This rock fall is one of the largest natural landslides that occurred within the last few years. And this 68 MILLION ton rock fall has been located through seismic data gathered from around the world.
This landslide took place at Mount La Perouse in a remote area in southeastern Alaska on February 16 2014.
Here a before and after picture from NASA:
Debris from the landslide flowed 4.8 kilometers downhill and left deposits as deep as 40 feet-almost the height of a five-story building.
Large landslides in remote locations used to go unnoticed. A new remote sensing approach, based on seismic data, can reveal the time, force, direction, and speed of a large landslide. Unlike earthquakes, which release bursts of energy for a few seconds, landslides create sustained seismic readings that can last many minutes.
For more pictures and explanations follow this link here!