Operational Earthquake Forecasting in Japan: A Study of Municipal Government Planning for an Earthquake Advisory or Warning in the Nankai Region

Abstract

Abstract A team of social scientists from the United States and Japan has conducted a study exploring the extent to which municipal governments in Japan have developed plans for response to an operational earthquake forecast from the Japan Meteorological Agency (JMA), indicating that seismic activity in the Nankai trough region has elevated the short-term probability that a major earthquake may occur. Employing both survey research and in-depth interviews, the team explored various aspects of the history and science behind the alerting system, guidance from the national government of Japan, and planning by local jurisdictions for a possible future Nankai trough major earthquake. The survey included questions regarding planning actions included in response plans for receipt of “special earthquake warning information” as well as questions regarding challenges in the planning process, expectations that an earthquake would follow the issuance of an alert, and whether planning would reduce the number of fatalities and injuries. We also conducted in-depth interviews that explored the scientific basis for the alerting system and asked working disaster managers in the Nankai region what they had done to plan and the reasons for not planning if plans had not been developed. We received 469 responses from a total of 736 jurisdictions that comprise the Nankai region—a response rate of 63.7%. We conducted a total of 17 in-depth interviews. In general, we found that a majority of jurisdictions have response plans for receipt of an alert from the JMA; however, the plans lacked a number of planning elements considered important from a disaster management perspective. In addition, many smaller jurisdictions lacked the staffing, resources, and guidance to form comprehensive response plans. Our report identifies both the strengths and weaknesses of existing plans, and outlines a program for improving planning in the region.