what will eventually happen to the juan de fuca plate

Plate tectonics describes the motions of the xv to 20 large rigid and brittle tectonic plates into which the Earth's outermost layer (chosen the "lithosphere") is broken. It does a good job at explaining the distribution of most of Earth's earthquakes, mountains and other geological features, and a particularly good job at explaining features on the ocean floor. Nonetheless, it is challenged to explain the details of the older rocks on the continents, and the occurrence of deformation and earthquakes off of plate boundaries.

Beyond only describing current plate motions, Plate Tectonics provides an overarching framework that connects many elements of Earth scientific discipline. Plate tectonics is a relatively young scientific theory that needed the advancement of observational and calculating engineering science in the 1950s and 1960s to become fully elaborated. Its explanatory gravitas and the weight of observational evidence overcame much initial skepticism over how mobile the Earth'southward surface really is, and Plate Tectonics quickly became universally accepted by scientists throughout the earth.

This animation shows, in a very exaggerated way, the sorts of movements Plate Tectonics implies. Plate Tectonics is a theory of motions at the Earth's surface, but to drive those motions, it relies on a planet with a very active inner life. It is important to remember that the one-infinitesimal-long film really represents millions of years!

This is a map of the main tectonic plates that comprise the Earth's surface:

In the Pacific Northwest, movement of three tectonic plates drive our earthquake adventure. The Pacific Plate is moving to the northwest at a speed of betwixt 7 and eleven centimeters (cm) or ~3-iv inches a year.

The North American plate is moving to the west-southwest at about 2.3 cm (~one inch) per year driven by the spreading center that created the Atlantic Ocean, the Mid Atlantic Ridge. This may seem like modest and slow motion simply over geologic fourth dimension scales these movements add upwards to hundreds and thousands of kilometers, and can reform parts of the surface of Globe.

The pocket-sized Juan De Fuca Plate, moving east-northeast at iv cm (~1.6 inches) per year, was once part of a much larger oceanic plate chosen the Farallon Plate. The Farallon plate used to include what is at present the Cocos Plate off Mexico and Central America and the Juan de Fuca Plate in our region from N. Vancouver Island to Cape Mendocino California and a large tract of seafloor real estate in betwixt. But the key part of the old Farallon plate vanished beneath North America. It was subducted beneath California leaving the San Andreas fault system behind as the contact between the N America and Pacific plates.

The Juan de Fuca Plate is still actively subducting below N. America. Its motion is not smooth, but rather sticky; strain builds upwards until the mistake breaks and a few meters of Juan De Fuca slips under North America in a big Megathrust earthquake. This action takes place forth the interface betwixt the plates from the Juan de Fuca Trench offshore down-dip until the error is too weak to store up any elastic stress. The locked zone varies in width from a few tens of kilometers (km) along the Oregon coast to perchance a hundred km or more than off of Washington's Olympic Peninsula, and is about i,000 km long. It takes a lot of sideslip (10s of meters) over a very large surface area to generate the M9 subduction zone earthquakes that stone our region ~ every 550 years on average.

These plate motions are the primary source of strain in the lithosphere that lead to earthquakes in our region. In California, much of the strain generated past the grinding of the Pacific Plate against North America is taken up in earthquakes on the San Andreas Mistake and related structures, but the shearing activeness doesn't end there.

The Sierra Nevada cake is driven north-northwest into the Oregon Coastal Range. This cake of chaff is rotated west and pushed north into Washington state.

British Columbia, nevertheless, is part of rigid North America and moves with it. This results in the Puget Lowland beingness compressed and warped like an accordion with alternating uplifted and downwards warped terrain shortening the distance betweenCentralia, Washington, and the Canadia border. Dr. Ray Wells of the USGS developed a model to demonstrate this process and produced the cartoon animation located above the GPS Vector map.

Shoveling off all the sedimentary deposits from the basement rocks underlying the Puget Lowland would certainly be 1 fashion to reveal this pattern. But that would involve way too much digging! Fortunately geophysics allows us an much easier style to uncover the basement--measure the gravity.

This map of gravity residuals measured over the puget lowland reveals a pattern of deep, fault divisional basins (cool colors) and uplifts (warm colors). Observe the Seattle Mistake Zone bounding the Seattle Basin to the due south. The S Whidbey Island Fault and Darrington Devil'due south Mountain Fault bound the Everett Basin.

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Source: https://pnsn.org/outreach/about-earthquakes/plate-tectonics

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