A recently completed study found that the berms of the liquefied natural gas terminal proposed for Coos Bay’s North Spit should be able to hold back the waves from a tsunami.

Prepared by the Center for Coastal Margin Observation & Prediction at Oregon Health & Science University, the report used newly developed earthquake scenarios. They were prepared by a team of geologists from the Department of Geology and Mineral Industries, Oregon State University and the Canadian Geological Survey. These scenarios were fed into a computer that created models of how wave action would affect the Coos Bay area.

The report, which is expected to be published within the next 10 days, was made possible by advances in computer technology and improvements in the understanding of earthquakes.

Even in the worst-case scenario, the report said, the waves would only reach an elevation of 22 feet on the 55-foot elevation berms.

“With the current suite of earthquake scenarios it is found that tsunami waves do not inundate portions of the site founded above the proposed tank containment berm elevation of 55 feet ... during such an event,” a draft report of the study said.

Jordan Cove Project Manager Bob Braddock said he got the idea for the study last summer, during Coos County land-use hearings for the LNG terminal. One of the speakers mentioned tsunami studies taking place at Cannon Beach, so Braddock looked into the work.

He learned that DOGAMI had run hundreds of tsunami models in the coastal community on Oregon’s North Coast. A second study, in Bandon, began this spring. Eventually, the studies will allow DOGAMI to redraw the entire state’s coastal map with regards to tsunami inundation zones, said George Priest, a geologist who led the Cannon Beach work.

But any such mapping for the Coos Bay site is years away. Priest doesn’t even know when the work will be finished since funding for the project isn’t guaranteed.

So Braddock went to OHSU, where the DOGAMI modeling was handled, and commissioned a team of scientists to take several earthquake scenarios and apply them to Coos Bay. They included one of the larger scenarios used in the DOGAMI mapping effort published in 2002, as well as two from its latest study.

The comprehensive study will consider a couple dozen scenarios, but OHSU used an 280-year earthquake and a 579-year earthquake to represent average and worst-case scenarios, for the Jordan Cove site.

In the worst-case scenario, the first wave arrives at the beach about 20 minutes after the earthquake. Five minutes later, it slams the LNG project site. The second and third waves arrive 55 and 72 minutes after the earthquake respectively.

Such a tsunami would reach the LNG site from two directions: crossing the dunes and flowing through the entrance of Coos Bay and up the shipping channel.

“The ‘dune wave’ reaches the site first due to the shorter traveling distance from the beach,” the report said. “Stacking of waves occurs as the two first waves collide in the shipping channel, resulting in the maximum inundation near the project site (about) 15 minutes after the arrival of the dune wave.”

Braddock said he sought the study because of questions about how far a tsunami would travel inland.

“Original data was vague about the runup,” he said.

The scientific community’s understanding of earthquakes and tsunami has improved greatly in recent years, especially following the 2004 Indian Ocean tsunami, Priest said. And computers are faster these days.

“For the older maps, we just didn’t have the resources to do many trials,” he said.

For the Cannon Beach study alone, there were more than 200 trials, Priest said.

There weren’t as many scenarios conducted for the Coos Bay site, and the report suggests the conclusions may differ from the more conclusive DOGAMI  study.

For now, “this is the best information out there,” Braddock said.

Yinglong Joseph Zhang, an assistant professor at OHSU who helped with the hydrodynamic wave modeling, said the Coos Bay work should help DOGAMI as it explores Bandon.

“I see a lot of synergy between the two projects,” he said. “You want to test with as many scenarios as possible to see how good they are.”

Although Jordan Cove funded the research, he said it did not influence his work.

“I’m a scientist. My interest is not political,” he said. “If we did something wrong or dishonest, we will be criticized by our peers.”