Image reproduced from 工商時報

Kagoshima Prefecture’s Tokara Islands in Japan has experienced over 1,100 felt earthquakes in the past two weeks, prompting local authorities to evacuate residents on July 4, ferrying them to Kagoshima City in Kyushu. The recent surge in seismic activity has led the central government to intervene, and experts from the Earthquake Investigation Committee held a press conference on the evening of the 4th, stating that preparations should be made for potential magnitude 6 tremors.

According to NHK, the Earthquake Investigation Committee, affiliated with the Ministry of Education, Culture, Sports, Science and Technology, reported that the recent seismic activities occurred within continental plates, with a total of 1,201 felt earthquakes of magnitude 1 and above recorded by 4 PM on the 4th, and the active seismic activity continues. Experts noted that while this region has a history of frequent quakes, this wave represents the most intense activity since 1995.

The committee emphasized that the area from Akuseki Island to Yokoate Island (both part of the Tokara Islands) lies along an extension of a volcanic chain, and past experiences indicate a likelihood of successive earthquakes of comparable magnitude. Committee Chair Naoto Hirata, a professor emeritus at the University of Tokyo, stated, “It is unclear what forces have triggered this series of earthquakes, and there are various opinions circulating, but the committee does not yet understand the cause.”
Hirata also offered his perspective, stating, “I personally believe that there is an active volcano north of Akuseki Island, where magmatic activity is happening beneath the surface, and this fluid movement increases the likelihood of earthquakes.” He cautioned that, regarding when this seismic wave would cease, “Strictly speaking, we do not know.” He pointed out, “However, it is clear that these earthquakes will not conclude in three days or a week. Unfortunately, I believe we must observe for a while longer to determine whether this wave of earthquakes has truly ended. Some cases, such as the activity in December 2021, calmed down for a while but became active again, so I urge everyone to be fully prepared.”

As for whether the recent eruption of Shinmoedake volcano at the border of Kagoshima and Miyazaki Prefectures is related to the Tokara Islands earthquakes, Hirata stated, “Scientifically, there is no correlation between the two. Unfortunately, earthquakes can occur at any time in Japan, and the likelihood of continued seismic activity in the waters around the Tokara Islands is very high; the Nankai Trough may also experience seismic events, so we must remain prepared for earthquakes.” On July 2, the Japan Meteorological Agency also cautioned the public to prepare for quakes of magnitude 5 or higher.