USGS-NOAA cruise maps Cascadia subduction zone to assess earthquake hazards

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From July 31 to August 23, a joint USGS-NOAA cruise mapped seafloor depths, texture, and gas seeps in the Cascadia subduction zone offshore of Washington, Oregon, and northern California.

A woman stands on the desk of a ship as it sails under a bridge, she is smiling and holding on to the railing.

USGS geophysicist Janet Watt on board NOAA ship Rainier as it sets sail from Newport Marina in Yaquina Bay, Oregon. Yaquina Bay Bridge is overhead.

From July 31 to August 23, a joint USGS-NOAA cruise mapped seafloor depths, texture, and gas seeps in the Cascadia subduction zone offshore of Washington, Oregon, and northern California. The largest earthquakes in the world occur within subduction zones along the giant fault between the down-going and overriding plates. Such earthquakes have potential to trigger large tsunamis by raising or lowering parts of the seafloor. During the cruise, scientists mapped a total of 6,452 square kilometers of seafloor. They identified new faults offsetting the seabed, possible mud volcanoes, and numerous seeps that highlight the region’s geologic activity. Results from this mapping and related efforts will provide key baseline information for assessing earthquake, tsunami, and landslide hazards and developing situational-awareness products, as part of USGS work on Reducing Risk where Tectonic Plates Collide.

 

View from the top deck of a ship on water, looking down on the bow with three people standing, with a bridge in the background.

Entering Yaquina Bay, Oregon aboard the NOAA ship Rainier, approaching the Yaquina Bay Bridge with Newport Marina off to the right in the distance.

A man controlling a computer mouse is sitting at a computer looking at a computer monitor.

USGS scientist Pete Dartnell processes multibeam data collected from off the Pacific Northwest coast on a research cruise aboard NOAA ship Rainier.