Major earthquakes simultaneously hitting areas in the Pacific off central to western Japan could kill as many as 28,300 people, a government panel of experts studying quake disasters said Wednesday.

The panel of the Central Disaster Prevention Council proposed that 21 prefectures expected to be affected by the Nankai and Tonankai quakes with epicenters off shore between Shizuoka Prefecture and Shikoku Island be designated as areas for promoting quake disaster prevention measures.

The panel said the approximately 500 municipalities within these prefectures, such as Tokyo, Osaka, Wakayama and Kochi, be included among the government's designated areas that must prepare for the Nankai and Tonankai earthquakes.