Blanco Fracture Zone

The Blanco Fracture Zone or Blanco Fault Zone (BFZ) is a transform fault zone off the coast of the Pacific Northwest of the United States which runs between the Gorda Ridge to the south and the Juan de Fuca Ridge to the north. The principal feature of the Blanco zone is the Blanco Ridge, [citeweb|title=Recent tectonics of the Blanco Ridge, eastern blanco transform fault zone|url=http://www.springerlink.com/content/u867130803k712tw/|publisher="Springer Science+Business Media"|accessdate=2008-08-26] a right lateral-moving fault which also incorporates some compression, thus accounting for the uplift expressed in the ridge. The ridge is not an oceanic spreading center, despite its name, whereas the Juan de Fuca and Gorda Ridges to which it is connected are. Similarly confusing, the Blanco Fracture Zone is not technically a true fracture zone, but a transform fault zone.

eismic activity

In March and April 2008, a series or swarm of moderate earthquakes occurred both near and within the Blanco zone. The swarm began on March 30 when over 600 measurable tremors begain occurring north of the zone within the Juan de Fuca Plate. [citeweb|title=2008 Oregon Offshore Earthquakes|url=http://www.pmel.noaa.gov/vents/oregon-quakes.html|publisher="NOAA"|accessdate=2008-08-27] On April 22, activity moved to the Blanco fault zone itself, near its junction with the Gorda Ridge.

ee also

*Geology of the Pacific Northwest

References

External links

* [http://earthquake.usgs.gov/eqcenter/eqinthenews/2008/offshore_oregon/ USGS - Offshore Oregon Sequence]
* [http://oregonstate.edu/dept/ncs/newsarch/2008/Apr08/swarm.html Orgeon State University - Earthquake Swarm]
* [http://www.washington.edu/burkemuseum/geo_history_wa/Cascade%20Episode.htm Cascadia tectonic history]