The government announced an emergency response plan Tuesday that will see up to 140,000 Self-Defense Forces personnel, firefighters and police offers from around Japan dispatched to the Tokyo metropolitan area if a magnitude 7-class earthquake directly hits the capital.

The plan, revised from one drawn up in 2008, reflects potential damage estimates that were upgraded after the massive March 2011 offshore earthquake spawned tsunami that wrecked the Pacific coastline of Tohoku.

It lays out disaster response activities in chronological order for the first 72 hours after the quake, a period considered a crucial to finding survivors.

Emergency responders on call nationwide will include up to 110,000 SDF members, 16,000 firefighters and 14,000 police officers.

Key road and rail routes will be cleared for transporting personnel and supplies within 24 hours, and rivers may be used if land routes are unsuitable, according to the plan.

Regional disaster medical assistance teams, currently numbering about 1,400, will be dispatched immediately without waiting for requests from local authorities.

Local authorities and households will be expected to store enough food to support themselves for three days. Drinking water will be provided as necessary from trucks for the first seven days, while food and sanitary supplies will be dispatched to evacuation centers from the fourth day following the quake.

The plan calls for people who cannot safely return home to temporarily shelter at their workplaces and other designated places after the quake.

According to current government estimates, a magnitude 7.3 quake centered beneath southern Tokyo could in the worst case scenario see 23,000 people killed and 610,000 buildings destroyed, due to either the shaking or subsequent fires.