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Rupture Process and Consequences of the 2024 Noto Peninsula Earthquake

Description: 

The Noto Peninsula earthquake occurred in the northern part of the Noto Peninsula at 16:10:10 (local time, UTC+9) on January 1, 2024, causing extensive and severe damage. To construct a rupture process model for this earthquake, we first built a fault model, which consists of northeastern (NE) and southwestern (SW) segments, based on the known active fault traces, aftershock distribution and reported focal mechanisms. The hypocenter (rupture initiation point) was located on the NE segment, whose strike and dip are consistent with the focal mechanism of the mainshock. The strike and dip of the SW segment were mainly determined according to the aftershock distribution. We next performed a joint source inversion using teleseismic waveforms from the Global Seismographic Network and strong motion waveforms recorded by K-NET and KiK-net. The results showed that the mainshock ruptured with a duration of about 50 s, releasing a total seismic moment of 2.4×10²⁰ Nm, which corresponds to an M_w of 7.5. The rupture began with small slips on the NE segment in the first 10 s. It then propagated northeastward and the SW segment began to rupture. These two beginnings would correspond to two events determined at 16:10:10 and 16:10:23 by the JMA. Large slip zones (asperities) with maximum slips of 5 and 6 meters were formed in the shallow parts of both NE and SW segments. The SW asperity roughly covers the northern part of the peninsula and is responsible for the strong ground motion and resulting damage there. It is also responsible for the large uplift of the northern coast of the peninsula. On the other hand, since the NE asperity is under the sea, it is responsible for large tsunamis and resulting damage on the northeastern coast.

Session: The 2024 Magnitude 7.5 Earthquake and the Associated Earthquake Swarm Beneath the Noto Peninsula, Central Japan - I

Type: Oral

Date: 5/3/2024

Presentation Time: 08:00 AM (local time)

Presenting Author: Kazuki

Student Presenter: No

Invited Presentation: 

Authors