To better convey a sense of alarm and urgency to evacuate, the Japan Meteorological Agency will issue "an enormous tsunami will likely follow" warning after earthquakes that measure greater than magnitude 8.0.
To better convey a sense of alarm and urgency to evacuate, the Japan Meteorological Agency will issue "an enormous tsunami will likely follow" warning after earthquakes that measure greater than magnitude 8.0.
The shift from its past warnings that gave specific figures for the anticipated height of tsunami-announced Aug. 8-comes after the agency was criticized for failing to prompt people to evacuate immediately after the Great East Japan Earthquake.
On March 11, many people in Fukushima and Iwate prefectures were late in fleeing in part due to the agency's initial warnings anticipating 3 meter tsunami for both prefectures, issued three minutes after the temblor. The warning for Miyagi Prefecture was 6 meters.
Some experts say that giving specific figures is not helpful in generating a sense of urgency because how to interpret numbers differs from one person to the next.
Most of the approximately 15,700 deaths from the March 11 disaster were caused by the enormous tsunami that followed the magnitude 9.0 earthquake.
The agency issued revised tsunami warnings-more than 10 meters for the three prefectures-44 minutes after the earthquake.
In response to criticism, the agency has been reassessing the way it issues alerts and released an interim report on Aug. 8. It will compile a final report by the middle of the next month after consulting with anti-disaster experts and organizations.
In the interim report, the agency said it will issue tsunami warnings if an earthquake is more powerful than magnitude 8.0. While the agency will predict heights of tsunami, it will not give specific figures for each of the affected areas.
The agency said it will work on strong language to drive home the urgency of evacuation in the event of an impending tsunami. One example is "tsunami comparable to the one that followed the Great East Japan Earthquake is imminent."
For second and subsequent warnings, the agency will provide figures for tsunami height as details of the size of an earthquake and tsunami become available.
If a tsunami is expected after an earthquake measuring between 6.5 to around 8.0, the agency will announce the predicted height, as it has in the past.
The agency will keep three categories of warnings based on the severity of tsunami, but it will reduce categories of tsunami height to five (1 meter, 2 meters, 4 meters, 8 meters and more than 8 meters) from eight to reflect the margin of error.