The number of Japan's Self-Defense Forces assisting in the aftermath of the devastating earthquake on the island of Kyushu has increased to 4,600, Defense Minister Shinjiro Koizumi announced.

The 7.1-magnitude quake was one of the most powerful to hit Japan in recent years. On the Japanese intensity scale, which measures the degree of perceptibility of tremors at the surface rather than the energy released—like magnitude, it was rated at a maximum of 7.

According to preliminary information, 13 people were killed and dozens were injured because of the earthquake.

In addition, the natural disaster caused fires, damaged roads and bridges, collapsed numerous buildings, and power outages were reported in some areas.