Journal
TECTONOPHYSICS
Volume 600, Issue -, Pages 27-40Publisher
ELSEVIER SCIENCE BV
DOI: 10.1016/j.tecto.2012.12.015
Keywords
Low-frequency earthquakes; Semi-volcanic LFEs; Western Japan; Automated event detection; Hypocenter relocation; Size-frequency statistics
Categories
Funding
- JSPS [23244090, 12J09135]
- MEXT [21107007]
- Grants-in-Aid for Scientific Research [21107007, 23244090, 12J09135] Funding Source: KAKEN
Ask authors/readers for more resources
In western Japan, relatively small (M<2) deep low-frequency earthquakes (LFEs) occur at around 30 km depth, radiating seismic waves mainly in the frequency band of 2-8 Hz. The LFEs are categorized into three types based on their locations: tectonic LFEs on plate boundaries, volcanic LFEs beneath active volcanoes, and isolated intraplate LFEs located far from either plate boundaries or active volcanoes. Despite our lack of understanding of the LFEs, their spatial distributions suggest that tectonic, volcanic, and isolated intraplate LFEs are physically related to interplate megathrust earthquakes, volcanic eruptions, and large inland earthquakes, respectively. The present paper characterizes the seismicity of the three types of LFEs in five regions based on a more complete catalog, thanks to automated event detection and precise relocation using waveform correlation. The results show that isolated intraplate LFEs are more similar to volcanic LFEs than to tectonic LFEs. The volcanic and isolated intraplate LFEs are insensitive to tidal stress, are characterized by power-law magnitude frequency statistics such as the Gutenberg-Richter relation, and are distributed mainly in small vertical clusters, while the tectonic LFEs are modulated by tidal stress, are limited in size, and are distributed along the plate boundary. Hence, we propose that isolated intraplate LFEs should be named semi-volcanic LFEs. Since tectonic LFEs and volcanic LFEs are thought to be related to the fluid existence and fluid movements, respectively, isolated intraplate (semi-volcanic) LFEs may be related to crustal fluid movements in the source area. (C) 2012 Elsevier B.V. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available