Seismic signals chronicle deadly landslide

LANDSLIDE SHOCK A landslide on the North Fork of the Stillaguamish River outside Oso, Wash., on March 22 generated seismic waves like those unleashed during an earthquake.
Ted S. Warren/Associated Press
LANDSLIDE SHOCK A landslide on the North Fork of the Stillaguamish River outside Oso, Wash., on March 22 generated seismic waves like those unleashed during an earthquake.
Ted S. Warren/Associated Press