Oregon's Earthquake Swarm

December 9, 2021 5:12 PM

More than 85 earthquakes have occurred along the Blanco Fault, off the coast of Oregon, since Tuesday. Before this swarm, there had been relatively little activity. Experts say these earthquakes, which are part of a slip fault, are in no way connected to the Cascadia Subduction Zone fault, which is much closer and shallower.

But, haven't quakes in different places in the past, relieved or increased pressure at non adjacent fault zones around the Earth, causing earthquakes at those locations? When I think of the Earth's plates, I think of a puzzle on a table and how all pieces are connected. Or is it not like that at all? IOW, is there, as the seismologists say, there is nothing to worry about?

posted by CollectiveMind to Science & Nature (2 answers total)

What seismologists along the US West Coast usually actually officially say IME is that the latest shake is no reason to increase our expectations of other seismic activity. But they think our current expectations should be very high.

The next sentence is something like "a big earthquake would be so not-surprising at any moment that small earthquake activity doesn’t measurably change its chances".
posted by clew at 6:16 PM on December 9, 2021 [2 favorites]

Yup, the current probability sits at a 37% chance within the next 50 years of a 7.1+ quake. Thats functionally imminent on a geologic timeframe. Not many geologic phenomenon get such a high and narrow probability in a certain time window.
posted by furnace.heart at 6:41 PM on December 9, 2021 [2 favorites]