Wednesday, 22nd May 2019 16:40

Do Tremor Bursts Indicate Imminent 9.0 Quake?

A recent spate of earthquakes dating back to as early as April 2019 and numbering in the dozens have been going off and the average person has no idea.

Not only has this tectonic activity been going on as deep as 20 miles below the surface, we now know that they signify an event that has not been experienced since 2011; three separate tectonic zones all moving at the same time.

The most recent event in this tectonic "swarming" happened beneath the coastline of central Oregon. Specifically, it occurred on the 16th of May at 4:11 a.m. and rumbled in an area four miles to the east of Copalis Beach. The earthquake measured as a 3.4 on the Richter scale. Because of the depth of this quake and others within this "tremor burst," aftershocks are mostly nonexistent.

Every time a new tremor, quake or temblor rumbles beneath, scientists gain new chances to observe the tectonic behavior with a variety of instruments and calculation. the consensus regarding this specific situation is that the ocean plate is sub-ducting and being tugged, pulled and twisted within the earth's mantle.

Tim Melbourne, with the Northwest Geodetic Array, remarked that any signal his instruments can glean leads to fascinating results. The Northwest Geodetic array is based at Ellensburg's Central Washington University. He went on to mention that the pings of activity are like briefly finding a dangerous and menacing force, like a dragon, in the dark with a flashlight. While a single flash is not very informative by itself, connecting enough instances makes it possible to understand the dragon's behavior. Melbourne finished by stating that this particular dragon, the Cascadia subduction zone, happens to be a very large threat. While subduction zones exist throughout the Pacific rim, they can also be found in other regions.

Our planet's crust consists of plates that float atop the molten rock of the mantle. The floor of the ocean and continental bedrock are two different materials and their meeting point is where subduction zones, like the one stretching from Cape Mendocino, California, to Vancouver Island, British Columbia, form.

Portions of the ocean's floor are being crushed beneath the western edge of North America. Where these two plates collide is the site of a massive fault. The cooler sections of the fault may be interlocked, but in the moments when one gives way, known to happen roughly every 300-500 years, massive earthquakes ensue. The next time this happens along the Pacific coastline, the earthquake is expected to hit magnitude 9. While the last earthquake to strike this area was in 1700, the chaos of Japan in 2011, reeling from earthquakes, tsunamis and the ensuing leak of the Fukushima Daichi nuclear plant as a result of the natural disasters.

While tremors and slips have been recorded throughout the Pacific Northwest on a 14-month schedule since the '90s, the good news is that the shaking is usually unnoticeable and not necessarily a signal of a quake. What researchers connected to the Pacific Northwest Seismic Network (PNSN) do know is that the slips signify a rise in pressure that will eventually result in the foreseen magnitude 9.

The PNSN cautions that slow slips are a very frequent geological occurrence, helping to raise the stress along faults when plates seem otherwise immovable. John Vidale, of the University of Washington and director of PNSN stated that this particular region’s 14-month activity cycle always concludes in a month of shifting to release the built-up stress. He also clarified that the movement of these slips is no more than half an inch every few days, meaning that only the most sensitive of seismological instruments can even recognize when it happens. The PNSN acknowledges that this particular burst of earth tremors is unrelated to the usual 14-month slip cycle; that regular event is anticipated to kickoff somewhere between July and August of this year.