The U.S. then constructed airfields on Saipan and Tinian where B-29s were based to conduct strategic bombing missions against the Japanese mainland until the end of World War II , including the nuclear attacks on Hiroshima and Nagasaki .

The planned Arranging operation Military_operation was canceled Change_event_time when Japan surrendered Surrendering following the atomic bombings Attack of Hiroshima and Nagasaki , the Soviet declaration of war Hostile_encounter and the invasion Attack of Manchuria .

In both cities , most of the dead Death were civilians , although Hiroshima had a sizable military garrison .

On August 6 , one of the modified Change B-29s dropped Motion_directional a uranium gun-type bomb ( `` Little Boy '' ) on Hiroshima .

The war culminated Process_end in the atomic bombings of Hiroshima and Nagasaki , and other large aerial bomb attacks Attack by the Allies , accompanied GetReady by the Soviet Union 's declaration Expressing_publicly of war and invasion Attack of Manchuria and other territories on 9 August 1945 , resulting in Causation the Japanese announcement Expressing_publicly of intent to surrender Surrendering on 15 August 1945 .

During early August 1945 , the cities of Hiroshima and Nagasaki were struck Attack and mostly destroyed Destroying by atomic bombs .

The energy released by the quake Catastrophe was equivalent to 32 of the bombs dropped in Hiroshima .

The bulk of the object 's energy was absorbed by the atmosphere , with a total kinetic energy before atmospheric impact Influence estimated from infrasound and seismic measurements to be equivalent to the blast yield of 400–500 kilotons of TNT ( about 1.4–1.8 PJ ) range – 26 to 33 times as much energy as that released Causation from the atomic bomb detonated Attack at Hiroshima .

Despite continuing to occupy part of China 's territory , Japan eventually surrendered Surrendering on September 2 , 1945 , to Allied forces following the atomic bombings Attack of Hiroshima and Nagasaki and the Soviet invasion Attack of Japanese-held Manchuria .