2012 Volume 10 Pages 113-121
Japan Meteorological Agency started the service of Earthquake Early Warning (EEW) to the public since October 1, 2007. The warning is widely broadcasted by TV, radio and mobile phone in the area whose JMA intensity is expected to be more than 4. In order to make the best use of the lead time before the arrival of strong tremors for reducing casualties, enhancing people's knowledge and capacity to take proper actions after the warning is essential.
There was a small earthquake in Fukushima Prefecture on September 29, 2010. The expected intensity in the Tokyo metropolitan area exceeded 4 and EEW was provided although observed intensity was less than 4. Recently, the percentage of the people who can get EEW by mobile phones is increasing. At this earthquake, a lot of people received the warning by mobile phone in the Tokyo metropolitan area and it became a good opportunity for making people familiar with EEW. After this, the off the Pacific coast of Tohoku Earthquake occurred on March 11, 2011 and numerous aftershocks continued. EEW was successfully provided in Tohoku area at the main shocks. On the other hand, in the Tokyo metropolitan area, EEW failed at the main shock but frequently announced at aftershocks. However, some of the warning at aftershocks failed to estimate intensity properly due to technical limitation.
In this paper, two questionnaire surveys were conducted to understand people's awareness of EEW. The first one was done after the earthquake in September 2010 for the people who received the warning by mobile phone. The second one was done after the earthquake in Tohoku region in March 2011. The change of their awareness was analyzed comparing both results. Their behavior after receiving the warning was also analyzed and suggestions for enhancing their capacity to take proper actions after EEW were obtained.
