[U-15] The 2024 Noto Peninsula Earthquake (1:J)

[U15-P48] Quick response survey cruises for the 2024 Noto Peninsula Earthquake by R/V Hakuho-maru (KH-24-JE01 and KH-24-JE02C)

*Koichiro Obana¹, Tsutomu Takahashi¹, Yoshio Murai², Ryota Hino³, Yusaku Ohta³, Ryosuke Azuma³, Toshinori Sato⁶, Masanao Shinohara⁴, Hajime Shiobara⁴, Takehi Isse⁴, Tomoaki Yamada⁴, Takeshi Akuhara⁴, Kazuo Nakahigashi⁵, Hisatoshi Baba⁷, Yoshihiro Ito⁸, Yusuke Yamashita⁸, Tada-nori Goto⁹, Hiroshi Yakiwara¹⁰, Yukihiro Nakatani¹⁰, Takafumi Kasaya¹, Yusuke Ohta¹, Junji Kaneko¹, Satoshi Ogura¹, Tetsuo No¹, Gou Fujie¹, Shuichi Kodaira¹, KH-24-JE01 and KH-24-JE02C cruise participants (1.Japan Agency for Marine-Earth Science and Technology, 2.Hokkaido Univeristy, 3.Tohoku University, 4.Earthquake Research Institute, University of Tokyo, 5.Tokyo University of Marine Science and Technology, 6.Chiba University, 7.Tokai University, 8.Disaster Prevention Research Institute Kyoto University, 9.University of Hyogo, 10.Kagoshima University)

Keywords:Noto Peninsula Earthquake, R/V Hakuho-maru, OBS, OBEM, Bathymetric survey

The 2024 Noto Peninsula earthquake (M7.6) that occurred on January 1, 2024 in Noto Peninsula, Japan, and the accompanying tsunami caused extensive damage in the Noto Peninsula and surrounding areas. The seismic activity in the northeastern part of the Noto Peninsula has been active in recent years, including M6.5 earthquakes on May 5, 2023. While the seismic activity until December 2023 was mainly in the northeastern Noto Peninsula, seismic activity after January 1, 2024 has been expanding over an area extending approximately 150 km in a northeast-southwest direction from the offshore area northeast of the Noto Peninsula to the west of the Noto Peninsula. Detailed information on seismic activity in the offshore area is important for understanding the source fault of the earthquake. We conducted two research cruises by R/V Hakuho-maru (KH-24-JE01 from 16 to 23, January 2024 and KH-24-JE02C from 19 February to 1 March) as a part of the quick response survey for the 2024 Noto Peninsula Earthquake. Following these cruises, the third cruise was conducted in March 2024, as a joint usage/research cruise.
During the first cruise KH-24-JE01 in January 2024, a total of 34 ocean bottom seismographs (OBSs), which consisted of 26 SPOBSs, 5 LTOBSs, and 3 BBOBSs, were deployed offshore northeast of the Noto Peninsula. Two OBEMs were also deployed. During the second cruise (KH-24-JE02C), 26 SPOBSs and 2 OBEMS deployed during the first cruise were recovered, and 20 OBSs and 5 OBEMs were deployed. We also conducted a bathymetric survey covering an area from offshore northeast of the Noto Peninsula to Toyama Bay during the two cruises. Data from the SPOBSs recovered during the second cruise have provided preliminary results of the offshore seismicity. Other data will be analyzed as appropriate.