Mojave Land-Subsidence Studies

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Land subsidence has been ongoing in the dry lake beds throughout the Mojave and Morongo groundwater basins since the 1960s. In a study conducted from 2004 - 2009, continuous GPS stations were added to interferometric synthetic aperture radar (InSAR) methods to measure changes in land surface altitude.

long fissure in the dry Mojave Desert with the mountains in the background

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. (Credit: Michelle Sneed, USGS. Public domain.)

Spatially detailed maps of interferometric synthetic aperture radar (InSAR) methods were used to characterize land subsidence associated with groundwater-level declines during various intervals of time between 1992 and 1999 in the Mojave River and Morongo groundwater basins (Sneed and others, 2003). Concerns related to the potential for new or renewed land subsidence in the basins resulted in a cooperative study between the Mojave Water Agency (MWA) and the U.S. Geological Survey (USGS) in 2006. InSAR data were developed to determine the location, extent, and magnitude of vertical land-surface changes in the Mojave River and Morongo ground-water basins for time intervals ranging from about 35 days to 14 months between 1999 and 2000 and between 2003 and 2004. Continued analysis of InSAR data, coupled with geologic and hydrogeologic data, to determine the location, extent, and magnitude of vertical land-surface changes in the Mojave River and Morongo groundwater basins is presented from 2004 to 2009. The results from many future land-subsidence studies, which are scheduled about every 10 years, will be available on  the Mojave Water Resources Interactive Map.

For more information, please visit the Mojave Land-Subsidence Studies site.