Earthquakes that cannot be felt are being recorded in record numbers just south of Seattle, Washington. Quakes 20 miles below our feet are slowly releasing, and have been since early April.
For the first time since 2011, three distinct zones in the Pacific Northwest have been “going off” all at once. According to King 5 News, scientists say that the theory is that the sub-ducting ocean plate is being stretched like taffy in the heat that is the mantle of the earth. “Any signal you get is interesting,” said Tim Melbourne, a who runs the Northwest Geodetic Array, which is based at Central Washington University in Ellensburg.
“If you have something out in the dark, and you know it’s dangerous, you know it’s menacing, and every now and then you get a flash of light from it. Any flash of light doesn’t tell you a lot, but you piece them all together and you can start to put together all the angles, and you can start to see the dragon, and it’s a big dragon,” Melbourne said.
Melbourne’s metaphorical “dragon” is the Cascadia Subduction zone. Sections of the ocean floor are being pushed under the western edge of the North American continent creating pressure. Where the two plates join is a huge fault line, and the cooler upper portions of that fault are locked together. When they give way, typically between about 300 and 500 years, the result is a massive tsunami-triggering earthquake. The one scientists expect to occur off of our coast is expected to be a magnitude nine. And some government agencies have already been preparing for the inevitable event.
Episodes of tremors and plate slippage have been affecting the Pacific Northwest about every 14 months since at least the 1990s. Shaking from these events typically aren’t felt and don’t mean an earthquake is imminent. However, researchers believe the slip events are building up the pressure at the fault, which will eventually lead to a long-predicted magnitude 9 earthquake.
Though it appears several slip events are occurring, the latest data doesn’t seem to indicate the “main” event or “the big one” has started north of Seattle. But it’s still a good idea to be prepared.