https://mediaweb.kirotv.com/theme/images/placeholder-square.jpg

$siteCallLetter Atlanta

SLIDESHOW: Geologic illustrations explain the Cascadia subduction Close Gallery

SLIDESHOW: Geologic illustrations explain the Cascadia subduction

Toggle Photo Panel
  • Loading...
  • Loading...
  • Loading...
  • Loading...
  • Loading...
  • Loading...
  • Loading...
  • Loading...
  • Loading...
  • Loading...
  • Loading...
  • Loading...
1 of 12
  • Show Caption ( + )

    The Cascadia Subduction Zone off the coast of North America spans from northern California to southern British Columbia. This subduction zone can produce earthquakes as large as magnitude 9 and corresponding tsunamis. 

    Hide Caption ( - )
  • Show Caption ( + )

    This shows Cascadia earthquake sources. (Image: USGS)

    Hide Caption ( - )
  • Show Caption ( + )
    At the Cascadia subduction zone, the Juan de Fuca plate dives beneath North America (illustration: Oregon Department of Geology and Mineral Industries) Hide Caption ( - )
  • Show Caption ( + )

    The area of the Cascadia subduction zone -- and the aftershock zone. 

    Hide Caption ( - )
  • Show Caption ( + )
    This image shows Cascadia margin turbidite (a current of rapidly moving, sediment-laden water) canyons, channels and 1999-2002 core locations. Major canyon/channel systems are outlined in blue.  (Image: oregonstate.edu) Hide Caption ( - )
  • Show Caption ( + )
    This is a seismic line. It shows "the sediment on top of the Juan de Fuca plate is scraped off and folded and faulted in what is called the “accretionary wedge”, which is essentially a wrinkled up rug of rock. That is what we can see best in these preliminary images, but the deeper subducting plate should be more visible out once the experts work their processing magic." (Image: PNSNHide Caption ( - )
  • Show Caption ( + )
    Another rendering of the structure of the Cascadia subduction zone. (Image: USGS) Click here for more information.  Hide Caption ( - )
  • Show Caption ( + )

    This image of the Cascade Subduction Zone, shows the location of the trench, the downgoing slab, the active volcanoes and some major earthquakes. (Image: National park Service)

    Hide Caption ( - )
  • Show Caption ( + )
    This shows what is going on in the subduction zone. "The Juan de Fuca plate, composed of dense oceanic crust and is covered in layers of sediment that has hardened into rock, is running into the North American plate," PNSN wrote on its blog. "Where they collide, the denser Juan de Fuca plate dives under (“subducts”) and the locked interface between the two is the Cascadia fault  that breaks in magnitude 9-ish earthquakes every couple hundred years."  (Image: PNSN) Hide Caption ( - )
  • Show Caption ( + )
    This map shows the seismic lines PNSN shot overlain on the topography of the sea floor. "You can see the outline of Gray’s harbor and Long Beach Peninsula at right. to orient yourself. The black wiggly north-south-ish line at left indicates where the Juan de Fuca plate begins to subduct. The black lines show where we collected data to create 2D seismic images." (Image: NOAA) Hide Caption ( - )
  • Show Caption ( + )

    A map, courtesy of the Washington State Seismic Hazards Catalog, shows expected shaking intensity in Washington. The New Yorker writes the cooler colors indicate lighter shaking, the warmer ones greater intensity. Photo via the New Yorker. 

    Hide Caption ( - )
  • Show Caption ( + )
    A new interest has sparked for some in the northwest, after the New Yorker's terrifying article on how the "big one" with the potential of a 8.7 to 9 magnitude will devastate Seattle and everything west of Interstate 5.  In this slideshow, the Cascasdia Subduction Zone is explained in various images. Hide Caption ( - )