Quantectum’s Forecasting Models and 2024 Noto Peninsula Earthquake

On January 1, 2024, at 15:10 local time, a powerful magnitude 7.5 earthquake struck 7 km (4.3 mi) north-northwest of Suzu, situated on the Noto Peninsula in Ishikawa Prefecture, Japan. It hit at a depth of 10 km (6.2 mi) at the exact location 37.50° LAT, 137.24° LON.  The 2024 Noto Peninsula Earthquake (Reiwa 6-nen Noto-hantō Jishin 令和6年能登半島地震) and subsequent aftershocks resulted in extensive damage, numerous injuries, and a tragic toll of 232 lives.

In this blog, we will explore how much Quantectum’s earthquake forecasting models are correlated with the earthquake, focusing on ground motion, peak ground acceleration, peak ground velocity, shear traction model, ensemble models, dynamic traction model, T-synchronization model, atmospheric chemical potential (ACP), and shear stress.

Picture 1: Location of the magnitude 7.5 Noto Peninsula Earthquake (January 1, 2024).

Earthquake Ground Motion

The earthquake reached level VIII macroseismic intensity, associated with violent shaking and potential heavy damage to the infrastructure. The macroseismic intensity scale is a way of qualitatively describing the effects of an earthquake at specific locations based on observed damage, human perception, and other factors. The scale typically ranges from I (not felt) to XII (total destruction). Potentially exposed cities were Takaoka (pop. 170,000) distance of 85 km (52 mi), Toyama (pop. 416,000) distance of 89 km (55 mi), Joetsu (pop. 189,000) distance of 96 km (59 mi), Kanazawa (pop. 466,000) distance of 114 km (70 mi), and Nagano (pop. 360,000) 126 km (78 mi). The estimated macroseismic intensities in these cities varied from III (weak) to V (moderate), according to Quantectum’s Macroseismic Intensity map.

Picture 2: Quantectum’s Macroseismic Intensity Map for the magnitude 7.5 Noto Peninsula earthquake (January 1, 2024).

The peak ground acceleration, which refers to the maximum acceleration experienced by the ground during the earthquake, reached 50% g, indicating a significant and potentially damaging level of ground motion during the earthquake.

Picture 3: Quantectum’s Peak Ground Acceleration for the magnitude 7.5 Noto Peninsula earthquake.

The peak ground velocity, which provides information about the speed at which the ground is moving during an earthquake, reached 58 cm/s, indicating intense shaking and contributing to the assessment of potential damage to structures and infrastructure.

Together with peak ground acceleration, peak ground velocity helps in understanding the dynamic characteristics of the seismic event and its impact on the surrounding environment.

Picture 4: Quantectum’s Peak Ground Velocity for magnitude 7.5 Noto Peninsula earthquake.

Quantectum’s Earthquake Forecasting Models

Quantectum runs the most advanced Physical Earthquake Forecasting Models of global time-dependent tectonic stresses, local tectonic instabilities of faults and fault zones, critical regions, and tectonic tractions. These models solve the fundamental physical equations that govern the Earth's system and offer valuable insights into the relationship between physical forces in the Earth's crust and observed earthquakes.

Our advanced Physical Earthquake Forecasting Models help us understand how forces in the Earth's crust trigger earthquakes. However, it's important to note that they can be sensitive to the initial data, occasionally resulting in timing and location inaccuracies.

In continuation, we’ll dive deeper into some of the most important models using the case of the 2024 Noto Peninsula earthquake.

Shear Traction Model

The default shear traction model calculated by Quantectum is a specific model used to calculate the force parallel to a surface that acts to slide one block of rocks relative to an adjacent block. Already at the beginning of December 2023, this model indicated the presence of the rotational singularity (see orange dashed ellipse on the picture below) from approximately January 22, 2023, until January 3, 2024, in the region of the Noto Peninsula earthquake occurrence.

The epicenter of the magnitude 7.5 Noto Peninsula event was just at the edge of the large shear traction cloud spanning through the regions of Hokkaido and Honshu, towards the Izu Islands.

Picture 5: Shear traction model for the 2024 Noto Peninsula earthquake.

Rotational singularities occur at the interception of tectonic waves with similar wavelengths. In such regions, the torques on tectonic blocks are very high. From Quantectum’s past analysis, we know that rotational singularities mean a highly increased probability of strong M6+ earthquake-triggering. In Japan, the presence of a rotational singularity means approximately 60 % chance of having at least one M6+ earthquake.

Ensemble Models

The Quantectum ensemble approach, where we generate multiple ensemble models, showed that several ensemble models indicated a high ensemble likelihood of the rotational singularity in Japan in the second half of December 2023 and the first days of January 2024. This is illustrated in the graph below.

