Oceanic crust forms by eruptions along the Juan de Fuca Ridge. As the Juan de Fuca Plate drifts
eastward, it cools, becomes more dense
, and eventually dives under the less dense North American Plate at the Cascadia Trench.
Is the Juan de Fuca Plate subducting under the North American Plate?
This plate is moving northeastward relative to North America along a convergent plate boundary such that the Juan de Fuca plate is
subducting beneath
the North American plate at the Cascadia trench at an approximate rate between 9.8 and 13.8 feet per 100 years.
What feature is created when the Juan de Fuca Plate subducts under the North American Plate?
The Juan de Fuca Plate, east of this spreading centre, is subducting under the North American Plate. The molten mantle rock produced by this subduction is responsible for
the major volcanoes in the Cascade Range
.
What type of plate boundary is the Juan de Fuca Plate and the North American Plate if there is evidence of deep earthquakes and abundant volcanoes?
There are three different sources for damaging earthquakes in the Pacific Northwest. The first of these is the “Cascadia Subduction Zone”, a 1000 km long thrust fault which is the
convergent boundary
between the Juan de Fuca and North American plates and is the most extensive fault in the Pacific Northwest area.
Which type of plate boundary separates the North American and Juan de Fuca plates?
As the mid-ocean ridge separating the Farallon and Pacific Plates entered the subduction zone, the Farallon Plate separated into the Juan de Fuca and Cocos Plates.
A transform plate boundary
developed where the Pacific Plate was in contact with the North American Plate and the volcanism ceased in central California.
What is the biggest tectonic plate?
There are major, minor and micro tectonic plates. There are seven major plates: African, Antarctic, Eurasian, Indo-Australian, North American, Pacific and South American. The Hawaiian Islands were created by
the Pacific Plate
, which is the world’s largest plate at 39,768,522 square miles.
What is the smallest plate?
| Juan de Fuca Plate | Speed 1 26 mm/year (1.0 in/year) | Features Pacific Ocean | 1 Relative to the African Plate |
|---|
Is the Juan de Fuca plate getting bigger or smaller?
The Juan de Fuca plate offshore of Oregon, Washington and British Columbia is
small
– about the size of California and 50-70 kilometers thick – but “big enough to generate magnitude 9 earthquakes” as it’s shoved under the continental North American plate, Allen said.
What direction is the North American Plate moving?
The North American plate is moving to
the west-southwest
at about 2.3 cm (~1 inch) per year driven by the spreading center that created the Atlantic Ocean, the Mid Atlantic Ridge.
Why are earthquakes associated with rifts?
The majority of deep crustal earthquakes occur along the rift margins in regions that have cooler, thicker crust. … We believe the deep crustal earthquakes represent either the
relative motion of rift zones with respect to adjacent stable regions
or the propagation of rifting into stable regions.
Which type of waves may cause the worst damage?
S waves
are more dangerous than P waves because they have greater amplitude and produce vertical and horizontal motion of the ground surface. The slowest waves, surface waves, arrive last. They travel only along the surface of the Earth. There are two types of surface waves: Love and Rayleigh waves.
When two continental plates collide it is called?
Convergent boundaries
include when two continental plates collide, two oceanic plates converge or when an oceanic plate meets a continental plate. Several events can occur. Generally, when the oceanic plate hits a continental one, the continental plate uplifts, and the oceanic plate goes beneath it or subducts.
Is the Nazca plate convergent or divergent?
The Nazca plate is an oceanic tectonic plate in the southeastern Pacific Ocean that shares
both convergent and divergent boundaries
, corners multiple triple junctions, contains three seamount chains, overrides four hotspots, and is responsible for the creation of the Andean orogeny (Figure 1).
How thick is the Juan de Fuca plate?
Plate tectonics
The Juan de Fuca plate offshore of Oregon, Washington and British Columbia is small — about the size of California and
50-70 kilometers thick
— but “big enough to generate magnitude 9 earthquakes” as it’s shoved under the continental North American plate, Allen said.
Why do tectonic plates move?
The heat from radioactive processes within the planet’s interior causes the plates
to move, sometimes toward and sometimes away from each other. This movement is called plate motion, or tectonic shift.
