Japan's government on Wednesday unveiled a worst-case disaster scenario that warned a monster earthquake in the Pacific Ocean could kill over 320,000 people, dwarfing last year's quake-tsunami disaster.
Tokyo's casualty toll estimate was based on a catastrophic scenario in which a powerful undersea quake of about 9.0 magnitude sparked a giant tsunami that swamps Japan's coastline south of Tokyo.
The Cabinet Office's hypothetical disaster would see the quake strike at night-time during the winter with strong winds helping unleash waves that reach 34-metre (110 feet), sweeping many victims away as they slept.
Many of the estimated 323,000 victims would be drowned by the tsunami, crushed under falling objects or in fires sparked by the disaster, it said.
Read More: Japan Estimates Monster Quake Could Kill 320,000