{"id":6958,"date":"2025-10-08T18:23:31","date_gmt":"2025-10-08T09:23:31","guid":{"rendered":"https:\/\/www.eri.u-tokyo.ac.jp\/en\/?p=6958"},"modified":"2025-10-08T18:37:34","modified_gmt":"2025-10-08T09:37:34","slug":"t-wave-generation-during-seismic-events-within-submarine-volcanoes","status":"publish","type":"post","link":"https:\/\/www.eri.u-tokyo.ac.jp\/en\/research\/6958\/","title":{"rendered":"T-wave generation during seismic events within submarine volcanoes"},"content":{"rendered":"\n<p class=\"has-text-align-center\">Shunsuke Takemura<\/p>\n\n\n\n<p class=\"has-text-align-center\"><sup>1<\/sup>ERI UTokyo<\/p>\n\n\n\n<p class=\"has-text-align-center\">Takemura, S. Characteristics of\u00a0<em>T<\/em>-wave generation around submarine volcanoes.\u00a0<em>Earth Planets Space<\/em>\u00a0<strong>77<\/strong>, 150 (2025). <a href=\"https:\/\/doi.org\/10.1186\/s40623-025-02284-9\">https:\/\/doi.org\/10.1186\/s40623-025-02284-9<\/a> \u00a0 <\/p>\n\n\n\n<p class=\"has-text-align-left\"><br><br>\u3000Unexpected major tsunamis have occurred at Sumisu Caldera with an interval of about 10 years. Recently, a similar unexpected major tsunami from Sofu Seamount was reported. Sumisu Caldera and Sofu Seamount are submarine volcanoes far south of Japan. Large\u00a0<em>T<\/em>\u00a0waves from the accompanying seismic events were observed during these tsunamigenic events. Characteristics of\u00a0<em>T<\/em>\u00a0waves could be useful as monitoring metrics for seismicity and tsunami excitation at submarine volcanoes. To understand\u00a0<em>T<\/em>-wave generation around submarine volcanoes, I conducted numerical simulations of seismic-acoustic wave propagation from regions around Sumisu Caldera and Sofu Seamount and evaluated\u00a0<em>T<\/em>-wave characteristics at various source locations. For sources just below the seafloor, efficient\u00a0<em>T<\/em>\u00a0waves are generated in wider areas of the simulation regions. As depth below the seafloor increases, epicenters with large-amplitude and short-duration\u00a0<em>T<\/em>\u00a0waves are concentrated within the submarine volcanoes of Sumisu Caldera, Sofu Seamount, and Sofugan Volcano. Exampled seismogram envelopes of <em>T<\/em> waves are illustrated in Figure 1. Large-amplitude and short-duration\u00a0<em>T<\/em>\u00a0waves at a certain seismic station are generated from the seismic source located near the steep (&gt; 10\u00ba) downslopes oriented toward the seismic station. Large-amplitude and short-duration\u00a0<em>T<\/em>\u00a0waves from regions far from steep downslopes oriented toward the seismic station could not be observed at the station. Both slope angle and downslope direction are important for\u00a0<em>T<\/em>-wave generation. The heterogeneous variation of downslopes at submarine volcanoes also causes anisotropic azimuthal patterns of\u00a0<em>T<\/em>\u00a0waves at far stations. The heterogeneities of bathymetric features around source regions cause variability of\u00a0<em>T<\/em>-wave characteristics, and consequently, horizontal and vertical locations of seismic events could be constrained by not only body and\u00a0<em>T<\/em>-wave travel times, but also\u00a0<em>T<\/em>-wave characteristics.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"886\" height=\"543\" src=\"https:\/\/www.eri.u-tokyo.ac.jp\/en\/wp-content\/uploads\/sites\/2\/2025\/10\/image.png\" alt=\"\" class=\"wp-image-6959\" style=\"width:390px;height:auto\" \/><figcaption class=\"wp-element-caption\">Figure 1. <strong>Examples of synthetic vertical-component envelopes at specific epicenters.<\/strong> (a) ep1-3 around Sumisu Caldera and (b) ep4-6 around Sofu Seamount and Sofugan volcano. The dashed lines represent theoretical T-wave traveltimes, assuming a sound velocity of 1.5 km\/s. The hypocenter depths are described by depths below the seafloor (kmbsf: kilometers below the seafloor). The values within brackets in each panel are bathymetric depths from the sea level at each epicenter.<\/figcaption><\/figure>\n","protected":false},"excerpt":{"rendered":"<p>Shunsuke Takemura 1ERI UTokyo Takemura, S. Characteristics of\u00a0T-wave generation around submarine volcanoes.\u00a0Ea &hellip; <a href=\"https:\/\/www.eri.u-tokyo.ac.jp\/en\/research\/6958\/\" class=\"more-link\">Continue reading<span class=\"screen-reader-text\"> &#8220;T-wave generation during seismic events within submarine volcanoes&#8221;<\/span><\/a><\/p>\n","protected":false},"author":9,"featured_media":6959,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[11],"tags":[],"class_list":["post-6958","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\/6958"}],"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=6958"}],"version-history":[{"count":4,"href":"https:\/\/www.eri.u-tokyo.ac.jp\/en\/wp-json\/wp\/v2\/posts\/6958\/revisions"}],"predecessor-version":[{"id":6963,"href":"https:\/\/www.eri.u-tokyo.ac.jp\/en\/wp-json\/wp\/v2\/posts\/6958\/revisions\/6963"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.eri.u-tokyo.ac.jp\/en\/wp-json\/wp\/v2\/media\/6959"}],"wp:attachment":[{"href":"https:\/\/www.eri.u-tokyo.ac.jp\/en\/wp-json\/wp\/v2\/media?parent=6958"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.eri.u-tokyo.ac.jp\/en\/wp-json\/wp\/v2\/categories?post=6958"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.eri.u-tokyo.ac.jp\/en\/wp-json\/wp\/v2\/tags?post=6958"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}