Preliminary results from a study related to the subduction of the Juan De Fuca Plate beneath the North American Plate off the coast of Washington and British Columbia indicate that the potential mega-thrust earthquake could strike closer to the Seattle-Tacoma area than previously thought. I believe this project is the same one where I posted their press release about two years ago. According to the article, the average return period for these mega-thrust earthquakes is 400 to 500 years with a range between 300 and 800 and the estimated magnitude of around 9.0. The last mega-thrust earthquake along the Cascadia Subduction Zone was in January of 1700. Previously, scientists predicted the earthquake would be centered just off the coast, they now think it could be 30 miles or more inland, under the Olympic Peninsula to the west of the Seattle-Tacoma area. Source: Physorg.com via Geology.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.
The National Geodetic Data Center (NGDC) of NOAA has an online collection of photos of various geologic hazards. Many of the photos are from older sets of 35mm slides that have been digitized. They are free to use provided you credit the photographer and the NGDC as the source. The would be really useful for educators and for powerpoint presentations. The only drawback is that they are in TIF format and some of them could use some retouching. (Photo by University of Colorado, made available by NOAA/NGDC)