The small Juan De Fuca Plate, moving east-northeast at 4 cm (~1.6 inches) per year, was once part of a much larger oceanic plate called the Farallon Plate. The North American Plate is one of the slowest, averaging around 1 cm/y in the south up to almost 4 cm/y in the north. [2][3], It is generally accepted that a piece of the North American Plate was broken off and transported north as the East Pacific Rise propagated northward, creating the Gulf of California. On its western edge, the Farallon Plate has been subducting under the North American Plate since the Jurassic Period. The southern boundary with the Cocos Plate to the west and the Caribbean Plate to the east is a transform fault, represented by the Swan Islands Transform Fault under the Caribbean Sea and the Motagua Fault through Guatemala. Centralia, Washington, and the Canadia border, The Tsunami At ؛Anaqtl’a or "Pachena Bay". transform plate boundaries. Which of the following best describes the present-day direction and rate of motion of both the Pacific Plate and the North American Plate (refer to Problems 19 & 21)? San Andreas Fault. The North American Plate is a tectonic plate covering most of North America, Cuba, the Bahamas, extreme northeastern Asia, and parts of Iceland and the Azores. While the North American plate in the east moves in the southwest direction, the Pacific plate in the west moves northwest. Q. It is important to remember that the one-minute-long movie actually represents millions of years! In southwestern Alaska, those two plates meet head on, and the Pacific plate sinks beneath the North American plate. Along most of the edges of this craton are fragments of crustal material called terranes, which are accreted to the craton by tectonic actions over a long span of time. Large tectonic plate including most of North America, Greenland and part of Siberia. [citation needed]. Sea floor spreading is occurring at the boundary between the. 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. The locked zone varies in width from a few tens of kilometers (km) along the Oregon coast to perhaps a hundred km or more off of Washington's Olympic Peninsula, and is about 1,000 km long. The Caribbean-North American plate boundary is complex.The Cayman Trough marks the northernwestern limit of the Caribbean plate (Lyon-Caen et al., 2006) and behaves as a transform fault separating oceanic lithosphere of the Caribbean and North American plates.The Motagua fault system continues westward, splitting into several splays of the Polochic and Motagua fault systems. The tectonic plate consists of an oceanic lithosphere originating from the Juan de Fuca ridge close to the region the plate is subductingthe North American continental plate. The rest of the boundary in the far northwestern part of the plate extends into Siberia. Andes Mountains a. The Pacific Plate is moving to the northwest at a speed of between 7 and 11 centimeters (cm) or ~3-4 inches a year. It extends eastward to the Mid-Atlantic Ridge and westward to the Chersky Range in eastern Siberia. The Pacific Plate slides north-northwestward past the North American Plate along the San Andreas Transform Plate Boundary. Northern Japan is largely on top of the western tip of the North American plate. The North American Plate is a tectonic plate covering most of North America, Greenland, Cuba, the Bahamas, extreme northeastern Asia, and parts of Iceland and the Azores. The Northern Pacific plate is sliding laterally past the North American plate in a northerly direction, and hence the San Andreas is classified as a strike-slip fault. The Juan de Fuca Plate is still actively subducting beneath N. America. Pacific Plate is being pushed under the North American Plate 2. With an area of 76 million km2 (29 million sq mi), it is the Earth's second largest tectonic plate, behind the Pacific Plate (which borders the plate to the west). What divides the Pacific and North American tectonic plates? By 20 Ma, the Monterey-Pacific ridge stopped spreading and Monterey accreted to the Pacific plate. 