5:15 PM - 6:45 PM
[U15-P43] Characteristics of seismic intensity distribution of "The 2024 Noto Peninsula Earthquake"
Keywords:The 2024 Noto Peninsula Earthquake, indication of seismic intensity distribution in map form, IXAC41, seismic intensity
1. Background
Seismic activity has continued in the Noto region of Ishikawa Prefecture since December 2020, and the earthquake in the Noto region of Ishikawa Prefecture that occurred at around 16:10 on January 1, 2024 caused the "Wajimashi-Monzenmachi-Hashiride" (*1) and "Shikamchi-Kano" (*2), a seismic intensity of 7 was observed, and the strong shaking caused extensive damage in a wide area, mainly in the Noto Peninsula. The Japan Meteorological Agency has named this earthquake and a series of seismic activities since December 2020 "The 2024 Noto Peninsula Earthquake". From February 1, 2023, the indication of seismic intensity distribution in map form will be provided with higher resolution and higher accuracy than before. Specifically, by increasing the resolution from the conventional 1km mesh to a 250m mesh, it is now possible to understand the seismic intensity distribution in more detail. In addition, to improve accuracy, by using seismic intensity prediction technology from emergency earthquake early warnings as a method for estimating seismic intensity, we can create highly accurate indication of seismic intensity distribution in map form even if there are observation points where seismic intensity data is not available due to power outages etc, and it is now possible to provide.
2. Effectiveness of "Indication of seismic intensity distribution in map form"
Regarding the earthquake that occurred in the Noto region of Ishikawa Prefecture at around 16:10 on January 1, 2024, the indication of seismic intensity distribution in map form (IXAC41) was released approximately 10 minutes after the earthquake occurred. The indication of seismic intensity distribution in map form shows that almost the entire Noto Peninsula may experience a seismic intensity of 6 lower or higher, and wooden buildings with low earthquake resistance may collapse, and landslips and landslides may occur in these areas. We were able to grasp this possibility shortly after the earthquake occurred. In addition, there are three seismic intensity observation points that were announced in the earthquake information as "The seismic intensity is thought to be 5 lower or higher, but the seismic intensity is not currently available.", but we investigated the seismic intensity at these seismic intensity observation points that were later obtained. However, it was found that the estimated seismic intensity at these seismic intensity observation points almost matched the indication of seismic intensity distribution in map form released on the day of the earthquake. This shows that the indication of seismic intensity distribution in map form is effective as a tool for understanding seismic intensity in areas where seismic intensity data is not available due to obstacles or other reasons.
3. About the characteristics of shaking
We also investigated the characteristics of shaking at seismic intensity observation points. The earthquake that occurred in the Noto region of Ishikawa Prefecture at around 16:10 on January 1, 2024 caused tremors equivalent to seismic intensity 5 or higher in Wajimashi-Hugeshimachi (*3) and Suzushi-Misakimachi (*3). It was estimated that it took about 50 seconds. On the other hand, in the earthquake off the coast of the Noto Peninsula that occurred at around 23:20 on January 6, 2024, a seismic intensity of lower 6 was observed only at Shikamchi-Kano, and only a seismic intensity of 3 or lower was observed at other seismic intensity observation points. When we investigated the earthquake waveforms in Shikamchi-Kano, we found that the period of strong shaking was extremely short and had harmonic characteristics.
[Website of "Indication of seismic intensity distribution in map form" ]
URL: https://www.jma.go.jp/bosai/map.html#contents=estimated_intensity_map
*1 Seismic intensity meter installed by Ishikawa Prefecture
*2 K-NET observation point established by the National Research and Development Agency, National Research Institute for Earth Science and Disaster Prevention.
*3 Seismic intensity meter installed by the Japan Meteorological Agency
Acknowledgment
We used data from seismic intensity meters installed by each local government in the seismic intensity information network and data from the strong motion observation network maintained by the National Research and Development Agency, National Research Institute for Earth Science and Disaster Prevention.
Seismic activity has continued in the Noto region of Ishikawa Prefecture since December 2020, and the earthquake in the Noto region of Ishikawa Prefecture that occurred at around 16:10 on January 1, 2024 caused the "Wajimashi-Monzenmachi-Hashiride" (*1) and "Shikamchi-Kano" (*2), a seismic intensity of 7 was observed, and the strong shaking caused extensive damage in a wide area, mainly in the Noto Peninsula. The Japan Meteorological Agency has named this earthquake and a series of seismic activities since December 2020 "The 2024 Noto Peninsula Earthquake". From February 1, 2023, the indication of seismic intensity distribution in map form will be provided with higher resolution and higher accuracy than before. Specifically, by increasing the resolution from the conventional 1km mesh to a 250m mesh, it is now possible to understand the seismic intensity distribution in more detail. In addition, to improve accuracy, by using seismic intensity prediction technology from emergency earthquake early warnings as a method for estimating seismic intensity, we can create highly accurate indication of seismic intensity distribution in map form even if there are observation points where seismic intensity data is not available due to power outages etc, and it is now possible to provide.
2. Effectiveness of "Indication of seismic intensity distribution in map form"
Regarding the earthquake that occurred in the Noto region of Ishikawa Prefecture at around 16:10 on January 1, 2024, the indication of seismic intensity distribution in map form (IXAC41) was released approximately 10 minutes after the earthquake occurred. The indication of seismic intensity distribution in map form shows that almost the entire Noto Peninsula may experience a seismic intensity of 6 lower or higher, and wooden buildings with low earthquake resistance may collapse, and landslips and landslides may occur in these areas. We were able to grasp this possibility shortly after the earthquake occurred. In addition, there are three seismic intensity observation points that were announced in the earthquake information as "The seismic intensity is thought to be 5 lower or higher, but the seismic intensity is not currently available.", but we investigated the seismic intensity at these seismic intensity observation points that were later obtained. However, it was found that the estimated seismic intensity at these seismic intensity observation points almost matched the indication of seismic intensity distribution in map form released on the day of the earthquake. This shows that the indication of seismic intensity distribution in map form is effective as a tool for understanding seismic intensity in areas where seismic intensity data is not available due to obstacles or other reasons.
3. About the characteristics of shaking
We also investigated the characteristics of shaking at seismic intensity observation points. The earthquake that occurred in the Noto region of Ishikawa Prefecture at around 16:10 on January 1, 2024 caused tremors equivalent to seismic intensity 5 or higher in Wajimashi-Hugeshimachi (*3) and Suzushi-Misakimachi (*3). It was estimated that it took about 50 seconds. On the other hand, in the earthquake off the coast of the Noto Peninsula that occurred at around 23:20 on January 6, 2024, a seismic intensity of lower 6 was observed only at Shikamchi-Kano, and only a seismic intensity of 3 or lower was observed at other seismic intensity observation points. When we investigated the earthquake waveforms in Shikamchi-Kano, we found that the period of strong shaking was extremely short and had harmonic characteristics.
[Website of "Indication of seismic intensity distribution in map form" ]
URL: https://www.jma.go.jp/bosai/map.html#contents=estimated_intensity_map
*1 Seismic intensity meter installed by Ishikawa Prefecture
*2 K-NET observation point established by the National Research and Development Agency, National Research Institute for Earth Science and Disaster Prevention.
*3 Seismic intensity meter installed by the Japan Meteorological Agency
Acknowledgment
We used data from seismic intensity meters installed by each local government in the seismic intensity information network and data from the strong motion observation network maintained by the National Research and Development Agency, National Research Institute for Earth Science and Disaster Prevention.