Two M5.4, a M5.0, Two M4.2 and a M4.7!
A series of earthquakes off the Oregon coast were recorded Saturday by the US Geologic Survey. Is Cascadia waking up?
The quakes were recorded at 5:43 a.m., 5:52 a.m., 6 a.m., 6:16 a.m., 6:37 a.m. and 6:40 a.m. The quakes registered between a 5.4 and 4.7.
The alert level is green, meaning there is a low likelihood of casualties or damage.
The quakes were more than 200 miles west of the Oregon coast.
The USGS said the distance between the quakes’ epicenter to Bandon was 208 miles, 213 miles to Coos Bay and 221 miles to Newport.
As you see on the above map, the quakes are not directly on the Cascadia subduction zone, but on the Blanco Fracture Zone, a right lateral transform fault zone, which runs northeast off the coast of Oregon in the Pacific Northwest of the United States, extending from the Gorda Ridge in the south to the Juan de Fuca Ridge in the north.
The subducting Gorda Plate is connected with the volcanoes in northern California, namely, Mount Shasta and Lassen Peak. Lassen Peak last erupted in 1914–1917.
Previous swarms
On January 9th 1994, a large series or swarm of earthquakes occurred in the East Blanco Depression. Acoustic signals recorded during these events indicated that an eruption occurred in this zone. Further investigation revealed an active hydrothermal vent, the first of its kind to be discovered in a transform fault zone.
In March and April 2008, a swarm of moderate earthquakes occurred both near and within the Blanco zone. The swarm began on March 30 when over 600 measurable tremors began occurring north of the zone within the Juan de Fuca Plate. On April 23, activity moved to the Blanco fault zone itself, near its junction with the Gorda Ridge.
Another series of earthquakes occurred in June 2015. Spread out over a period of a few days, some reached magnitudes of 5.8.
In any cases, all those plates are interconnected and if one starts to really move, it could also start destabilizing others and end up with the Big One!
