Earthquake Journal Entry
Reno Rattled by Swarm of Quakes (May 5, 2008)
Bullseye shows epicenter of the largest of many quakes to hit the Reno area recently. USGS.
Nevadans living in Reno and towns near it are feeling a bit jumpy these days, with good reason. Since the end of February, the area's been hit by more than 1,000 earthquakes.
The series of quakes started on February 28th. Since then, aftershocks have rattled the area nearly nonstop. Most have been too small to be felt. But last weekend, a quake of magnitude 4.7 struck. It was the strongest one yet, knocking over furniture and cracking walls.
The epicenter of that quake was six miles (nine km) west of Reno. The shallow quake struck less than a mile (1.4 km) below the surface, according to the U.S. Geological Survey (USGS). Scientists say quakes that shallow are unusual for Nevada and California, where most strike at a depth of 3 to 5 miles (6 to 10 km).
The way the quakes are progressing is also puzzling. Normally, a larger quake is followed by smaller aftershocks. Eventually, the energy peters out. The Reno swarm doesn't fit the pattern. For example, a quake of magnitude 3.3 struck before last week's magnitude 4.7 quake.
After California and Alaska, Nevada is the third most earthquake-prone state in the nation. The last major quake to hit Reno was nearly a century ago, in April 1914. it registered magnitude 6.1.
