Liquefaction and foundation failure of Chevron oil and gasoline tanks at Moss Landing, California

Liquefaction of gray, coarse‐ to medium‐grained, esturine sand during the October 17, 1989 Loma Prieta (Ms=7.1) earthquake led to foundation failures of oil and tanks at the Chevron Marine Station at Moss Landing located about 25 km south‐southeast of the epicenter. Differential settlement of the foundations resulted in 1° to 6° of the tanks towards one another and an associated 2° to 7° inclination of tank piping. In addition, sand was vented around the bases of the tanks that contained the most oil and adjacent cracks. Liquefaction and related ground failure was not restricted to the vicinity of the Chevron tanks but was a widespread phenomenon at Moss Landing. Analysis of geological and geotechnical data at sites such as the Chevron Marine Station will serve to check and to advance current methods of assessing liquefaction potential at a site and of mapping liquefaction hazard on a regional scale.