PORT TOWNSEND — Regional earthquake and tsunami hazards will be outlined in a forum at Fort Worden State Park today.
The Port Townsend Marine Science Center’s Quimper Geo Group will sponsor the talk on earthquake and tsunami hazards in the Port Townsend area at the park’s USO building from 3 p.m. to 4:30 p.m.
The presentation is open to the public, with a $5 suggested donation. Admission is free for members of the Port Townsend Marine Science Center.
Featured speakers will be Brian Atwater, U.S. Geological Survey geologist and noted tsunami expert, and Ron Tognazzini, a retired civil, structural and earthquake engineer from Sequim.
Earlier this month, Atwater addressed forums in LaPush, Neah Bay, Port Angeles and Sequim.
The magnitude 9 quake that rocked Japan on March 11 happened in a continental plate boundary similar to the Cascadia Subduction Zone, which runs north and south in the Pacific Ocean about 75 miles offshore from LaPush.
A quake in the subduction zone happens, on average, every 500 years. Atwater’s research found that the last 500-year subduction zone quake happened Jan. 26, 1700, creating a tsunami that was probably 10 feet above the high-tide line.
Atwater said at the Port Angeles forum March 10 that when the next earthquake hits the Cascadia subduction zone off the coast of Washington state, Neah Bay residents will have a little more than a half-hour to get to higher ground, while Port Angeles residents will have about an hour and a half and Port Townsend residents about two and a half hours.
Tognazzini will present tsunami research performed by Marley Iredale, a former Sequim High School student who did research in Discovery Bay in 2008 and 2009 and found signs of nine tsunamis over the past 2,100 years.
Iredale is now attending college at Washington State University in Pullman, Tognazzini said, and could not present her research herself.
Her study, “Evaluating Tsunami Risk in Discovery Bay, Wash.,” was based on some 500 hours studying sand beds under Discovery Bay.
Her research suggests that tsunamis have hit Discovery Bay about twice as often as the 500-year tsunamis formed by the subduction zone earthquakes in the Cascadia Subduction zone.
