Analysis of 2011 Virginia Earthquake Suggests Seismic Risk: The large ground motions also triggered rock falls over an unexpectedly large area

Comments:  Uranium Mining should not be down in Virginia but the Chatham and Danville faults are near Coles Hill, area of proposed u mining!  Remember the following info from USGS, Made Man Earthquake: "earthquakes can be induced by impoundment of water in reservoirs, surface and underground mining"  Now Tech has the following info:  "URVA's seismometer went "off-scale" — the earthquake's shear wave caused more intense ground motion at the station's location in Richmond than the seismometer was designed for".  This article suggest the following:  The large ground motions also triggered rock falls over an unexpectedly large area. They were reported as far as 245 km away. Quakes this size shouldn’t trigger landslides more than 60 km away from its epicenter.

Analysis of 2011 Virginia Earthquake Suggests Seismic Risk

November 8, 2012 by Range

 

Last year, the surprise 5.8-magnitude earthquake that struck central Virginia was actually worse than previously thought. Detailed analyses of the ground motions triggered by the event indicate that Washington DC and other affected regions could be at higher risk of major ground movement.
The event triggered landslides over a wider area than any other recorded quake anywhere in the world. The earthquake was centered 130 km south-southwest of Washington DC, near Mineral, Virginia. The August 23, 2011 quake was the strongest to hit the eastern USA since 1897.

Damaged pinnacles of the National Cathedral in Washington DC after the 2011 Virginia Earthquake

The findings were reported by scientists of the US Geological Survey at the Geological Society of American’s annual meeting in Charlotte, North Carolina.

The area affected by the quake was about the same as a much larger 7.2 tremor that struck Baja, California in 2010 because of a variety of factors, including the age, type, temperature and density of the rocks underlying the eastern United States.

US cities on the eastern seaboard could be more affected by future earthquakes. A large fraction of the seismic energy was directed towards the northeast, where several major population centers are located.

This preferential concentration and amplification of seismic energy has been noted in other fault-ridden regions in the world, but hadn’t been measured in the eastern USA because it is rarely hit by severe earthquakes.

The large ground motions also triggered rock falls over an unexpectedly large area. They were reported as far as 245 km away. Quakes this size shouldn’t trigger landslides more than 60 km away from its epicenter.