Deep subduction of the Philippine Sea slab and formation of slab window beneath central Japan
Abstract The geometry of the Philippine Sea slab (PHS) subducting beneath the Japanese islands has been imaged to 400 km depth beneath the Kyushu and Chugoku regions, whereas the PHS slab geometry beneath the Hokuriku region has only been determined to ~ 140 km depth, thereby indicating a large east...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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SpringerOpen
2023-05-01
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| Series: | Earth, Planets and Space |
| Subjects: | |
| Online Access: | https://doi.org/10.1186/s40623-023-01846-z |
| _version_ | 1797818144433111040 |
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| author | Kazuki Miyazaki Junichi Nakajima Nobuaki Suenaga Shoichi Yoshioka |
| author_facet | Kazuki Miyazaki Junichi Nakajima Nobuaki Suenaga Shoichi Yoshioka |
| author_sort | Kazuki Miyazaki |
| collection | DOAJ |
| description | Abstract The geometry of the Philippine Sea slab (PHS) subducting beneath the Japanese islands has been imaged to 400 km depth beneath the Kyushu and Chugoku regions, whereas the PHS slab geometry beneath the Hokuriku region has only been determined to ~ 140 km depth, thereby indicating a large east–west asymmetry in the slab subduction. However, geologic evidence suggests that there was symmetrical east–west seafloor spreading along the axis of the Kinan seamount chain when the Shikoku basin was an active spreading center in the PHS plate. This inconsistency suggests that the PHS slab should be present beneath the Hokuriku region. Here we perform P-wave travel-time tomography across central Japan and conduct a two-dimensional plate subduction numerical simulation that reproduces the dual subduction of the PHS and Pacific (PAC) plates to elucidate the PHS slab geometry beneath central Japan. The tomography results reveal a high-velocity anomaly at ~ 150–250 km depth that extends from Wakasa bay to Noto peninsula and a slab window beneath the Hokuriku region. The numerical simulation results suggest that the PHS slab may have torn when it collided with the PAC slab, with the once leading edge of the PHS slab now present along the upper surface of the PAC slab beneath Noto peninsula. These results indicate that the PHS slab exists at ~ 250 km depth beneath the Hokuriku region, although it has been torn owing to its collision with the PAC slab, with this tear propagating westward to form a triangular slab window beneath the Hokuriku region. Graphical Abstract |
| first_indexed | 2024-03-13T09:03:38Z |
| format | Article |
| id | doaj.art-639d4b2cc5104f25822e5c265703997d |
| institution | Directory Open Access Journal |
| issn | 1880-5981 |
| language | English |
| last_indexed | 2024-03-13T09:03:38Z |
| publishDate | 2023-05-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | Earth, Planets and Space |
| spelling | doaj.art-639d4b2cc5104f25822e5c265703997d2023-05-28T11:10:43ZengSpringerOpenEarth, Planets and Space1880-59812023-05-0175111710.1186/s40623-023-01846-zDeep subduction of the Philippine Sea slab and formation of slab window beneath central JapanKazuki Miyazaki0Junichi Nakajima1Nobuaki Suenaga2Shoichi Yoshioka3Department of Earth and Planetary Science, School of Science, Tokyo Institute of TechnologyDepartment of Earth and Planetary Science, School of Science, Tokyo Institute of TechnologyResearch Center for Urban Safety and Security, Kobe UniversityResearch Center for Urban Safety and Security, Kobe UniversityAbstract The geometry of the Philippine Sea slab (PHS) subducting beneath the Japanese islands has been imaged to 400 km depth beneath the Kyushu and Chugoku regions, whereas the PHS slab geometry beneath the Hokuriku region has only been determined to ~ 140 km depth, thereby indicating a large east–west asymmetry in the slab subduction. However, geologic evidence suggests that there was symmetrical east–west seafloor spreading along the axis of the Kinan seamount chain when the Shikoku basin was an active spreading center in the PHS plate. This inconsistency suggests that the PHS slab should be present beneath the Hokuriku region. Here we perform P-wave travel-time tomography across central Japan and conduct a two-dimensional plate subduction numerical simulation that reproduces the dual subduction of the PHS and Pacific (PAC) plates to elucidate the PHS slab geometry beneath central Japan. The tomography results reveal a high-velocity anomaly at ~ 150–250 km depth that extends from Wakasa bay to Noto peninsula and a slab window beneath the Hokuriku region. The numerical simulation results suggest that the PHS slab may have torn when it collided with the PAC slab, with the once leading edge of the PHS slab now present along the upper surface of the PAC slab beneath Noto peninsula. These results indicate that the PHS slab exists at ~ 250 km depth beneath the Hokuriku region, although it has been torn owing to its collision with the PAC slab, with this tear propagating westward to form a triangular slab window beneath the Hokuriku region. Graphical Abstracthttps://doi.org/10.1186/s40623-023-01846-zSeismic tomographyNumerical simulationSlab interaction |
| spellingShingle | Kazuki Miyazaki Junichi Nakajima Nobuaki Suenaga Shoichi Yoshioka Deep subduction of the Philippine Sea slab and formation of slab window beneath central Japan Earth, Planets and Space Seismic tomography Numerical simulation Slab interaction |
| title | Deep subduction of the Philippine Sea slab and formation of slab window beneath central Japan |
| title_full | Deep subduction of the Philippine Sea slab and formation of slab window beneath central Japan |
| title_fullStr | Deep subduction of the Philippine Sea slab and formation of slab window beneath central Japan |
| title_full_unstemmed | Deep subduction of the Philippine Sea slab and formation of slab window beneath central Japan |
| title_short | Deep subduction of the Philippine Sea slab and formation of slab window beneath central Japan |
| title_sort | deep subduction of the philippine sea slab and formation of slab window beneath central japan |
| topic | Seismic tomography Numerical simulation Slab interaction |
| url | https://doi.org/10.1186/s40623-023-01846-z |
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