3D Fault Model Sheds Light on Uplift Dynamics in 2024 Noto Peninsula Earthquake.

On January 1, 2024, a powerful 7.5-magnitude earthquake struck Japan's Noto Peninsula, located in the north-central region of the country. The disaster caused significant damage, largely due to dramatic ground uplift—vertical movement of the earth's surface resulting from tectonic activity. In certain locations, this uplift reached up to five meters, varying widely across affected areas.

To better understand the mechanisms behind this variation, Japanese scientists created a highly detailed three-dimensional simulation of the fault system involved in the earthquake. Utilizing advanced computational techniques and extensive pre-earthquake observational data, the research team sought to explore how fault geometry—specifically the orientation and structure of the fault lines—influenced the earthquake's impact.

The study, published in Earth, Planets and Space, was led by Ryosuke Ando, an associate professor at the University of Tokyo’s Graduate School of Science. “Our goal was to investigate what controls the magnitude and distribution of fault slip and the resulting surface uplift,” said Ando. “The variations we observed during the Noto Peninsula earthquake were striking.”

The simulation incorporated data gathered prior to the earthquake, including detailed characteristics of the fault system and the record of smaller seismic events in the years leading up to 2024. These smaller quakes, part of a localized seismic swarm, were key to understanding the stress conditions in the region.

Three main faults were identified as being responsible for the quake: the Monzen Fault, the Noto Peninsula Hoku-gan Fault Zones, and the Toyama Trough Sei-en Fault. The first two dip toward the southeast, while the third dips northwest. These are classified as conjugate faults, meaning they move laterally in opposite directions. The inclination of each fault—known as its dip—along with its orientation and motion direction, were central to the creation of the model.

By incorporating this data, the researchers were able to replicate the spatial differences in uplift experienced during the quake. Notably, the model revealed that significant vertical displacement occurred near sections of the fault where it deviated from its more horizontal alignment. These localized bends played a major role in intensifying the effects in some areas.

“Our use of a supercomputer enabled the simulation of complex, irregular fault structures,” Ando explained. “We found that the relative positioning of these faults to the compressional forces in the tectonic plate strongly influenced the rupture dynamics and uplift patterns.”

Looking forward, the team aims to use this modeling approach to enhance predictive tools for future earthquakes. By accurately simulating fault slip behaviors based on known fault geometries, researchers hope to better assess seismic hazards before large earthquakes occur.

“This study demonstrates how detailed fault modeling can inform hazard assessments,” Ando added. “Understanding how and where uplift is likely to occur could be key to mitigating damage in future seismic events.”

This research marks a significant step toward integrating fault geometry into earthquake risk forecasting, offering a clearer picture of how Earth's hidden structures shape the surface impacts of major seismic events.

Source:https://phys.org/news/2025-04-noto-quake-3d-dimension-earthquake.html

This is non-financial/medical advice and made using AI so could be wrong.