 According to the Lawrence Berkeley National Laboratory Earth Sciences division, seismicity was very low prior to the use of the Geyser steam field for geothermal energy, although this may have been the result of low seismic coverage of the area.Before 1969, there were no earthquakes above magnitude 2 recorded by the United States Geological Survey (USGS) in an approximately area around the Geysers.Studies have shown that injecting water into the Geysers field produces earthquakes from magnitude 0.5 to 3.0, although a 4.6 occurred in 1973 and magnitude four events increased thereafter.