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.
General
Geologists Recover Pieces of San Andreas Fault from 2 Miles Deep
As a follow up to a previous post, the San Andreas Fault Observatory at Depth (SAFOD) team has announced that they have successfully completed their drilling and obtained cores of the San Andreas Fault at depths in excess of 2 miles below the surface. The zone of interest is approximately 135-ft in length. The core size is 4-in diameter. They have cemented in a 7-in casing and the next phase of the project will be to perforate the casing within the fault and install monitoring equipment consisting of seismometers, accelerometers, tiltmeters and a fluid pressure transducer. Read on for more info and links. (Image credit: EarthScope / NSF)
Weekend CUP
Weekend CUP for April 13, 2010
Subsidence Beneath a UK Sports Stadium | Geology.com Widespread landslides in Rio de Janeiro and Niteroi in Brazil – Dave’s Landslide Blog Contractor Cleared to Start Tunnel On Hetch Hetchy System Program – ENR: Engineering […]
Geologic Hazards
Christchurch liquefaction prone soils make rebuilding difficult |
This article notes that the combination of shallow water table and crummy soils make it difficult to rebuild safely in the Christchurch, New Zealand business district. Another interesting item mentioned in the article is that […]