the country's weather agency said Tuesday. The December 8 quake triggered tsunami waves of up to 70 centimetres (28 inches) and injured more than 40 people, but no major damage was reported, according to the Japan Meteorological Agency (JMA) and the Fire and Disaster Management Agency (FDMA).

In the wake of the tremor, JMA officials issued a rare advisory, warning of an elevated risk of a megaquake -- defined as magnitude 8.0 or larger tremor -- in the north of the country. Scientists say that after an earthquake of magnitude 7.0 or larger, there is a one percent chance of a megaquake within seven days, and the advisory urges people to prepare emergency bags should they need to evacuate quickly. JMA official Issei Suganuma told AFP Tuesday that the "special warning period for residents had expired at midnight". "But it doesn't mean that quakes will not happen again, so we'd like residents to remain vigilant," Suganuma added. The JMA said there was still a heightened risk of a megaquake occurring off the northern coast, but it would decline as time passes. (Bssnews)