TOKYO -- A record 740 earthquakes have been recorded off the coast of the Tokara island chain in southwest Japan's Kagoshima Prefecture in the last 10 days, the weather agency announced July 1.

According to the Japan Meteorological Agency's Fukuoka Regional Headquarters, there were 740 tremors measuring 1 or higher on the 7-point Japanese seismic intensity scale. While there have been earthquakes in the past with hundreds of tremors occurring over a period of two to three weeks, this is the largest number of quakes off the remote islands.

Seismic activity in the area intensified around 8 a.m. on June 21. By 11 a.m. on July 1, there had been one quake measuring lower 5 on the intensity scale, 11 measuring level 4, 44 with level 3, 185 registering scale 2 and 499 measuring 1. No tsunami have been observed, and there have been no reports of damage.

The waters surrounding the Tokara Islands -- a group of 12 islets located between Yakushima and Amami Oshima islands -- have experienced clusters of earthquakes every few years, but the weather agency's Fukuoka Regional Headquarters notes that this is the most active period in recent years.

The number of daily temblors peaked at 183 on June 23, then declined to 15 on June 26 and 16 on June 27, but rose again to 34 on June 28 and 98 on June 29. On June 30, 62 quakes were recorded.

Earthquakes with a seismic intensity of lower 5 and 4 were observed on Akuseki Island, which is home to 43 households and 89 residents.

According to Hisayoshi Yokose, associate professor of marine volcanology at Kumamoto University's graduate school, the area around the Tokara Islands features unique topography, including large underwater ridges that sink beneath a plate. This makes it easier for strain to build up, which is thought to lead to frequent earthquakes.

The weather agency is calling for caution, warning that quakes measuring around lower 5 may hit the area.

(Japanese original by Kazuki Mogami, Tokyo City News Department)