Site Amplification Characteristics at Nankai Seafloor Observation Network, DONET1, Japan, Evaluated Using Spectral Inversion

Research Article| March 27, 2018 Site Amplification Characteristics at Nankai Seafloor Observation Network, DONET1, Japan, Evaluated Using Spectral Inversion Hisahiko Kubo; Hisahiko Kubo aNational Research Institute for Earth Science and Disaster Resilience, 3‐1, Tennodai, Tsukuba, Ibaraki 305‐0006, Japan, hkubo@bosai.go.jp Search for other works by this author on: GSW Google Scholar Takeshi Nakamura; Takeshi Nakamura aNational Research Institute for Earth Science and Disaster Resilience, 3‐1, Tennodai, Tsukuba, Ibaraki 305‐0006, Japan, hkubo@bosai.go.jp Search for other works by this author on: GSW Google Scholar Wataru Suzuki; Wataru Suzuki aNational Research Institute for Earth Science and Disaster Resilience, 3‐1, Tennodai, Tsukuba, Ibaraki 305‐0006, Japan, hkubo@bosai.go.jp Search for other works by this author on: GSW Google Scholar Takeshi Kimura; Takeshi Kimura aNational Research Institute for Earth Science and Disaster Resilience, 3‐1, Tennodai, Tsukuba, Ibaraki 305‐0006, Japan, hkubo@bosai.go.jp Search for other works by this author on: GSW Google Scholar Takashi Kunugi; Takashi Kunugi aNational Research Institute for Earth Science and Disaster Resilience, 3‐1, Tennodai, Tsukuba, Ibaraki 305‐0006, Japan, hkubo@bosai.go.jp Search for other works by this author on: GSW Google Scholar Narumi Takahashi; Narumi Takahashi aNational Research Institute for Earth Science and Disaster Resilience, 3‐1, Tennodai, Tsukuba, Ibaraki 305‐0006, Japan, hkubo@bosai.go.jp Search for other works by this author on: GSW Google Scholar Shin Aoi Shin Aoi aNational Research Institute for Earth Science and Disaster Resilience, 3‐1, Tennodai, Tsukuba, Ibaraki 305‐0006, Japan, hkubo@bosai.go.jp Search for other works by this author on: GSW Google Scholar Author and Article Information Hisahiko Kubo aNational Research Institute for Earth Science and Disaster Resilience, 3‐1, Tennodai, Tsukuba, Ibaraki 305‐0006, Japan, hkubo@bosai.go.jp Takeshi Nakamura aNational Research Institute for Earth Science and Disaster Resilience, 3‐1, Tennodai, Tsukuba, Ibaraki 305‐0006, Japan, hkubo@bosai.go.jp Wataru Suzuki aNational Research Institute for Earth Science and Disaster Resilience, 3‐1, Tennodai, Tsukuba, Ibaraki 305‐0006, Japan, hkubo@bosai.go.jp Takeshi Kimura aNational Research Institute for Earth Science and Disaster Resilience, 3‐1, Tennodai, Tsukuba, Ibaraki 305‐0006, Japan, hkubo@bosai.go.jp Takashi Kunugi aNational Research Institute for Earth Science and Disaster Resilience, 3‐1, Tennodai, Tsukuba, Ibaraki 305‐0006, Japan, hkubo@bosai.go.jp Narumi Takahashi aNational Research Institute for Earth Science and Disaster Resilience, 3‐1, Tennodai, Tsukuba, Ibaraki 305‐0006, Japan, hkubo@bosai.go.jp Shin Aoi aNational Research Institute for Earth Science and Disaster Resilience, 3‐1, Tennodai, Tsukuba, Ibaraki 305‐0006, Japan, hkubo@bosai.go.jp Publisher: Seismological Society of America First Online: 27 Mar 2018 Online Issn: 1943-3573 Print Issn: 0037-1106 © Seismological Society of America Bulletin of the Seismological Society of America (2018) 108 (3A): 1210–1218. https://doi.org/10.1785/0120170254 Article history First Online: 27 Mar 2018 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Hisahiko Kubo, Takeshi Nakamura, Wataru Suzuki, Takeshi Kimura, Takashi Kunugi, Narumi Takahashi, Shin Aoi; Site Amplification Characteristics at Nankai Seafloor Observation Network, DONET1, Japan, Evaluated Using Spectral Inversion. Bulletin of the Seismological Society of America 2018;; 108 (3A): 1210–1218. doi: https://doi.org/10.1785/0120170254 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyBulletin of the Seismological Society of America Search Advanced Search Abstract We investigate the site amplification characteristics in the 0.2–10 Hz frequency band at the DONET1 seafloor observation network, which is installed in the Nankai subduction zone in Japan, using a spectral inversion methodology from observed ground‐motion data. The spectral inversion indicates that the seafloor stations have strong site amplification comparable with or larger than that at land stations in a large basin. The site amplification characteristics significantly differ among the stations, which is likely to reflect the spatial variation in the underground structure beneath DONET1, such as an accretionary wedge and shallow soft sediments. Near‐land stations, which are located above the Kumano trough and the thick accretionary wedge, have a much larger site amplification factor in the broadband frequency range, and their peak values reach ∼20–30⁠. Stations located near the trench axis have a remarkably large site amplification factor at a frequency greater than 2 Hz, with a sharp peak over 30, whereas the low‐frequency (⁠<1 Hz⁠) levels are less than those at other stations. The site amplification characteristics investigated in this study are expected to be useful in evaluating ground motions at seafloor stations and in improving the real‐time forecast of ground motions for subduction earthquakes. 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