The Lituya Bay Tsunami hit the Gulf of Alaska more than 60 years ago. On July 9, 1958, an earthquake estimated at magnitude 7.7-8.3 triggered a massive landslide or rockslide here, estimated at 40 million cubic yards. The shape of the bay is long and narrow with glaciers entering it in two locations on the landward side, like the top of the letter T. The rockfall hit one of the glaciers and caused a Tsunami that ranup 1,720 feet on the nearest shore, with a wave height in the bay estimated at 50 to 75 feet high! Read more about the event from one of my favorite geo bloggers, David Bressan on Forbes.com.
From the USGS Newsroom:
USGS scientist Ken Hudnut fills us in on how science created the theoretical magnitude 7.8 earthquake behind the Great Southern California ShakeOut—the largest earthquake preparedness drill in U.S. history, coming Nov. 13—and what such an earthquake would do to downtown Los Angeles.
Seems like they did it right wiith this study. They had multiple teams independenlty come up with the ground shaking model, then had different structural engineers who are experts in seismic design of large buildings review the tall buildings in the L.A. area for the design earthquake. They say that buildings would likely come down in the 7.8 magnitude event. Click through to watch the video interview from the USGS.
A massive rockslide closed a busy interstate route last week near the border between Tennessee and North Carolina in Pigeon River Gorge. This area has had landslide problems in the past. In 1997 a rockslide in the same area closed the freeway for approximately 3 months. (Photo from Landslides Under a Microscope Blog, original source not cited)
I have yet to see volume estimates, but The Charlotte Observer quoted a highway patrol officer who was at the scene:
He said the roadway is covered by a gigantic mound of debris, from pebbles up to house-sized boulders. The pile is 40 to 50 feet high, Williamson estimated, and hundreds of feet long.
More info and video after the break. […]