Slope Base Study Site (PN1A)

Moorings off the Oregon Margin

The Northeast Pacific is one of the most biologically productive regions within the world's oceans

Deck load for Leg 3

The equipment and instruments to be deployed at Endurance Offshore and Slope Base during Leg 3 of VISIONS 14.

Photo Credit: Skip Denny, APL-UW

Slope Base Deep Profiler Float  2015

The top of the Deep Profiler mooring at the Slope Base site is marked by a large syntactic foam float. This was installed during Leg 2 of the NSF-OOI-UW Cabled Array VISIONS'15 expedition. Credit: NSF-OOI/UW/ISS; V15 - ROPOS Dive R1855.

Location: 44.6ºN  125.4ºW         Water Depth: 2906-2909 meters

The Slope Base study site (Primary Node PN1A) is located near the foot of the continental slope about 60 miles (100 km) west of Newport, Oregon. This site is just west of the Cascadia Subduction Zone, where mega-earthquakes have occurred, producing tsunamis that impacted both NW coastal commmunities, as well as those along the east coast of Japan. The last magnitude 9 earthquake occurred in 1700. Just to the east, is the steep, continental slope that may result in strong topographic forcing effects on ocean currents.

The coastal region of the Pacific Northwest is a classic wind-driven upwelling system where nutrient-rich deep waters rise to replace warmer surface waters. The result is a large increase in marine productivity that ranges from phytoplankton to fish to marine mammals. Near bottom fauna are periodically negatively impacted by flow of deep waters with very low oxygen concentrations (hypoxia events), and upwelling of corrosive, acidified waters onto the continental shelf.

Coupled with other Cabled and Endurance Array installations off the central Oregon coast, the Slope Base site provides a wide variety of opportunities for seismic and coastal studies, including cross-shelf and along-shelf variability.

Infrastructure and instruments at the Slope Base (PN1A) include: