Fissure in the Mojave Desert

Fissure near Lucerne Lake along State Route 247 (visible in background), Mojave Desert, California. The localized subsidence in five areas near dry lake beds was caused by declining water levels in fine-grained (clay and silt) sediments. In the Mojave River and Morongo Groundwater Basins (fig. 2), the combination of variable climatic conditions, tectonic activity, and other factors resulted in complex depositional patterns of clay in the subsurface, which, combined with water-level declines, define the lateral extent and magnitude of subsidence.