Japan tremors raise fears of overdue megaquake killing 199,000

The most recent quake, a magnitude 4.9 offshore tremor recorded on Sunday evening near Miyako in Iwate prefecture, was small and caused no reported damage.

Yet authorities are urging residents to remain vigilant and review their evacuation plans after a succession of smaller offshore quakes in recent days off Aomori and Fukushima prefectures, both within the wider Tohoku region.

The latest seismic swarm coincides with the release of an alarming update from the Central Disaster Management Council, which projects massive casualties and destruction should a “maximum-class” earthquake occur along two major ocean trenches off Japan’s northeast coast.

The Japan Trench, running parallel to Ibaraki, Fukushima and Miyagi prefectures, and the Chishima Trench, extending off Iwate, Aomori and Hokkaido, are each thought to produce cataclysmic quakes every 300 to 400 years.