A Japanese expert estimates as many as 76,000 people would die from after-effects of a massive earthquake in the Nankai Trough along Japan's Pacific Coast.

There is a 70 to 80 percent chance a magnitude 8 to 9 earthquake will strike the trough in the next 30 years. The estimate assumes 9.5 million people in Japan would evacuate in the mega-quake striking the area.

Directly caused deaths is estimated to be about 323,000 in the worst case scenario. Injuries would be expected to total 623,000.

Professor Okumura Yoshihiro at Kansai University told NHK that evacuations and deteriorating health conditions could significantly increase total fatalities in the mega-quake.

Okumura, who specializes in the natural disaster case studies, looked at possible links between numbers of evacuees in previous disasters and numbers of those that died from after-effects.

The professor said extended power and water outages would contribute to deaths not directly caused by the quake itself. He also cited limited access to medical services as a cause.

Okumura emphasized that Japanese society as a whole should address the issue of foreseeable disaster-related deaths.

Fatalities related to Japan's March 2011 earthquake and tsunami but not directly caused by them stood at 3,789 as of the end of March last year.