Elucidation of activity of deep low-frequency earthquakes in subduction zone

2016 Fiscal Year Final Research Report

• Project/Area Number: 26400447
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Solid earth and planetary physics
• Research Institution: The University of Tokyo (2016); Nagoya University (2014-2015)
• Principal Investigator: Kato Aitaro 東京大学, 地震研究所, 准教授 (20359201)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: 低周波地震 / ゆっくり滑り / スロー地震

Outline of Final Research Achievements

In the present study, we performed a systematic search for events with seismograms similar to those observed for a number of low-frequency earthquakes (LFEs), those have taken place at the down-dip extension of locked region associated with megathrust earthquake along the Nankai Trough. We constructed a new catalog of LFEs from April 2004 to August 2015 (during 11.5 years). Then, the analysis of this catalog leaded to new understanding of spatial-temporal evolution of LFEs. For example, we clearly showed that high-speed migrations of LFEs repetitively occur during a short-term slow slip events. It is interesting that the high-speed migrations of LFEs evolve in a diffusional manner; i. e., the migration front speed decays with ongoing time. Furthermore, we found out a lateral variation of slow-slip recurrence property along the deep tremor belt in Nankai Trough.

Free Research Field

地震学