Tsunamigenic fault structures revealed in the 2024 Noto earthquake (M7.6) rupture area

On January 1, 2024, a large-magnitude (M7.6) reverse-fault earthquake struck the Noto Peninsula, Japan, generating a tsunami that caused extensive coastal damage. The source fault, inferred from aftershock distributions by the Japan Meteorological Agency, extends approximately 150 km from the peninsula’s western coast to the northeastern offshore region. High-resolution pre-stack depth migrated seismic profiles reveal a large deformation zone (LDZ) within the 2024 coseismic rupture area. This ~ 2.5–3.8 km wide and ~ 30 km long LDZ consists of steeply southeast-dipping reverse faults (~ 50°–75°), which may represent shallow extensions of the deeper seismogenic listric fault, as well as branching faults suggestive of a local strike-slip component. Numerical simulations of tsunami generation suggest that a coseismic slip of 6–7 m along the reverse fault, followed by reactivation of the LDZ, could have produced up to 3 m of seafloor uplift and triggered subsequent tsunamis. In addition, we identified northwest-dipping reverse faults (~ 50°–55°) that appear to be active but exhibited little coseismic slip during the 2024 event. Our findings provide the first detailed characterization of tsunamigenic fault structures within the rupture area of the 2024 Noto earthquake.