Some Lake Mead seismic activity due to quarry blasts
Some of the events recorded on seismographs as earthquakes around or under Lake Mead, were likely blasts from quarries in the region. AZGS seismologist Lisa Linville confirmed this in discussions with colleagues at the Nevada Seismological Lab in Reno. Despite this, has there been increased activity around the lake during the past spring and summer, as the lake filled at a record rate due to snowpack melt and releases from Lake Powell upstream? That will require more detailed analysis.
The map at right was compiled by AZGS for a review of seismicity in the Hualapai Valley but it shows historical earthquakes around Lake Mead, 1852-2011.
The Las Vegas Sun has an excellent article discussing the situation.