[M-IS09] Interdisciplinary studies on pre-earthquake processes

[MIS09-P06] New Developments in Crustal Deformation Research Using Pseudo-Strain Gauges with GNSS Data

*野田 洋一¹、服部 克巳^2,3,4、藤縄 幸雄⁵、吉野 千恵² (1.千葉大学大学院融合理工学府、2.千葉大学大学院理学研究院、3.千葉大学環境リモートセンシング研究センター、4.千葉大学災害治療学研究所、5.一般社団法人防災減災技術開発機構)

An investigation of the relationship between changes in the correlation coefficients of the orthogonal components of four-component borehole strainmeter data and earthquakes in China reported that the correlation coefficients, which are normally close to 1, decreased to 0.2 just before several significant earthquakes. In addition, a study of the relationship between network connectivity and earthquakes using correlation coefficients between stations of multiple borehole strainmeter data reported that anomalies tended to increase 20 days prior to earthquakes. In Japan, 67 strain gauges have been installed, but there is a limit to the number and regional bias. Therefore, using the GNSS continuous observation system (GEONET) deployed by the Geospatial Information Authority of Japan (GSI) at approximately 1,300 locations throughout Japan, we decided to construct a pseudo-strain gauge consisting of four GEONET observation points to index the amount of crustal deformation. Then, we investigated the relationship between the network connectivity calculated from the correlation coefficients among the pseudo-strainmeter stations and earthquakes. In this report, we report the results of our attempts to extract variations before and after the 2016 Kumamoto earthquake (Mw 7.0), the 2011 off the Pacific coast of Tohoku earthquake (Mw 9.0), and the 2024 Noto Peninsula earthquake (Mw 7.5).