Basement structure beneath Langford Well Lake basin, Fort Irwin, California, based on inversion of gravity data

Abstract

Gravity data were used to study the basement structure of Langford Well Lake basin at the U.S. Army National Training Center, Fort Irwin, California. Figure 1 shows the location of the study area. During 1996 and 1999, 290 new gravity stations were measured. These data were merged with existing data to produce a depth-to-basement map, which, in turn was converted to a structure map of the basement surface below alluvial fill. This information can be used to help interpret water flow and reservoir capacity of the basin. In addition, gravity gradients were used to suggest locations of faults through or below alluvial fill. These gradients may be evidence for repositioning or extending mapped faults. The locations of gravity stations are shown in figure 2 plotted on a colored grid of topographic elevations generated from 30 m DEM's (Digital Elevation Models). As shown by figure 3, gravity data used in this study are sufficiently accurate to permit 1-mGal contour intervals. Much of the older regional data in this study area are of lesser quality although they were included because they sufficiently represent regional gravity.