5:15 PM - 6:45 PM
[SGD02-P06] Spatio-temporal changes in interplate slip in Suruga trough since 2012
Keywords:SSE, Tokai, Suruga trough
Abstract
Using GNSS data along the Suruga Trough, we estimated the interplate slip on the Phillipine Sea plate since 2012. As a result, the Tokai SSE occurred from 2013 to 2017, followed by the Shima Peninsula SSE from 2017 to 2020, and since 2022 SSE has occurred mainly on the Atsumi Peninsula. The SSE of the Atsumi Peninsula is expanding into the Tokai SSE area from around July 2023, and the DCFS in the Tokai blank area is increasing. Based on the cases of 2000-2005, 2013-2017, and 2023, the Tokai SSE recurrence interval is estimated to be approximately 10-13 years, and the duration time is estimated to be 5-6 years.
Introduction
Tokai SSE occurred from 2000 to 2005 adjacent to the Tokai seismic gap. Subsequently, three transitional crustal deformations were detected in the area along the Nankai Trough after the Tohoku Earthquake in 2012. In addition to correcting the effects of the 2011 off the Pacific coast of Tohoku Earthquake as viscoelastic deformation, we conducted an analysis along the Suruga Trough to estimate the spatiotemporal evolution of the state of the plate interface since 2012.
analysis method
The viscoelastic deformation of the 2011 off the Pacific coast of Tohoku Earthquake was corrected according to the results of Suito (2017), and the linear trend and periodicity from 2020 to 2022 were removed from the original data. The east-west, north-south, and vertical components of the 140 GNSS observation points relative to the Misumi site were used for time-dependent inversion. The plate shape is represented by a rectangular element consisting of two triangular elements based on Hirose (2008). The analysis period was from January 2012 to December 2023.
conclusion
From the time-series data, three transitional crustal deformations were detected in the Nankai Trough region since the Tohoku earthquake. The time-dependent inversion results suggest that the Tokai SSE occurred adjacent to the Tokai seismic gap during 2013-2017. In previous studies, the onset and termination times of the Tokai SSE were not clear, but by applying viscoelastic correction, the onset and termination times were estimated with high accuracy. Shima Peninsula SSE was estimated for 2017-2020. Kobayashi and Tsuyuki (2018) reported that SSE occurred in 2017-2018, but this study found that SSE continued until 2020. SSE has been occurring mainly in the Atsumi Peninsula since 2022. In the Atsumi Peninsula SSE, slip has spread to the Tokai SSE region since July 2023, and ΔCFS in the Tokai blank area is increasing.
Based on the cases of 2000-2005, 2013-2017, and 2023, the Tokai SSE occurrence interval is estimated to be approximately 10-13 years, and the duration time is estimated to be 5-6 years.
Using GNSS data along the Suruga Trough, we estimated the interplate slip on the Phillipine Sea plate since 2012. As a result, the Tokai SSE occurred from 2013 to 2017, followed by the Shima Peninsula SSE from 2017 to 2020, and since 2022 SSE has occurred mainly on the Atsumi Peninsula. The SSE of the Atsumi Peninsula is expanding into the Tokai SSE area from around July 2023, and the DCFS in the Tokai blank area is increasing. Based on the cases of 2000-2005, 2013-2017, and 2023, the Tokai SSE recurrence interval is estimated to be approximately 10-13 years, and the duration time is estimated to be 5-6 years.
Introduction
Tokai SSE occurred from 2000 to 2005 adjacent to the Tokai seismic gap. Subsequently, three transitional crustal deformations were detected in the area along the Nankai Trough after the Tohoku Earthquake in 2012. In addition to correcting the effects of the 2011 off the Pacific coast of Tohoku Earthquake as viscoelastic deformation, we conducted an analysis along the Suruga Trough to estimate the spatiotemporal evolution of the state of the plate interface since 2012.
analysis method
The viscoelastic deformation of the 2011 off the Pacific coast of Tohoku Earthquake was corrected according to the results of Suito (2017), and the linear trend and periodicity from 2020 to 2022 were removed from the original data. The east-west, north-south, and vertical components of the 140 GNSS observation points relative to the Misumi site were used for time-dependent inversion. The plate shape is represented by a rectangular element consisting of two triangular elements based on Hirose (2008). The analysis period was from January 2012 to December 2023.
conclusion
From the time-series data, three transitional crustal deformations were detected in the Nankai Trough region since the Tohoku earthquake. The time-dependent inversion results suggest that the Tokai SSE occurred adjacent to the Tokai seismic gap during 2013-2017. In previous studies, the onset and termination times of the Tokai SSE were not clear, but by applying viscoelastic correction, the onset and termination times were estimated with high accuracy. Shima Peninsula SSE was estimated for 2017-2020. Kobayashi and Tsuyuki (2018) reported that SSE occurred in 2017-2018, but this study found that SSE continued until 2020. SSE has been occurring mainly in the Atsumi Peninsula since 2022. In the Atsumi Peninsula SSE, slip has spread to the Tokai SSE region since July 2023, and ΔCFS in the Tokai blank area is increasing.
Based on the cases of 2000-2005, 2013-2017, and 2023, the Tokai SSE occurrence interval is estimated to be approximately 10-13 years, and the duration time is estimated to be 5-6 years.