocation analysis. It was found that activity patterns of\nSVLFEs differed in each analyzed segment due to the different structural\ncharacteristics of the shallow Philippine Sea Plate boundary. A detailed\nspatial distribution revealed that SVLFEs tended to cluster or migrate in the\nregions surrounding the boundary stress accumulation peaks on the Philippine\nSea Plate boundary. The obtained results suggest that shallow slow earthquakes\noccur and migrate to release accumulated stress in transitional regions between\nhigh-strength (strongly locked) and low-strength (stable sliding) zones on the shallow\nplate boundary.<\/p>\n\n\n\n<p>The SVLFE detection catalog in this study is available from the GRL website (<a href=\"https:\/\/doi.org\/10.1029\/2019GL084666\">https:\/\/doi.org\/10.1029\/2019GL084666<\/a>) or \u201cSlow Earthquake Database\u201d (<a href=\"http:\/\/www-solid.eps.s.u-tokyo.ac.jp\/~sloweq\/\">http:\/\/www-solid.eps.s.u-tokyo.ac.jp\/~sloweq\/<\/a>).<\/p>\n\n\n\n<figure class=\"wp-block-image\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"491\" src=\"http:\/\/www.eri.u-tokyo.ac.jp\/en\/wp-content\/uploads\/sites\/2\/2020\/01\/eng-1024x491.jpg\" alt=\"\" class=\"wp-image-2736\" srcset=\"https:\/\/www.eri.u-tokyo.ac.jp\/en\/wp-content\/uploads\/sites\/2\/2020\/01\/eng-1024x491.jpg 1024w, https:\/\/www.eri.u-tokyo.ac.jp\/en\/wp-content\/uploads\/sites\/2\/2020\/01\/eng-300x144.jpg 300w, https:\/\/www.eri.u-tokyo.ac.jp\/en\/wp-content\/uploads\/sites\/2\/2020\/01\/eng-768x368.jpg 768w, https:\/\/www.eri.u-tokyo.ac.jp\/en\/wp-content\/uploads\/sites\/2\/2020\/01\/eng-1200x575.jpg 1200w, https:\/\/www.eri.u-tokyo.ac.jp\/en\/wp-content\/uploads\/sites\/2\/2020\/01\/eng-500x240.jpg 500w, https:\/\/www.eri.u-tokyo.ac.jp\/en\/wp-content\/uploads\/sites\/2\/2020\/01\/eng.jpg 1297w\" sizes=\"(max-width: 709px) 85vw, (max-width: 909px) 67vw, (max-width: 1362px) 62vw, 840px\" \/><figcaption>Figure. (a) Spatial distributions of SVLFEs along the Nankai Trough, (b) histogram of the SVLFE counts as a function of shear stress change rate (Noda et al. 2018). The open light blue and blue circles in panels (b) and (d) depict the relocated epicenters of the SVLFEs with CCs greater than 0.45 and 0.60, respectively.<\/figcaption><\/figure>\n\n\n\n<p><\/p>\n","protected":false},"excerpt":{"rendered":"<p>S. Takemura1, A. Noda2, T. Kubota2, Y. Asano2, T. Matsuzawa2 and K. Shiomi2 (2019). Geophysical Research Lette &hellip; <a href=\"https:\/\/www.eri.u-tokyo.ac.jp\/en\/research\/2735\/\" class=\"more-link\">Continue reading<span class=\"screen-reader-text\"> &#8220;Migrations and Clusters of Shallow Very Low Frequency Earthquakes in the Regions Surroundings Stress Accumulation Peaks along the Nankai Trough&#8221;<\/span><\/a><\/p>\n","protected":false},"author":9,"featured_media":2736,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[11],"tags":[],"class_list":["post-2735","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\/2735"}],"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=2735"}],"version-history":[{"count":2,"href":"https:\/\/www.eri.u-tokyo.ac.jp\/en\/wp-json\/wp\/v2\/posts\/2735\/revisions"}],"predecessor-version":[{"id":2738,"href":"https:\/\/www.eri.u-tokyo.ac.jp\/en\/wp-json\/wp\/v2\/posts\/2735\/revisions\/2738"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.eri.u-tokyo.ac.jp\/en\/wp-json\/wp\/v2\/media\/2736"}],"wp:attachment":[{"href":"https:\/\/www.eri.u-tokyo.ac.jp\/en\/wp-json\/wp\/v2\/media?parent=2735"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.eri.u-tokyo.ac.jp\/en\/wp-json\/wp\/v2\/categories?post=2735"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.eri.u-tokyo.ac.jp\/en\/wp-json\/wp\/v2\/tags?post=2735"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}