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History and Future of Tsunami Warning System: Toward Timely, Accurate and Reliable Systems

Description: 

Following the 1896 and 1933 Sanriku tsunamis, each caused thousands of casualties, Japan Meteorological Agency (JMA) started a tsunami warning system in 1941 for the Sanriku coast, and the near-field tsunami warning system covered the entire Japanese coast in 1950. The tsunami warning system for far-field tsunamis was established in 1962, following the 1960 Chilean tsunami. Since 1999, JMA adopts numerical simulation and its database to improve accuracy. Once the location and magnitude are determined in 3 to 5 minutes after an earthquake, the database is searched to predict tsunami coastal arrival times and heights. Following the 2022 tsunami from Tonga eruption, which started several hours earlier than the expected tsunami arrival time, JMA now announces arrival times of atmospheric pressure waves for large-scale volcanic eruptions in the world.

For timely and accurate issuance of a tsunami warning, seismic and/or geodetic observations are essential. The database search requires an accurate estimate of location and magnitude, including those for tsunami earthquakes. A reliable warning should be based on observations of tsunamis, i.e., sea level. Recent deployments of offshore bottom pressure gauges help to confirm tsunami generation and propagation and improve the reliability of the warning. JMA adopts the tFISH system, which inverts offshore tsunami waveforms to estimate the tsunami source then coastal heights. The Recent deployment of dense networks such as S-net or DONET makes it possible to issue a warning based on tsunami data assimilation, without estimating the tsunami source.

Session: The Future of Tsunami Science, Preparedness and Response

Type: Oral

Date: 4/19/2023

Presentation Time: 04:45 PM (local time)

Presenting Author: Kenji Satake

Student Presenter: No

Invited Presentation: 

Authors