BANDON — Two earthquakes trembled off the coast of Bandon earlier this month, roughly one week apart.
According to the United States Geological Survey, the first was a magnitude 4.2 quake on Saturday, May 18 just 124 miles from Bandon at 12:43 p.m.
The second was a 4.0 quake on Saturday, May 25. It was 243 miles from Bandon at 3:53 p.m.
“When these earthquakes happen, people think ‘oh great, it’s letting off pressure for Cascadia, the big one,’” said Ron Metzger, geology professor at Southwestern Oregon Community College. “This is independent to that.”
The anticipated Cascadia subduction zone, expected to be at 9.2 magnitude when it goes off, is located 50 to 70 miles offshore. According to Metzger, these two quakes seen this month were on the Blanco Fracture Zone where seamounts, or underwater volcanos, are associated with them.
“They aren’t super threatening,” Metzger said. “These small earthquakes, from 3 to 4 magnitude and then the one last year at 6.2, those are relatively small and involve horizontal plate movement that isn’t displacing the water column. From a bigger coastal perspective, they aren’t a tsunami generator either.”
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Although this is the case, he said it is a reminder that the Cascadia quake is in the future, though no one knows when it may happen.
“Anything you can do, even in a step-by-step pattern, is important,” he said. “When people talk about Cascadia, they remember a couple reports that said everyone west of the I-5 is dead and that’s problematic because the majority will live. There will be loss of life and infrastructure issues, but the majority of folks will survive. If we don’t get that message out there, people will assume it is so catastrophic they won’t do anything.”
Not only that, but he pointed out that disaster preparedness is helpful for events outside of Cascadia, including the February storm that left much of Douglas County without power for days and forced others in Myrtle Point to evacuate due to flooding.
“Your supplies aren’t just for the earthquake,” Metzger said. “When you prepare for the major event, any minor issues in the interim you will be prepared for as well.”
Metzger suggested that the public collect non-perishable food items or emergency supplies whenever there is a small quake locally or a major disaster worldwide, like the recent 8.0 quake near Peru.
“If you do something every time, it would help you prepare,” he said. “To me, this is always a continuing reminder.”