Figure 19.1. Landscape map that shows the US part of the Juan de Fuca plate . The Juan de Fuca and Gorda ridges mark the divergent plate boundary (the spreading ridge) with the Pacific plate. The Cascadia trench marks the subduction zone with the North American plate.
Is the Pacific Plate under the North American Plate?
The floor of the Pacific Ocean is divided into several plates. The largest one, the Pacific Plate is moving north west relative to the plate that holds North America , and relative to hot spots coming up through the mantle from below the plates (they generate islands like Hawaii).
Is the Pacific plate subducting under the North American plate?
The oceanic Pacific Plate subducts under the North American Plate (composed of both continental and oceanic sections) forming the Aleutian Trench. ... The South American Plate is subducting under the South Sandwich Plate, forming the South Sandwich Trench.
Which direction is the Pacific Plate subducting?
The very large Pacific Plate, which underlies most of the northern and western Pacific basin, moves north-northwest with respect to North America nearly parallel to the coast, and is subducted beneath southern Alaska and the Aleutians.
Is Pacific Plate overriding plate or subducting plate?
The Pacific Plate is subducting underneath the North American Plate . The downgoing slab of the Pacific Plate at the subduction zone heats up and partially melts causing magma to rise up through the overriding plate resulting in the formation of volcanoes.
Which direction is the Eurasian plate and North American Plate moving?
The North American Plate, for example, rotates counter-clockwise; the Eurasian Plate rotates clockwise . Boundaries between the plates are of three types: divergent (i.e., moving apart), convergent (i.e., moving together), and transform (moving side by side).
What are the two plates at the major plate boundary of the most seismically active area of North America?
The San Andreas Fault , stretching along the central west coast of North America, is one of the most active faults on the Ring of Fire. It lies on the transform boundary between the North American Plate, which is moving south, and the Pacific Plate, which is moving north.
Is the Farallon Plate the same as the Pacific plate?
As those plates converged, much of the Farallon was subducted underneath North America and eventually sank deep into the mantle. Off the west coast of North America, the Farallon plate fragmented, leaving a few small remnants at the surface that stopped subducting and became part of the Pacific plate.
Does the Farallon Plate still exist?
The remains of the Farallon Plate are the Juan de Fuca, Explorer and Gorda Plates , subducting under the northern part of the North American Plate; the Cocos Plate subducting under Central America; and the Nazca Plate subducting under the South American Plate.
Why are the tectonic plates moving?
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.
Which direction is the Pacific Plate currently moving?
The Pacific Plate is moving to the northwest at a speed of between 7 and 11 centimeters (cm) or ~3-4 inches a year. 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.
What is the largest tectonic plate?
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 are 4 plates that underlie the Pacific Ocean?
However, the Pacific Plate, Cocos Plate, Nazca Plate, and Antarctic Plate move more than 10 centimeters which is the fastest movement rate of all plate tectonics.
What happens when two plate collide?
If two tectonic plates collide, they form a convergent plate boundary . Usually, one of the converging plates will move beneath the other, a process known as subduction. ... The new magma (molten rock) rises and may erupt violently to form volcanoes, often building arcs of islands along the convergent boundary.
What type of boundary is between the Pacific Plate and North American Plate?
San Andreas Transform Plate Boundary
The transform plate boundary between the Pacific and North American Plates in western California formed fairly recently. About 200 million years ago, a large tectonic plate (called the Farallon Plate) started to subduct beneath the western edge of North America.
Where do the worst earthquakes happen?
The world's greatest earthquake belt, the circum-Pacific seismic belt , is found along the rim of the Pacific Ocean, where about 81 percent of our planet's largest earthquakes occur. It has earned the nickname “Ring of Fire”. Why do so many earthquakes originate in this region?