The Agresti-Coul probability intervals suggested a 60 - 100 % probability that the shear traction in the Honshu region would exceed the value of 0.7. This threshold of 0.7 is a critical value and the forecast indicates a high likelihood that the actual shear traction will be greater than this specified value.

Agresti-Coul probability intervals are a statistical method used to estimate the range within which shear traction is likely to fall, based on a sample of data.

Picture 6: Ensemble models for the 2024 Noto Peninsula earthquake.

Dynamic Traction Model

The Quantectum dynamic traction model, which calculates tractions exerted on the tectonic faults due to global seismic activity of tectonic waves, at the end of December showed a huge anomaly of dynamic traction in the vast region of Kamchatka, Kuril Islands, Hokkaido, and the Sea of Japan. This anomaly was similar to the one that occurred before the Tohoku 2011 magnitude 9.1 earthquake.

Picture 7: Quantectum’s dynamic traction model for the region of the 2024 Noto Peninsula earthquake.

Time-synchronization Model

The Quantectum's T-synchronization model describes local tectonic instabilities of tectonic faults and tectonic zones. It is based on the synchronization of seismic sequences in a specific time dimension. This model suggested that the epicentral region of the magnitude 7.5 2024 Noto Peninsula earthquake was highly unstable. The earthquake occurred at the edge of a small critical region, illustrated in red in the image below. This critical region is an area where the synchronization of seismic activity particularly contributed to the heightened instability.

Picture 8: Quantectum’s Time-synchronization model for the 2024 Noto Peninsula earthquake.

The maximum of the T-synchronization was forecasted to occur on January 05, 2024. The image below illustrates the T-synchronization function (red line) in December 2023 and January 2024. Earthquakes within distances of 100 km, 200 km, and 500 km are illustrated with the red, green, and blue columns respectively. This graph helps us to understand the relationship between the spatiotemporal distribution of the seismic events and the temporal development of the T-synchronizations.

Picture 9: T-synchronization function (red line) of seismic sequences near the western coast of Honshu. The colored columns denote the occurred earthquakes in the wider region of the epicenter.

Atmospheric Chemical Potential (ACP)

Quantectum ACP models suggest that shortly before the 2024 Noto Peninsula earthquake, a huge fluctuation of the ACP occurred, indicating emissions of radon from the ground in the region of Honshu. The graph below illustrates the shear traction field (red line) and the ACP fluctuations (blue line). From our past experience, we know that ACP fluctuations often occur in correlation with the occurrence of rotational singularities and fast jumps / drops of the shear traction field associated with them.

Picture 10: Graph of the Atmospheric Chemical Potential (ACP) in Japan region from December 8, 2023, to January 12, 2024.

The next image below illustrates the ACP anomaly in the Honshu region on December 30, 2023, at 15:00 UTC. The red color indicates a strong anomaly in the region and is marked with a white arrow.

Picture 11: Atmospheric Chemical Potential (ACP) in Japan region from December 8, 2023, to January 12, 2024

Shear Stress

Shear stress is a type of stress that acts parallel to a surface, causing one part of the material to slide past another. Quantectum tectonic stress model indicated that the tectonic shear stress in central and southern Japan increased in December 2023. As of the second middle of January 2024, the region is under high to very high shear stresses and the NW-SE-directed horizontal compression. This indicates that there is a significant amount of tectonic stress in the region, particularly in the form of horizontal compression, where forces are pushing from opposite directions horizontally.

The focal mechanism of the latest event, referring to the orientation and characteristics of the fault that caused the earthquake, is in agreement with this model, which supports the validity and accuracy of the Quantectum model in this context.

Picture 12: Normalized shear stress in the Japan region.

Conclusion

The magnitude 7.5 Noto Peninsula earthquake on January 1, 2024, was well correlated with the Quantectum models. Two weeks before the events, a rotational singularity in the Japan region caused a strong jump in the shear traction field associated with significant fluctuations of the ACP field (radon emissions). A few days before the event, also the dynamic traction caused by the global seismic activity of tectonic waves produced a huge anomaly in the region of Kamchatka, Kuril Islands, Hokkaido, and the Sea of Japan.

Both, the shear traction and dynamic traction, triggered a strong earthquake within a highly unstable T-synchronized tectonic zone near the West coast of Honshu on January 1, 2024. The earthquake was also preceded by significant ACP precursory anomalies that indicated extensive radon emissions from the ground and by strongly elevated shear stress accumulated in the Earth’s crust.

Similar cases in Japan will allow Quantectum to gain better knowledge about how large earthquakes are being triggered in the region. This knowledge will undoubtedly increase our future forecasting abilities.