Portland’s earthquake on Sunday was a 3.3-magnitude earthquake that was felt throughout the Portland area around 8:30 p.m. While there were no major damages or injuries after the quake, it was a wake-up call for Oregon residents to be prepared for a much bigger earthquake along the Cascadia subduction zone. According to an April 7 KGW News Channel 8 Portland report, “people should review their earthquake response plans and double-check their disaster kits.”
On Sunday night, a 1.6-magnitude earthquake was registered in the same area where the 3.3 quake struck just 10 minutes later. USGS reports that the epicenter of the 3.3-magnitude quake was about six miles north of Sherwood, at a depth of 12 miles.
Dr. Scott Burns with Portland State University's Department of Geology commented that the area where the earthquake took place in Oregon is an area “where we don't really have a fault mapped, a major fault, so maybe this is going to be a new one that we didn't know was actually there.”
"This is a good type of earthquake to have mainly because it was a 3.3; at least, that's the calculation right now. That's an earthquake that people are going to feel in the immediate area, but there's not going to be any damage. And that's just a reminder that we are earthquake country that we are in, and each one of us needs to be prepared," said Burns.
Following Sunday night’s earthquake in Portland, KGW is recommending for Oregon residents to review the Red Cross Earthquake Safety Checklist and to keep a disaster kit at hand complete with the following items:
- Water—one gallon per person, per day (3-day supply for evacuation, 2-week supply for home)
- Food—non-perishable, easy-to-prepare items (3-day supply for evacuation, 2-week supply for home)
- Battery-powered or hand-crank radio (NOAA Weather Radio, if possible)
- Extra batteries
- First aid kit
- Medications (7-day supply) and medical items
- Multi-purpose tool
- Sanitation and personal hygiene items
- Copies of personal documents (medication list and pertinent medical information, proof of address, deed/lease to home, passports, birth certificates, insurance policies)
- Cell phone with chargers
- Family and emergency contact information
- Extra cash
- Emergency blanket
- Map(s) of the area
According to Oregon state geologist Vicki McConnell, “there's about a 30 percent chance of a magnitude 8 earthquake occurring along the Cascadia subduction zone in the next 50 years, and about a 15 percent chance of a magnitude 9 quake.”
The Cascadia Subduction Zone is a 1,000 Km (about 620 miles) long dipping fault that stretches from Northern Vancouver Island to Cape Mendocino in northern California. It is a very long sloping fault that separates the Juan de Fuca and North America plates. The Juan de Fuca thinner oceanic plate is moving toward (and eventually shoved underneath) the thicker continental North American plate while the continental North American Plate offshore of British Columbia, Washington and Oregon is moving in a general southwest direction, overriding the oceanic plate. The Cascadia Subduction Zone is where the two plates meet.
Sunday night’s two small Portland earthquakes “have been important reminders that the Pacific Northwest is earthquake territory,” stated Oregon state geologist Vicki McConnell, “which means we should be prepared for one to hit anytime.”