Japan's Meteorological Agency plans to end its Nankai Trough megaquake advisory on Thursday evening. But officials are calling on people not to lower their guard.

The agency issued the advisory one week ago after a magnitude 7.1 quake struck off Miyazaki Prefecture in southern Japan, saying the risk of a megaquake hitting somewhere along the Nankai Trough is relatively higher.

The Nankai Trough quake is predicted to occur along the plate boundary between Suruga Bay in Shizuoka Prefecture and the Hyuganada Sea in Kyushu.

The agency said one in several hundred quakes measuring magnitude 7 and above are followed by another measuring magnitude 8 or above in a nearby area within a week. It added that the advisory did not mean that a massive quake will definitely occur during a certain period of time.

The advisory asked 707 municipalities in 29 prefectures -- extending from around Tokyo in the east to Okinawa in the south -- to renew their preparedness for a possible disaster.

Authorities say people should make sure furniture is as secure as possible and find out where the nearest evacuation sites are located.

Households with young children, seniors and people with disabilities are advised to consider evacuating voluntarily.

The advisory will come to an end at 5 p.m. on Thursday. But officials say the Nankai Trough remains under risk of a massive quake in the future. Experts believe there's a 70 to 80 percent chance the area will have a temblor of magnitude 8 to 9 within the next three decades.