Great Hanshin earthquake were from Kobe. Among major cities, Kobe, with its population of 1.5 million, was the closest to the epicenter and hit by the strongest tremors. This was Japan's worst earthquake in the 20th century after the Great Kantō earthquake in 1923, which claimed more than 105,000 lives. Most of the largest earthquakes in Japan are caused by subduction of the Philippine Sea Plate or Pacific Plate, with mechanisms that involve either energy released within the subducting plate or the accumulation and sudden release of stress in the overlying plate. Earthquakes of these types are especially frequent in the coastal regions
Imperial Japanese Navy Air Service and the first one to be completed as from the keel up. In the 1920s, the larger percentage of aircraft that were initially acquired and inducted into service, were land based seaplanes whose main tasks were reconnaissance and anti-submarine patrols. The Japanese had drawn up plans for the formation of 17 squadrons of these aircraft, but budgetary constraints limited the units to eleven until 1931. Under the terms of the Washington Naval Treaty two incomplete capital ships were allowed to be rebuilt as carriers, for the Japanese; and . However, "Amagi" was damaged during the Great Kanto earthquake in 1923