5:15 PM - 6:45 PM
[U15-P44] Utilization of Earthquake Early Warnings for the earthquake (M7.6) with an epicenter in the Noto region of Ishikawa Prefecture that occurred at 16:10 on January 1, 2024
Keywords:Earthquake Early Warning, Utilization
[Introduction]
The Japan Meteorological Agency (JMA) issues Earthquake Early Warnings (EEWs) for the people in Japan. This is a system that issues prompt alerts just as an earthquake starts, providing valuable seconds for people to protect themselves before strong tremors arrive.
An earthquake with a magnitude of 7.6 occurred in the Noto region of Ishikawa Prefecture at 16:10 on January 1, 2024, and a maximum seismic intensity of 7 was recorded in Wajima City and Shiga Town, Ishikawa Prefecture. JMA issued an EEW for a total of 21 prefectures, including the Chubu region.
[Survey]
JMA surveyed the utilization of EEW for the recipients of that Warning. The questionnaire survey was conducted by posting a link to the questionnaire on the JMA website and asking respondents to respond online. When we called for responses through the JMA's Disaster Prevention Information X (formerly Twitter), we received 11,405 valid responses (including within the warning target area: 9,527).
[Result]
Approximately 60% of 9,527 respondents in warning target area replied, "I took some action'' when they received an EEW, and the most common behavior were “I prepared myself on the site”, “I tried to get earthquake information on TV, radio, mobile phones, etc” , and “I took care falling things”. Less than 20% of people responded they took no action when they received the EEW. The major reasons of no action were “the place I was at the time seemed safety or I had already moved to safe site,” and “I thought the shaking was not so strong.” Their behavior when they felt the shaking was similar to what they took some action when they received an EEW. When the shaking stopped, the most common behavior was “I tried to get earthquake information on TV, radio, or mobile phones,'' followed by “I checked on the safety of my family and friends”.
Also, when asked about their opinions and knowledge regarding EEWs, about 80% understood the mechanism and purpose of EEWs, but about 30% answered that there are two types of EEWs: warnings and forecasts. In terms of opinions regarding emergency EEWs, regarding whether they prioritize "promptness" or "accuracy" in EEWs, approximately 90% of 11,405 respondents prioritize “promptness”. Furthermore, from February 2023, prediction of long-period ground motion classes was added to the announcement standards for EEWs , but awareness tended to be low, with approximately 40% of respondents saying they were aware of it. Compared with past surveys, similar trends were observed in the questions asked for the May 5, 2023 earthquake in the Noto region of Ishikawa Prefecture (M6.5).
[Discussion]
Long-period ground motion class 2 was observed in the Kanto region, and it is thought that the shaking was large in high-rise buildings. It has been found that the addition of long-period ground motion classes to EEW predictions is not well-recognized, so further public awareness is needed in the future. The preliminary results of the questionnaire survey are available on the Japan Meteorological Agency website. In the future, we will conduct statistical processing of actions taken when they received an EEW for areas covered by warnings, but we will also conduct cross tabulations to see what actions were most common in each prefecture and in areas with high seismic intensity. We plan to analyze it in detail.
[WEB site] (Japanese)
https://www.data.jma.go.jp/eew/data/nc/shiryo/pre-survey/2024/20240101-ishikawa-brief.pdf
The Japan Meteorological Agency (JMA) issues Earthquake Early Warnings (EEWs) for the people in Japan. This is a system that issues prompt alerts just as an earthquake starts, providing valuable seconds for people to protect themselves before strong tremors arrive.
An earthquake with a magnitude of 7.6 occurred in the Noto region of Ishikawa Prefecture at 16:10 on January 1, 2024, and a maximum seismic intensity of 7 was recorded in Wajima City and Shiga Town, Ishikawa Prefecture. JMA issued an EEW for a total of 21 prefectures, including the Chubu region.
[Survey]
JMA surveyed the utilization of EEW for the recipients of that Warning. The questionnaire survey was conducted by posting a link to the questionnaire on the JMA website and asking respondents to respond online. When we called for responses through the JMA's Disaster Prevention Information X (formerly Twitter), we received 11,405 valid responses (including within the warning target area: 9,527).
[Result]
Approximately 60% of 9,527 respondents in warning target area replied, "I took some action'' when they received an EEW, and the most common behavior were “I prepared myself on the site”, “I tried to get earthquake information on TV, radio, mobile phones, etc” , and “I took care falling things”. Less than 20% of people responded they took no action when they received the EEW. The major reasons of no action were “the place I was at the time seemed safety or I had already moved to safe site,” and “I thought the shaking was not so strong.” Their behavior when they felt the shaking was similar to what they took some action when they received an EEW. When the shaking stopped, the most common behavior was “I tried to get earthquake information on TV, radio, or mobile phones,'' followed by “I checked on the safety of my family and friends”.
Also, when asked about their opinions and knowledge regarding EEWs, about 80% understood the mechanism and purpose of EEWs, but about 30% answered that there are two types of EEWs: warnings and forecasts. In terms of opinions regarding emergency EEWs, regarding whether they prioritize "promptness" or "accuracy" in EEWs, approximately 90% of 11,405 respondents prioritize “promptness”. Furthermore, from February 2023, prediction of long-period ground motion classes was added to the announcement standards for EEWs , but awareness tended to be low, with approximately 40% of respondents saying they were aware of it. Compared with past surveys, similar trends were observed in the questions asked for the May 5, 2023 earthquake in the Noto region of Ishikawa Prefecture (M6.5).
[Discussion]
Long-period ground motion class 2 was observed in the Kanto region, and it is thought that the shaking was large in high-rise buildings. It has been found that the addition of long-period ground motion classes to EEW predictions is not well-recognized, so further public awareness is needed in the future. The preliminary results of the questionnaire survey are available on the Japan Meteorological Agency website. In the future, we will conduct statistical processing of actions taken when they received an EEW for areas covered by warnings, but we will also conduct cross tabulations to see what actions were most common in each prefecture and in areas with high seismic intensity. We plan to analyze it in detail.
[WEB site] (Japanese)
https://www.data.jma.go.jp/eew/data/nc/shiryo/pre-survey/2024/20240101-ishikawa-brief.pdf