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[HDS10-01] Public Recognition and Problems of Uncertain Earthquake Information in Japan
In Japan, the disaster prevention system based on earthquake prediction for Tokai earthquakes was reviewed in 2017, and a highly uncertain "Temporary Information" for Nankai Trough earthquakes was introduced as pre-earthquake information. Furthermore, in 2022, a similar "Hokkaido and Sanriku Offshore Late-October Earthquake Advisory" began operating for earthquakes in the Kuril Islands Trench and the Japan Trench. Both advisories are not intended to predict earthquakes, and the "Guidelines" that stipulate the disaster-prevention measures to be taken only require reconfirmation of daily disaster-prevention measures and preparation for evacuation, except under special conditions. Furthermore, since it is impossible to make a scientific judgment based on observations, it has been decided in advance that the period in which the disaster preparedness system should be terminated should be limited to one week, based on the social acceptance limit.
As of February 2024, neither of the two reports has been issued to warn the public about subsequent major earthquakes. Since the chance of hitting the target for a specific earthquake above the M8 class only occurs once every few decades to a few hundred years, the chance of the information being released is not very large, even if one expects a considerable number of blanks.
Because of this situation, the very existence of these two types of information is not well known, making their publicity and dissemination a challenge (e.g., Cabinet Office, 2023). Therefore, we conducted an online questionnaire survey to determine the level of awareness of the information and the status of disaster preparedness at the citizen level. For the Nankai Trough earthquake contingency information, we conducted a survey in July 2023 and obtained responses from 3,200 people in eight prefectures: Tokyo, Shizuoka, Aichi, Osaka, Hiroshima, Tokushima, Kochi, and Miyazaki (Otani and Hayashi, 2024). For the Hokkaido/Sanriku-oki Late-September Earthquake Warning Information, a survey was conducted in November 2023, and responses were obtained from 1,800 people in six metropolitan areas in Hokkaido: Sapporo, Asahikawa, Hakodate, Tomakomai, Obihiro, and Kushiro.
The respondents were asked to rate their awareness of the information on a four-point scale (i.e., "I am familiar with the information, having checked it on the Internet, etc.," "I have heard what kind of information it is through TV program commentary, etc.," "I have heard about it but do not know what kind of information it is specifically," and "I do not know."), 15.1%, 29.5%, 33.8%, and 21.6%, respectively. For the Hokkaido/Sanriku offshore late-stage earthquake advisories, 9.9%, 17.8%, 30.2%, and 40.2% respectively. The sum of the top two was 44.6%, about half of the total for the Nankai Trough, but only 27.7%, less than 30% of the total for Hokkaido. No significant differences by prefecture or city were found in both types of information.
For both types of information, recommended disaster prevention measures after the information is released are limited to reconfirming daily preparations, but it is difficult to predict what citizens will do if the information is suddenly released when the existence of the information itself is not known. Careful explanation of the content of the information and repeated dissemination of the information are considered necessary to establish the recommended disaster prevention actions.
As of February 2024, neither of the two reports has been issued to warn the public about subsequent major earthquakes. Since the chance of hitting the target for a specific earthquake above the M8 class only occurs once every few decades to a few hundred years, the chance of the information being released is not very large, even if one expects a considerable number of blanks.
Because of this situation, the very existence of these two types of information is not well known, making their publicity and dissemination a challenge (e.g., Cabinet Office, 2023). Therefore, we conducted an online questionnaire survey to determine the level of awareness of the information and the status of disaster preparedness at the citizen level. For the Nankai Trough earthquake contingency information, we conducted a survey in July 2023 and obtained responses from 3,200 people in eight prefectures: Tokyo, Shizuoka, Aichi, Osaka, Hiroshima, Tokushima, Kochi, and Miyazaki (Otani and Hayashi, 2024). For the Hokkaido/Sanriku-oki Late-September Earthquake Warning Information, a survey was conducted in November 2023, and responses were obtained from 1,800 people in six metropolitan areas in Hokkaido: Sapporo, Asahikawa, Hakodate, Tomakomai, Obihiro, and Kushiro.
The respondents were asked to rate their awareness of the information on a four-point scale (i.e., "I am familiar with the information, having checked it on the Internet, etc.," "I have heard what kind of information it is through TV program commentary, etc.," "I have heard about it but do not know what kind of information it is specifically," and "I do not know."), 15.1%, 29.5%, 33.8%, and 21.6%, respectively. For the Hokkaido/Sanriku offshore late-stage earthquake advisories, 9.9%, 17.8%, 30.2%, and 40.2% respectively. The sum of the top two was 44.6%, about half of the total for the Nankai Trough, but only 27.7%, less than 30% of the total for Hokkaido. No significant differences by prefecture or city were found in both types of information.
For both types of information, recommended disaster prevention measures after the information is released are limited to reconfirming daily preparations, but it is difficult to predict what citizens will do if the information is suddenly released when the existence of the information itself is not known. Careful explanation of the content of the information and repeated dissemination of the information are considered necessary to establish the recommended disaster prevention actions.