Clark County Today takes a look back at the likelihood of a major rip of the full Cascadia Subduction Zone that would trigger a magnitude 9.0 earthquake in the next 50 years
John Ley
for Clark County Today
The Great ShakeOut earthquake drill will take place on Thursday (Oct. 17) at 10:17 a.m. This is the time when the first shake is simulated, and participants should drop, cover, and hold on for at least 60 seconds. But locally, what are the odds of a major earthquake?
“Oregon is pretty boring,” says Harold Tobin, director of the PNW Seismic Network. He shared a video highlighting 40 years of earthquakes at the 2019 Pacific Northwest Earthquake Forum. Tobin noted most of the earthquakes have been in California, Washington, or offshore.
The biggest concern is a major rip of the full Cascadia Subduction Zone triggering a magnitude 9.0 earthquake in the range of 10-14 percent in the next 50 years. Put another way, there is an 86 to 90 percent chance an M9 earthquake will NOT happen in the next 50 years.
This is also relevant in the current Interstate Bridge Replacement Program (IBR) discussion for replacing the current two bridge structures. People should know the IRB is NOT designing the replacement bridge to the highest standard, which would best withstand an M9 or greater earthquake. They have previously reported they are not designing it to the 2,500-year standard; but a 500-year standard, which is the most commonly used standard for assessing seismic risk.
Read the following article Clark County Today published three years ago, regarding earthquakes here in the Pacific Northwest, as part of this year’s “Great Shakeout” event.
An additional article is about Oregon’s plans addressing seismic vulnerabilities to their transportation system.
Also read:
- Letter: ‘The current bridge plan hurts economic development on BOTH sides of the river’Sam Churchill from Hayden Island shares his concerns over the economic impact of the current I-5 Bridge replacement proposal on both sides of the river.
- Clark County Council pushes back on multiple IBR detailsAverage weekday vehicle trips data shows insights into Vancouver transportation trends amid the Interstate Bridge Replacement project.
- Paying 16 times more for tolls than gas taxesDrivers may pay up to 16 times more for I-5 tolls than gas taxes, sparking concerns over rising transportation costs in Washington state.
- Part-time shoulder lane now activated for State Route 14 travelersState Route 14’s new part-time shoulder lane, designed for smoother traffic flow, opens in Vancouver.
- Public invited to open house to learn about future improvements on SR 500 in Vancouver, Oct. 29WSDOT invites public input on future safety improvements for SR 500, including pedestrian and bicycle lanes, on Oct. 29 in Vancouver.