Subsurface structures may control the migration of magma beneath a volcano. We used high-resolution seismic tomography to image a low- P-wave velocity (Vp) zone beneath Unzen Volcano, Japan, at depths of 3-16 km beneath sea level. The top of this low-Vp zone is located beneath Mt. Fugendake of Unzen volcano, which emitted 0.21 km of dacitic magma as lava domes and pyroclastic flows during eruptions in 1990-1995. Based on hypocenter migrations prior to the 1990-1995 eruptions and modeled pressure source locations for recorded crustal deformation, we conclude that the magma for the 1990-1995 eruptions migrated obliquely upward along the top of the low-Vp zone. As tectonic earthquakes occurred above the deeper part of the low-Vp zone, the deep low-Vp zone is interpreted to be a high-temperature region (> 400 °C) overlying the brittle-ductile transition. By further considering Vs and Vp/Vs structures, we suggest that the deeper part of the low-Vp zone constitutes a highly crystalized magma-mush reservoir, and the shallower part a volatile-rich zone.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8599693 | PMC |
| http://dx.doi.org/10.1038/s41598-021-00481-6 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Seismic velocity structure of Unzen Volcano, Japan, and relationship to the magma ascent route during eruptions in 1990-1995.
Sci Rep
November 2021
Institute of Seismology and Volcanology, Faculty of Science, Kyushu University, Shin'yama, Shimabara, Nagasaki, 855-0843, Japan.
Subsurface structures may control the migration of magma beneath a volcano. We used high-resolution seismic tomography to image a low- P-wave velocity (Vp) zone beneath Unzen Volcano, Japan, at depths of 3-16 km beneath sea level. The top of this low-Vp zone is located beneath Mt.
View Article and Find Full Text PDFActive Volcanism Revealed from a Seismicity Conduit in the Long-resting Tatun Volcano Group of Northern Taiwan.
Sci Rep
April 2020
National Center for Research on Earthquake Engineering, National Applied Research laboratories, Taipei, Taiwan.
Abundant earthquakes clustered within a particular zone often reflect an active geological feature, such as clustering seismicity along a fault zone and a huge number of volcanic-earthquakes around the erupting conduit. Herein we perform a double-difference tomographic inversion and relocate the seismicity at the long-resting Tatun volcano group (TVG) in northern Taiwan. A dramatic improvement of the earthquake location model surprisingly show that, from 2014 to 2017, two clustered seismic zones are identified in the TVG.
View Article and Find Full Text PDFPossible control of subduction zone slow-earthquake periodicity by silica enrichment.
Nature
June 2014
Department of Earth and Planetary Science and Berkeley Seismological Laboratory, University of California, Berkeley, California 94720-4767, USA.
Seismic and geodetic observations in subduction zone forearcs indicate that slow earthquakes, including episodic tremor and slip, recur at intervals of less than six months to more than two years. In Cascadia, slow slip is segmented along strike and tremor data show a gradation from large, infrequent slip episodes to small, frequent slip events with increasing depth of the plate interface. Observations and models of slow slip and tremor require the presence of near-lithostatic pore-fluid pressures in slow-earthquake source regions; however, direct evidence of factors controlling the variability in recurrence times is elusive.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!