Cascadia subduction zone
The Cascadia Subduction Zone (also known as the Cascadia Fault ) is the converging plate boundary between the Juan de Fuca Plate and the North American Plate . It extends about 1,100 km off the west coast of Canada and the USA between the northern end of Vancouver Island and the northernmost part of California . As part of the Pacific Ring of Fire , it is responsible for the activity of the Cascade Volcanoes . The Cascadia subduction zone merges to the north into the Queen Charlotte transform fault and to the south into the San Andreas transform fault . It forms the remainder of a previously much wider subduction zone that separated the Farallon Plate from the North American Plate.
earthquake
The calculated average period between major earthquakes is 200 to 220 years, based on data from the last 3000 years.
The 1700 Cascadian earthquake reached a magnitude of 8.7 to 9.2 on the Richter scale and resulted in a tsunami in Japan. Crater Lake was formed about 7,500 years ago, and Mount Meager erupted 2,350 years ago . More recently, the 1980 eruption of Mount St. Helens became known to a wide public.
Link to the San Andreas Fault
The San Andreas fault activities are related to the Cascadia subduction zone. Their seismic activities often precede the earthquakes of the San Andreas fault, on average 25 to 45 years. In a study with turbidites , 15 earthquakes in the San Andreas Fault found 13 quakes in the Cascadia zone that occurred simultaneously.
literature
- Jerry Thompson: Cascadia's Fault: The Coming Earthquake and Tsunami that Could Devastate North America. Counterpoint , Berkeley 2011, ISBN 978-1-58243-824-5 .
Web links
- Kathryn Schulz: The Really Big One - An earthquake will destroy a sizable portion of the coastal Northwest. The question is when. The New Yorker website, July 20, 2015.
Individual evidence
- ^ A b Seismological Society of America : Earthquakes Along The Cascadia And San Andreas Faults May Be Linked, Affecting Risk To San Francisco Bay Region. ScienceDaily , April 8, 2008, accessed July 29, 2015.
- ^ Kathryn Schulz: The Really Big One - An earthquake will destroy a sizable portion of the coastal Northwest. The question is when. The New Yorker Website, July 20, 2015, accessed July 29, 2015.