The Japanese government’s earthquake investigation panel raised the probability of a Nankai Trough earthquake to 80 percent within the next 30 years.

The panel of experts said that as of January 1, the probability of a magnitude 8- to 9 class earthquake occurring within 30 years had risen to about 80 percent from the previous 70-to 80 percent. 

The probability of a megaquake occurring in the Japan Trench and the Chishima Trench also rose. The chances of an 8.6-class megaquake occurring off the coast of Tokachi is now 20 percent.

The panel said that the adjustment reflects the passage of time since the last big quake in the area and does not indicate a sudden increase in risk.