Slip distribution of the 2024 Noto Peninsula earthquake (MJMA 7.6) estimated from tsunami waveforms and GNSS data

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. Around Noto Peninsula, both offshore submarine and partially inland 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 53 stations in Noto Peninsula to estimate the slip amount and seismic moment on each of active faults. The results show that the 2024 coseismic slips were 3.5 m, 3.2 m, and 3.2 m on subfaults NT4, NT5 and NT6 of the JSPJ model, located on the northern coast of Noto Peninsula and dipping toward southeast. A smaller slip, 1.0 m, estimated on NT8 on the southwestern end of the 2024 rupture, may be attributed to its previous rupture during the 2007 Noto earthquake. The total length of these four faults is ~ 100 km, and the seismic moment is 1.90 × 1020 Nm (Mw = 7.5). Almost 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 in the NT2–NT3 region, but they are smaller than the potential magnitude (Mw 7.1) those faults can release in a tsunamigenic earthquake. 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 potential for future event. Graphical Abstract

A Multiplex Rupture Sequence under Complex Fault Network due to Preceding Earthquake Swarms during the 2024 Mw 7.5 Noto Peninsula, Japan, Earthquake

“…S1). Synthetic Aperture Radar (SAR) data (Geospatial Information Authority of Japan, 2024) show two major patches of deformation on the western side of the epicenter, including vertical displacement of up to about 4 m. A tsunami was also recorded at gauges along the coast (Fujii & Satake, 2024;Mizutani et al, 2024;Kutschera et al, 2024).…”

Effects of Source Directivity and Nonlinear Soil Behavior During the January, 1 2024 Noto Earthquake (Mw = 7.5)

“…Directivity effects during the 2024 Noto earthquake can be traced by changes in the waveforms of the acceleration time histories with increasing distance from the source towards ISK006 site; the waveforms are shown in Figure 5. The fault plane shown in Figure 1, was inclined to the Earth's surface at an angle of ∼ 45 • , with its western side located near the surface and its eastern side extending to the depth [Fujii, Yu. and Satake, 2024;Ishikawa, Yu.…”

A Multiplex Rupture Sequence Under Complex Fault Network Due To Preceding Earthquake Swarms During the 2024 Mw 7.5 Noto Peninsula, Japan, Earthquake

“…The dip directions of the aftershocks are not obvious, but they roughly show southeastward dips on the western side of the epicenter and northwestward dips on the eastern side (Figure S1 in Supporting Information S1). Synthetic Aperture Radar (SAR) data (Geospatial Information Authority of Japan, 2024) show two major patches of deformation on the western side of the epicenter, including vertical displacement of up to about 4 m. A tsunami was also recorded at gauges along the coast (Fujii & Satake, 2024;Kutschera et al, 2024;Mizutani et al, 2024).…”