Japan rocked by 2,000-quake swarm as tropical cyclone threat intensifies

Japan’s Tokara Islands in Kagoshima Prefecture have been rattled by more than 2,000 earthquakes since June 21, marking the most intense seismic activity in the region in nearly three decades.

The ongoing earthquake swarm now coincides with the approach of a tropical cyclone, heightening the risk of landslides and debris flows on waterlogged slopes.

The Japan Meteorological Agency (JMA) reported on July 14 that seismic activity around the Tokara Islands in Kagoshima Prefecture, southwestern Japan, has remained frequent and intense. Since the start of the swarm, over 2,000 tremors of Shindo 1 or greater have been recorded.The Shindo scale measures the degree of ground shaking in Japan, ranging from 0 to 7. A notable event occurred late on July 13, when a quake near Toshima Village on Akusekijima Island registered a Shindo 4, strong enough to be felt while walking and to cause unsecured items to fall.

The strongest tremor so far struck on July 3, measuring Shindo 6 lower, severely disrupting balance and causing structural damage, including cracked roof tiles and shattered windows.Daily tallies have remained high, with 30 quakes recorded on July 12, 70 on July 13, and 21 as of July 14.

This year's swarm has surpassed previous clusters in 2021 and 2023, and is now the most significant series of quakes recorded in the region since 1995. Experts attribute the heightened intensity to the shallow depth of the earthquakes and their proximity to inhabited areas.

Compounding the danger, the region is now under threat from an approaching tropical cyclone. Heavy rainfall has saturated slopes and, when combined with ongoing tremors, sharply increases the risk of landslides and debris flows.

The JMA and local meteorological offices have issued advisories, urging residents to remain vigilant, avoid unstable terrain, and follow updates from official channels.

(2025/07/14-00:00)