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

Abstract

A devastating earthquake with moment magnitude 7.5 occurred in the Noto Peninsula, central Japan. We estimate the rupture evolution of this earthquake from teleseismic P-wave data using the potency-density tensor inversion method, which can give spatiotemporal slip distribution including the information on fault orientations. The result shows a long and quiet initial rupture phase, which overlaps the regions of the preceding earthquake swarms and the associated aseismic deformation. The following three major rupture episodes evolve on segmented, differently oriented faults, which are bounded by the initial rupture region. The irregular initial rupture process followed by the multi-scale rupture growth are considered to be controlled by the preceding seismic and aseismic processes and the geometric complexity of fault system. Such a discrete rupture scenario, including the triggering of an isolated fault rupture, add critical inputs on the assessment of strong ground motion and associated damages for future earthquakes.

Fault Model of the 2024 Noto Peninsula Earthquake Based on Aftershock, Tsunami, and GNSS Data

“…Since the hypocenter is the origin of the fault rupture, our model implies that the small slip occurred at the hypocenter, and then the rupture propagated bilaterally with large slips. This is consistent with the fault rupture model estimated using teleseismic P-wave (Okuwaki et al 2024).…”