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:
- Opinion: Half the road, full stop – Understanding pedestrian right-of-way
Doug Dahl explains how Washington’s law requires drivers to stop when a pedestrian is within one lane of their half of the road, not just when directly in front. - Opinion: What is the cost of a bridge?
John Ley argues the I-5 Bridge replacement’s soaring cost stems from costly extras like light rail, noting other states deliver larger, toll-free bridges for much less. - Letter: Vancouver Mayor Anne McEnerny-Ogle makes several serious and incorrect engineering statements
Bob Ortblad critiques engineering claims by Vancouver Mayor Anne McEnerny-Ogle, highlighting cost and safety advantages of an immersed tunnel for the I-5 crossing. - Washington’s studded tire deadline is March 31
Drivers must remove studded tires by March 31 or face a $137 fine, with WSDOT urging early action due to busy service centers and no planned deadline extension. - VIDEO: WA diesel hits record $6.53, crushing truckers and school budgets
With diesel nearing $6.53 per gallon in Washington, trucking businesses and school districts now confront sharply higher fuel expenses affecting budgets and workers.
