For a length of about 1,800 feet, the embankment (including the parapet wall, dam crest, most of the upstream slope, and a portion of the downstream slope) slid into the reservoir. A loss of about 30 feet of dam height resulted when as much as 800,000 cubic yards of dam embankment was displaced into the reservoir. This material slid when liquefaction of the hydraulic fill on the upstream side of the embankment occurred. The dam was about half full at the time. Eighty-thousand people living downstream of the dam were immediately ordered to evacuate, and steps were taken to lower the water level in the reservoir as rapidly as possible. The Los Angeles Dam was constructed to replace the Van Norman Reservoir. In the 1994 earthquake, some ground movement with minor cracking seems to have occurred at the site. There was significant differential settlement of the ground of about two inches in the northern section, and eight inches in the southwestern section of the site.

Image Credit: E.V. Leyendecker. U.S. Geological Survey