Yes there are. the local surface gravity at any spot on the Earth depends on the density of rock at that location. In regions where iron ore is abundant, the local gravity field would be slightly stronger than in regions with large deposits of sandstone or other comparatively lower density silicates. As a satellite orbits the Earth, its orbit can dip by several meters in response to the changing composition of the Earth along the line from the Earth's center to where the satellite is in its orbit at any moment. The above gravity anomaly map was created by the USGS for the Fort Irwin area. Here is the caption:
Rocks also have variable densities. For example, a volume of unconsolidated sedimentary deposits has less mass andproduces a smaller gravitational attraction than the same volume of limestone or dolomite. Sedimentary basins, therefore, are often reflected in the earth's gravity field as regions of relatively low gravitational attraction. These highs and lows are very small, on the order of 0.001 percent of the earth's gravity field. By measuring the earth's gravitational attraction at many points above the ground, we can produce maps of these "gravity anomalies" and thereby learn about the distribution of rocks below the ground. This map shows the regional gravity at Fort Irwin and surrounding areas. The dashed lines outline deep sedimentary basins (thicker than 500 meters deep) predicted to exist on the basis of these gravity measurements and geologic mapping. The three hatched areas, on the other hand, indicate actual basins at Fort Irwin. Notice that none of the Fort Irwin basins are very deep. Indeed, there are no deep basins within 15 km of Fort Irwin, a factor that could affect future development of the military base.