GRANTS PASS, Ore. (AP) — The U.S. Army Corps of Engineers is halfway through studies of the threat posed by a major offshore earthquake to its 20 dams in Oregon and southern Washington.

Dam safety program manager Matt Craig said Monday the dams were all built before engineers knew about the dangers of a major quake in the Cascadia Subduction Zone. Though the dams were not built to meet that kind of a threat, the agency doesn’t expect any of them to fail to the point of losing their reservoirs. There could, be some damage, such as settling of the dam structure, cracks in concrete, and some seepage.