ON THE PACIFIC, Day 9: Tectonic plates and earthquakes

From June 25 to July 9, UO geophysicist Dean Livelybrooks and a team of national scientists on board the Atlantis research vessel will recover earthquake-monitoring equipment in the Pacific Ocean. Follow tweets and other activity at @uocas and #uoshiptrip. Visit explorationnow.org/atlantis to follow the action live. To read previous dispatches from the Atlantis, visit http://around.uoregon.edu/cascadia-initiative.

There’s never been an offshore earthquake research project the size of the Cascadia Initiative.

“Never in any ocean, ever,” Anne Trehu said. “It’s an ambitious project, in that respect.”

Trehu, a seismologist at Oregon State University and chief scientist for this trip along with the UO’s Dean Livelybrooks, explained the project to me July 3.

Over a four-year period, 70 seismometers are in use to measure vibrations in the ocean floor at approximately 140 sites off the coast, from Canadian waters to northern California.

The data will give scientists a much broader understanding of the tectonic plates under the ocean that shift and collide, causing earthquakes and tsunamis. Because the data collected during this project will be made available on the Internet within weeks, it will serve researchers around the world, Trehu said.

The findings will be especially relevant in the Pacific Northwest, which is due for a major offshore earthquake because the oceanic Juan de Fuca plate is diving beneath the North American continent from Vancouver Island to Cape Mendocino.

Earthquake activity can be affected by water that was trapped in the oceanic crust and sediments that are released as the oceanic plate descends beneath the continent, ultimately weakening faults and allowing them to slip. But water affects earthquake activity in ways that aren’t fully understood, and this project will shed light on that relationship, Trehu said.

A better understanding of plate dynamics will yield better assessments of what might happen in an earthquake off the coast. “The better we can anticipate, the better we can focus our resources on what’s important,” Trehu said – “things like building codes, public education, evacuation planning.”

Data from the project will also reveal Earth structure beneath the ocean basin at a scale not seen before.

But geologists won’t be the only ones who benefit from the Cascadia Initiative.

The seismometers are also measuring tidal behavior and picking up signals from sea animals including fin and blue whales. Biologists, for example, will be able to study whale movements during winter periods when observation is difficult.

“I don’t think we know all the uses that will be made with this data,” Trehu said. “There will be a lot of discoveries that we don’t anticipate.”

Trehu’s collaboration with Livelybrooks during the two-week research mission on Atlantis has already yielded one discovery: Beavers and Ducks get along just fine anywhere other than on the playing field.

 “Even when you put them on a boat in the middle of the Pacific,” Trehu laughed. “These are close quarters.”

- by Matt Cooper, UO Office of Strategic Communications