Seismic background level (SBL) growth can reveal slowly developing long-term eruption precursors
Abstract The accelerating growth of seismic unrest before eruptions has been observed at many volcanoes and utilized for eruption forecasts. However, there are still many eruptions for which no precursory unrest has been identified, even at well-monitored volcanoes. The recent eruptions of Shinmoe-d...
| Main Authors: | , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Nature Portfolio
2023-04-01
|
| Series: | Scientific Reports |
| Online Access: | https://doi.org/10.1038/s41598-023-32875-z |
| _version_ | 1827966310426869760 |
|---|---|
| author | Mie Ichihara Takao Ohminato Kostas I. Konstantinou Kazuya Yamakawa Atsushi Watanabe Minoru Takeo |
| author_facet | Mie Ichihara Takao Ohminato Kostas I. Konstantinou Kazuya Yamakawa Atsushi Watanabe Minoru Takeo |
| author_sort | Mie Ichihara |
| collection | DOAJ |
| description | Abstract The accelerating growth of seismic unrest before eruptions has been observed at many volcanoes and utilized for eruption forecasts. However, there are still many eruptions for which no precursory unrest has been identified, even at well-monitored volcanoes. The recent eruptions of Shinmoe-dake, Japan, have been another negative example of this kind. Here we present seismological evidence that the eruption preparation had been ongoing at the shallow depths beneath Shinmoe-dake for several months to a year. We investigated the seismic background level (SBL) of eleven-year data recorded around the volcano, including two stations about 1 km from the eruptive crater. We searched for persistent weak signals, focusing on low-amplitude time windows recorded during quiet nighttime. Then the spectra of daily background noise were classified by clustering analysis. The SBL analysis successfully revealed very weak precursory tremors from more than several months before the eruption, and residual tremors to the end of the eruptive period. The precursory signals grew acceleratory in a similar way as is assumed in the material failure forecast method applied to eruption forecasts. However, their growth was significantly slower and longer compared to other cases reported in the literature. Such slow and quiet eruption preparations would not be captured by conventional seismological methods. We expect that long-term SBL analyses on proximal seismic data will help detect early precursors, even at seismically quiet volcanoes, and will also help towards judging the end of an eruptive period. |
| first_indexed | 2024-04-09T17:46:52Z |
| format | Article |
| id | doaj.art-27610a1bdc054f558dfaaee6115a1840 |
| institution | Directory Open Access Journal |
| issn | 2045-2322 |
| language | English |
| last_indexed | 2024-04-09T17:46:52Z |
| publishDate | 2023-04-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | Scientific Reports |
| spelling | doaj.art-27610a1bdc054f558dfaaee6115a18402023-04-16T11:14:35ZengNature PortfolioScientific Reports2045-23222023-04-0113111010.1038/s41598-023-32875-zSeismic background level (SBL) growth can reveal slowly developing long-term eruption precursorsMie Ichihara0Takao Ohminato1Kostas I. Konstantinou2Kazuya Yamakawa3Atsushi Watanabe4Minoru Takeo5Earthquake Research Institute, University of TokyoEarthquake Research Institute, University of TokyoDepartment of Earth Sciences, National Central UniversityMount Fuji Research Institute Yamanashi Prefectural GovernmentEarthquake Research Institute, University of TokyoEarthquake Research Institute, University of TokyoAbstract The accelerating growth of seismic unrest before eruptions has been observed at many volcanoes and utilized for eruption forecasts. However, there are still many eruptions for which no precursory unrest has been identified, even at well-monitored volcanoes. The recent eruptions of Shinmoe-dake, Japan, have been another negative example of this kind. Here we present seismological evidence that the eruption preparation had been ongoing at the shallow depths beneath Shinmoe-dake for several months to a year. We investigated the seismic background level (SBL) of eleven-year data recorded around the volcano, including two stations about 1 km from the eruptive crater. We searched for persistent weak signals, focusing on low-amplitude time windows recorded during quiet nighttime. Then the spectra of daily background noise were classified by clustering analysis. The SBL analysis successfully revealed very weak precursory tremors from more than several months before the eruption, and residual tremors to the end of the eruptive period. The precursory signals grew acceleratory in a similar way as is assumed in the material failure forecast method applied to eruption forecasts. However, their growth was significantly slower and longer compared to other cases reported in the literature. Such slow and quiet eruption preparations would not be captured by conventional seismological methods. We expect that long-term SBL analyses on proximal seismic data will help detect early precursors, even at seismically quiet volcanoes, and will also help towards judging the end of an eruptive period.https://doi.org/10.1038/s41598-023-32875-z |
| spellingShingle | Mie Ichihara Takao Ohminato Kostas I. Konstantinou Kazuya Yamakawa Atsushi Watanabe Minoru Takeo Seismic background level (SBL) growth can reveal slowly developing long-term eruption precursors Scientific Reports |
| title | Seismic background level (SBL) growth can reveal slowly developing long-term eruption precursors |
| title_full | Seismic background level (SBL) growth can reveal slowly developing long-term eruption precursors |
| title_fullStr | Seismic background level (SBL) growth can reveal slowly developing long-term eruption precursors |
| title_full_unstemmed | Seismic background level (SBL) growth can reveal slowly developing long-term eruption precursors |
| title_short | Seismic background level (SBL) growth can reveal slowly developing long-term eruption precursors |
| title_sort | seismic background level sbl growth can reveal slowly developing long term eruption precursors |
| url | https://doi.org/10.1038/s41598-023-32875-z |
| work_keys_str_mv | AT mieichihara seismicbackgroundlevelsblgrowthcanrevealslowlydevelopinglongtermeruptionprecursors AT takaoohminato seismicbackgroundlevelsblgrowthcanrevealslowlydevelopinglongtermeruptionprecursors AT kostasikonstantinou seismicbackgroundlevelsblgrowthcanrevealslowlydevelopinglongtermeruptionprecursors AT kazuyayamakawa seismicbackgroundlevelsblgrowthcanrevealslowlydevelopinglongtermeruptionprecursors AT atsushiwatanabe seismicbackgroundlevelsblgrowthcanrevealslowlydevelopinglongtermeruptionprecursors AT minorutakeo seismicbackgroundlevelsblgrowthcanrevealslowlydevelopinglongtermeruptionprecursors |