We're starting off the work week with a magnitude 1.9 earthquake just east of the Arizona-Nevada border near Lake Mead and Boulder City, at 7:29 AM local time today.
There have been a number of similar small events in the region in the past weeks and months, and a number clustered under Lake Mead itself, which we attribute to the rapid filling of the reservoir with Rocky Mountain runoff coming down the Colorado River. [right, location map from USGS]