A hundred years ago, Tokyo experienced a terrible event—the Great Kanto Earthquake. It hurt many people and changed the city a lot. Disaster Prevention Day reminds of this sad event. The government thinks there is a 70% chance of another big earthquake in the next 30 years.

In 1995, there was another big earthquake in Kobe. It hurt about 6,000 people and showed that even not-so-strong earthquakes can be very bad for cities. In 2011, the Tohoku earthquake was the strongest ever in Japan. Thanks to strong building rules, not many people got hurt in Tokyo, but it showed that there could still be problems. Tokyo does not get strong earthquakes often, which might make people feel too safe. Sometimes, the early-warning system gives false alarms, which can be scary. But these warnings are very important for safety. The biggest danger is not buildings falling down, but the risk of fires. Old buildings, made before strict rules in 1981, are more dangerous. The 100-year anniversary of the 1923 earthquake reminds everyone to check if people are ready for emergencies.