[S-CG53] Reducing risks from earthquakes, tsunamis & volcanoes: new applications of realtime geophysical data

[SCG53-01] Learning from Earthquakes: Characterizing Shaking and EEW Efficacy via Systematic Surveys

★Invited Papers

*David J Wald¹, Vince Quitoriano¹, James D Goltz², Masumi Yamada² (1.U.S. Geological Survey, National Earthquake Information Center, 2.Kyoto University, Disaster Prevention Research Institute)

Keywords:earthquake early warning, earthquake response, macroseismic intensity, earthquake shaking

The Japan Meteorological Agency (JMA) Earthquake Early Warning (EEW) system is not only the most sophisticated in the world, it is also the most activated due to the high rate of potentially damaging earthquakes in the region. As such, would-be information and lessons gained from post-event data collection could be the most comprehensive and useful for applications worldwide. JMA continues to gather valuable post-earthquake information from the public for select damaging earthquakes via event-specific surveys of macroseismic effects and early warning perceptions and actions. These current procedures for data acquisition could benefit from more systematic approaches in parallel with similar U.S. Geological Survey (USGS) efforts. To capture data related to public attitudes and assessments regarding EEW alerts—including views of alert usefulness and preferences in future alerts—we recently developed a supplemental EEW questionnaire associated with the USGS “Did You Feel It?” (DYFI) system. Following any significant earthquake, the community now has an opportunity to provide immediate feedback both on the felt and damaging effects via DYFI as well as how they received, responded to, and perceived EEW alerts. These latter reports come in via a DYFI follow-up questionnaire (Goltz et al., 2023). Immediately after the recent August 2023 M5.1 earthquake near Ojai, California, the DYFI system received over 14,000 felt reports, of which 2,490 were by people who received (or expected to receive) an EEW alert prior to the onset of shaking at their locations. Many who received alerts provided feedback on various aspects of the alerts they received, which allow for analyses of the respondent’s situation upon receiving the alert, characteristics of the alert received, and perhaps, most importantly, how the recipient responded if the alert was received prior to feeling earthquake motion. We expect much greater participation for inevitable, more significant earthquakes. The new EEW questionnaire is generic and thus is not particular to the USGS ShakeAlert warnings; it can be used for any EEW warnings delivered worldwide. Also, a recent addition to the DYFI and EEW questionnaire is multilingual accessibility, including a Japanese language version. However, responses to DYFI for events in Japan are limited, so aiming for survey uniformity in both countries may be beneficial. For example, the M7.5 2024 Noto-Hanto earthquake resulted in highly useful responses, but the total numbers were lacking (393 people completed the DYFI questionnaire, of whom 67 responded to our new EEW supplemental questionnaire). We face another data gap: Post-earthquake surveys of professional EEW users (utilities, businesses, transportation, and other critical systems) must be done more systematically in the U.S. and Japan. The USGS EEW follow-up questionnaire can be readily adapted for this purpose. Uniformity of post-event macroseismic assignments and EEW follow-up questionnaires of casual and professional users would be a boon to educational and scientific efforts related to EEW. Long-term U.S. and Japanese collaboration on the macroseismic and EEW surveys may pay significant seismological and social science dividends. Such routine participation could engender more public appreciation and facilitate better-informed societal uses of EEW information, allowing our populations to adapt more successfully to EEW alerts and to better prepare for and respond to earthquakes.

Goltz JD, Wald DJ, McBride SK, DeGroot R, Breeden JK, Bostrom A (2023). Development of a companion questionnaire for “Did You Feel It?”: Assessing response in earthquakes where an earthquake early warning may have been received, Earthquake Spectra, 39, 434-453.