Gasoline from the tank was brought to the sea surface by the tsunami and underground water released by the liquefaction and ignited 5 hours after the earthquake. The fire spread to nearby tanks and induced explosions that fed the fire, allowing it to continue for 12 days. The fire spread to nearby residential areas leaving 1407 people displaced. This fire is said to be the worst industrial complex fire in the country's history. At the time the cause of the fire was said to be caused by the liquefaction, but later research into large earthquakes revealed that long period ground motion also played a role. At the time of the fire, the new specially-designed fire truck for fighting chemical fires had not yet been deployed to Niigata City. A request was sent to the Fire and Disaster Management Agency and troops were dispatched from the Tokyo division. There was a danger of the fire spreading to an attached oxygen tank, but the troops from Tokyo managed to stop it from spreading to the tank, after a 20-hour battle. Showa bridge The collapse of the Showa bridge in Niigata has been analysed in detail. From eyewitness reports it appears that failure began 70 seconds after the start of the earthquake, suggesting that ground motion was not responsible. Movement of piles beneath the bridge piers due to lateral spreading caused by liquefaction, is regarded as the main cause of the failure. Characteristics Earthquake The earthquake had a magnitude of 7.6 on the moment magnitude scale, but the relatively deep focal depth of 34 km meant that the perceived intensities on the coast of Honshu were generally VIII (Severe) or less on the Mercalli intensity scale, on consolidated ground. The calculated focal mechanism indicates reverse faulting on a west-dipping fault trending N20°E. The rupture area was similar to the 1833 Shōnai earthquake, and partially overlapped it. Tsunami The first wave of the tsunami hit Niigata City approximately 15 minutes after the earthquake. It caused flooding damage on Sado Island, Awa Island, and as far away as the Oki Islands in Shimane Prefecture. The wave reached heights of 3 m at Ryōtsu Harbor, 4 m at Shiotani and near Iwafune Harbor, and between 1 and 2 m at Naoetsu. It was also reported that due to the run-up that occurs on sandy beaches the wave reached 6 m in some places. The first wave