A Japanese refinery experienced damage from the Miyagi-Ken-Oki earthquake whose epicentre was 100 km away (magnitude = 7.4, local horizontal acceleration of between 1/5 and 1/3 g). The most serious property damage, concentrated east of the refinery’s 160-ha site, primarily concerned three tanks with fixed roofs containing 23,000 m³ of Top Crude, produced as black crude from a topping unit. Subsequent to the breaks caused on the shell/bottom welds, 68,100 m³ of product were spilled into the retention basin common to the three tanks, having a total capacity of only 23,000 m³. The excess quantity then spread over the entire site and flowed outside the installation until reaching the port. The site’s spherical LPG tanks fitted with 10 legs reinforced by thick cross-braces remained intact. All of the refining units were fully inspected prior to restarting operations.