5:15 PM - 6:45 PM
[U15-P97] Active structure investigation for elucidating the paleoseismicity in the northeastern part of the Noto Peninsula
Keywords:marine terrace, active submarine fault, excavation, uplift
The lower marine terraces along the northeastern coast of the Noto Peninsula suggests co-seismic uplift caused by active submarine faults (Shishikura et al., 2020). However, the emergence age of terraces is not clear. In this study, we carried out topographical survey and excavation of lower marine terraces to estimate the paleoseismicity in the northeastern part of the Noto Peninsula. The investigation areas are Matsunagi and Kawaura areas in Suzu City, based on topographical interpretation and geological survey. These areas are dominated by the Lower1, Lower2, and Lower3 marine terraces. We carried out boring or pit excavations on these terraces, geological observations and C-14 dating.
Based on the difference in topographic cross-sectional measurements before and after the 2024 Noto Peninsula Earthquake in the areas, uplift is 1.3-1.5 m in the Matsunagi area and approximately 1.4 m in the Kawaura area. The altitude of lower terrace surface (L3 surface) in both areas are approximately 4.5 m and approximately 5.5 m and was not formed by uplift of the same magnitude as the 2024 Noto Peninsula Earthquake. On the other hand, the height difference between each surface is approximately 1 to 2 meters, which is the same level of uplift as the 2024 Noto Peninsula Earthquake. In addition, the C-14 age of the humus layer at a depth of around 1.9 m in the L2 deposits in the Matsunagi area is 1830-1720 cal BP.
In the future, it may be possible to estimate the distribution of displacement and paleoseismicity of active submarine faults off the coast of the Noto Peninsula by investigating the distribution height of low terrace surfaces and the emergence age.
This work was supported by JSPS KAKENHI Grant Number JP23K17482.
Based on the difference in topographic cross-sectional measurements before and after the 2024 Noto Peninsula Earthquake in the areas, uplift is 1.3-1.5 m in the Matsunagi area and approximately 1.4 m in the Kawaura area. The altitude of lower terrace surface (L3 surface) in both areas are approximately 4.5 m and approximately 5.5 m and was not formed by uplift of the same magnitude as the 2024 Noto Peninsula Earthquake. On the other hand, the height difference between each surface is approximately 1 to 2 meters, which is the same level of uplift as the 2024 Noto Peninsula Earthquake. In addition, the C-14 age of the humus layer at a depth of around 1.9 m in the L2 deposits in the Matsunagi area is 1830-1720 cal BP.
In the future, it may be possible to estimate the distribution of displacement and paleoseismicity of active submarine faults off the coast of the Noto Peninsula by investigating the distribution height of low terrace surfaces and the emergence age.
This work was supported by JSPS KAKENHI Grant Number JP23K17482.