Mount Usu: A Volcano That Never Lies
Mount Usu stands out even in a national park full of volcanoes—it has the distinction of being one of the most active volcanoes in Japan. Formed fairly recently (almost 20,000 years ago), it was active for a period of time and then fell quiet for roughly 7,000 years. It awoke from its slumber in 1663 and has been keeping local residents alert for the past three and a half centuries. Usu has erupted eight times since 1663, with four of those events occurring within the past one hundred years (1910, 1944, 1977, and 2000).
To outside observers, this might seem frightening, but locals now find it reassuring—Mount Usu is becoming more regular, performing on a schedule of roughly every 30 years. Moreover, Usu usually warns residents that it is about to wake from a nap, with repeated earthquakes and ground ruptures taking place anywhere from a few days to several weeks before an eruption. This is one main reason why researchers are so interested in Mount Usu: it is regular, predictable, and polite enough to give advance warning before making a mess of the surrounding countryside. Hence, the common expression that Usu is “a volcano that never lies.”
The frequency of the mountain’s eruptions and the near certainty of more to come has made this area one of the world’s most advanced in terms of disaster preparation and local crisis management. Surrounding towns have refined hazard maps that show the direction and extent of possible damage, and they have developed emergency evacuation plans whose efficacy has been tested by the mountain on multiple occasions. In times of emergency, local railway companies even run special trains to help evacuate residents. In the year 2000, the mountain’s most recent eruption, 16,000 people were quickly moved to safety, resulting in no loss of life.
