Recent seismicity and slab gap beneath Toba caldera (Sumatra) revealed using hypocenter relocation methodology
The Toba Lake is located in the northern part of Sumatra with a large complex caldera that formed by a supervolcano eruption 74,000 years ago and has been influenced by a tectonic process over several centuries. The tectonic process has produced recent seismicity in various systems, one of which is...
| Main Authors: | , , , , |
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| Other Authors: | |
| Format: | Journal Article |
| Language: | English |
| Published: |
2024
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| Subjects: | |
| Online Access: | https://hdl.handle.net/10356/173724 |
| _version_ | 1824456989036511232 |
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| author | Simanjuntak, Andrean Muksin, Umar Asnawi, Yusran Rizal, Syamsul Wei, Shengji |
| author2 | Asian School of the Environment |
| author_facet | Asian School of the Environment Simanjuntak, Andrean Muksin, Umar Asnawi, Yusran Rizal, Syamsul Wei, Shengji |
| author_sort | Simanjuntak, Andrean |
| collection | NTU |
| description | The Toba Lake is located in the northern part of Sumatra with a large complex caldera that formed by a supervolcano eruption 74,000 years ago and has been influenced by a tectonic process over several centuries. The tectonic process has produced recent seismicity in various systems, one of which is the Investigator Fracture Zone (IFZ). The IFZ incorporated with Sumatra subduction as a slab tear in the vertical direction beneath Toba. Therefore, we applied the hypocenter relocation method with a 1-D seismic velocity model to figure out the detailed structure beneath Toba and along the IFZ. The results show a significant change in hypocenter quality which is around 90% of total hypocenters with RMS < 1.0s, while 60% of total hypocenters have RMS < 0.5s following an oblique angle of ~65° beneath Toba. The results strongly highlight a slab gap of Sumatra subduction that may construct a slab tear with a gap at a depth > 100 km, and indicate a shallower dip to the northwest of Toba. A possible slab tear with a slab gap can be found along IFZ as the consequence of a rheologically weak structure which varies from the north to the south. |
| first_indexed | 2025-02-19T04:02:51Z |
| format | Journal Article |
| id | ntu-10356/173724 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2025-02-19T04:02:51Z |
| publishDate | 2024 |
| record_format | dspace |
| spelling | ntu-10356/1737242024-02-26T01:26:00Z Recent seismicity and slab gap beneath Toba caldera (Sumatra) revealed using hypocenter relocation methodology Simanjuntak, Andrean Muksin, Umar Asnawi, Yusran Rizal, Syamsul Wei, Shengji Asian School of the Environment Earth Observatory of Singapore Earth and Environmental Sciences Subduction Slab gap The Toba Lake is located in the northern part of Sumatra with a large complex caldera that formed by a supervolcano eruption 74,000 years ago and has been influenced by a tectonic process over several centuries. The tectonic process has produced recent seismicity in various systems, one of which is the Investigator Fracture Zone (IFZ). The IFZ incorporated with Sumatra subduction as a slab tear in the vertical direction beneath Toba. Therefore, we applied the hypocenter relocation method with a 1-D seismic velocity model to figure out the detailed structure beneath Toba and along the IFZ. The results show a significant change in hypocenter quality which is around 90% of total hypocenters with RMS < 1.0s, while 60% of total hypocenters have RMS < 0.5s following an oblique angle of ~65° beneath Toba. The results strongly highlight a slab gap of Sumatra subduction that may construct a slab tear with a gap at a depth > 100 km, and indicate a shallower dip to the northwest of Toba. A possible slab tear with a slab gap can be found along IFZ as the consequence of a rheologically weak structure which varies from the north to the south. 2024-02-26T01:26:00Z 2024-02-26T01:26:00Z 2022 Journal Article Simanjuntak, A., Muksin, U., Asnawi, Y., Rizal, S. & Wei, S. (2022). Recent seismicity and slab gap beneath Toba caldera (Sumatra) revealed using hypocenter relocation methodology. International Journal of GEOMATE, 23(99), 82-89. https://dx.doi.org/10.21660/2022.99.3623 2186-2982 https://hdl.handle.net/10356/173724 10.21660/2022.99.3623 2-s2.0-85144691256 99 23 82 89 en International Journal of GEOMATE © Int. J. of GEOMATE. All rights reserved, including making copies unless permission is obtained from the copyright proprietors. |
| spellingShingle | Earth and Environmental Sciences Subduction Slab gap Simanjuntak, Andrean Muksin, Umar Asnawi, Yusran Rizal, Syamsul Wei, Shengji Recent seismicity and slab gap beneath Toba caldera (Sumatra) revealed using hypocenter relocation methodology |
| title | Recent seismicity and slab gap beneath Toba caldera (Sumatra) revealed using hypocenter relocation methodology |
| title_full | Recent seismicity and slab gap beneath Toba caldera (Sumatra) revealed using hypocenter relocation methodology |
| title_fullStr | Recent seismicity and slab gap beneath Toba caldera (Sumatra) revealed using hypocenter relocation methodology |
| title_full_unstemmed | Recent seismicity and slab gap beneath Toba caldera (Sumatra) revealed using hypocenter relocation methodology |
| title_short | Recent seismicity and slab gap beneath Toba caldera (Sumatra) revealed using hypocenter relocation methodology |
| title_sort | recent seismicity and slab gap beneath toba caldera sumatra revealed using hypocenter relocation methodology |
| topic | Earth and Environmental Sciences Subduction Slab gap |
| url | https://hdl.handle.net/10356/173724 |
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