Slip Distribution of the 2024 Noto Peninsula Earthquake (MJMA 7.6) Estimated from Tsunami Waveforms and GNSS Data

Abstract

Abstract The 1 January 2024 Noto-Hanto (Noto Peninsula) earthquake (MJMA 7.6) generated strong ground motion, large crustal deformation and tsunamis that caused significant damage in the region. Off Noto Peninsula, offshore submarine active faults have been identified by previous projects: Ministry of Land, Infrastructure, Transport and Tourism (MLIT) and Japan Sea Earthquake and Tsunami Research Project (JSPJ). We inverted the tsunami waveforms recorded on 6 wave gauges and 12 tide gauges around Sea of Japan and the GNSS data recorded at 13 stations in Noto Peninsula to estimate the slip amount and seismic moment on each of active faults. The results show that 2024 coseismic slips were 4 m, 3 m, and 3 m on subfautls NT 4, NT5 and NT6 of the JSPJ model, located on the northern coast of Noto Peninsula and dipping toward southeast. A smaller slip, 1.5 m, estimated on NT 8 on the northwestern edge, may be because of its previous rupture during the 2007 Noto earthquake. The total length of these four faults is ~ 100 km, and the seismic moment is 1.86 × 1020 Nm (Mw = 7.4). No slip was estimated on the northeastern subfaults NT2 and NT3, which dip northwestward, opposite to NT4-NT5-NT6, and western subfault NT8. Aftershocks including the MJMA 6.1 event occurred on the NT2-NT3 region, hence these two faults may have a potential to produce larger earthquake and associated tsunamis. Similar features are also found for the MLIT model; the 2024 slip was only on F43 along the northern coast of Noto Peninsula, and northeastern F42 did not rupture, leaving the future potential.