Abstract

The 1992 Truman Drive landslide in Santa Clara, Utah, began moving on May 2, 1992, and caused damage to backyard property, utility lines, and a chain-link fence, as well as partial blockage of Truman Drive, before stopping on May 21, 1992. The landslide occurred on the 24-m- (80-ft-) high south-facing bluff of the Santa Clara Bench where other historical landslides have occurred. The main factors contributing to the failure included: (1) the steep (about 50 percent) pre-failure slope of the bluff, (2) the presence of a relatively impermeable, weak, weathered shale which underlies most of the slope, (3) removal and steepening of parts of the slope during the widening of Truman Drive, and (4) water perched on the shale unit which saturated slope materials. Initial measures taken by Santa Clara City to stabilize the landslide included buttressing the toe of the landslide and construction of a drain trench along the left margin and head of the landslide to intercept and remove water from the landslide deposit.