3. On the northerly boundary is a continuation of the Mid-Atlantic ridge called the Gakkel Ridge. The most notable hotspots are the Yellowstone (Wyoming), Jemez Lineament (New Mexico), and Anahim (British Columbia) hotspots. The rest of the southerly margin which extends east to the Mid Atlantic Ridge and marks the boundary between the North American Plate and the South American Plate is vague but located near the Fifteen-Twenty Fracture Zone around 16°N. Question: RECURRENCE TIME OF THE EARTHQUAKE The North American Plate And The Pacific Plate Are Moving Past Each Other At About 5 Cm/yr, But This Slip Is Distributed Along Many Separate Faults. In the intervening region, above the Northern Cordilleran slab window, the volcanism is different, both chemically and physically (Thorkelson et al., 2011). The Gulf is underlain by the Gulf of California Rift Zone, a series of rift basins and transform fault segments between the northern end of the East Pacific Rise in the mouth of the gulf to the San Andreas Fault system in the vicinity of the Salton Trough rift/Brawley seismic zone. The south-eastern side is a divergent boundary with the Nazca Plate forming the East Pacific Rise. The remnant of the Farallon which was not entirely subducted in the north of the Pacific-North American plate transform boundary (at a point named for the juncture of the three tectonic plates: Mendocino Triple Junction) was one solid continuous Juan de Fuca plate. The Farallon Plate has almost completely subducted beneath the western portion of the North American Plate leaving that part of the North American Plate in contact with the Pacific Plate as the San Andreas Fault. These plates move and interact with one another, driven by convectional forces within the Earth. 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. North American & Pacific Plates The picture to the right shows the faults, locked segments, and creeping segments of the North American Fault. Although both plates are moving in a north westerly direction, the Pacific Plate is moving faster than the North American Plate, so the relative movement of the North American Plate is to the south east. Its explanatory gravitas and the weight of observational evidence overcame much initial skepticism over how mobile the Earth's surface really is, and Plate Tectonics quickly became universally accepted by scientists throughout the world. answer choices One recent study suggests that a mantle convective current is propelling the plate.[7]. The interior of the main continental landmass includes an extensive granitic core called a craton. The South Whidbey Island Fault and Darrington Devil's Mountain Fault bound the Everett Basin. SURVEY . Antarctic Plate and Indian Australian Plate boundary. Answer: The correct answer is San Andreas Fault. For example, moving at about 2 inches (5 centimeters) per year, in our lifetime the Pacific Plate moves 10 to 15 feet (3 - 5 meters) past the North American Plate along the San Andreas Fault, a transform plate boundary in California. The north-eastern side is a divergent boundary with the Explorer Plate, the Juan de Fuca Plate and the Gorda Plate forming respectively the Explorer Ridge, the Juan de Fuca Ridge and the Gorda Ridge. Shoveling off all the sedimentary deposits from the basement rocks underlying the Puget Lowland would certainly be one way to reveal this pattern. It is thought that much of North America west of the Rocky Mountains is composed of such terranes. It has a divergent boundary with the Explorer Plate off the west coast of Vancouver Island, Canada. The trench exists because the oceanic Pacific Plate (dark blue on map below) is moving westward, hitting and bending down under the continental Okhotsk Plate … But the central part of the old Farallon plate vanished beneath North America. A few hotspots are thought to exist below the North American Plate. Its motion is not smooth, but rather sticky; strain builds up until the fault breaks and a few meters of Juan De Fuca slips under North America in a big Megathrust earthquake. The map at the top of this page shows the geographic location and extent of 15 major lithospheric plates. The seven major lithospheric plates are: Pacific, North American, South American, Eurasian, Atlantic, Australian-Indian, and Antarctic. The motion of the plate cannot be driven by subduction as no part of the North American Plate is being subducted, except for a small section comprising part of the Puerto Rico Trench; thus other mechanisms continue to be investigated. However, it is as yet unclear whether the oceanic crust east of the Rise and west of the mainland coast of Mexico is actually a new plate beginning to converge with the North American Plate, consistent with the standard model of rift zone spreading centers generally. The Farallon plate used to include what is now 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 between. The North American Plate has a transform boundary with the Pacific Plate, dividing California at the San Andreas Fault. Silicon Valley. Tags: Question 10 . At the same time, the Pacific Plate is moving to the northwest at a speed of between 7 and 11 centimeters (~3-4 inches) a year. 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. ... Juan de Fuca Plate and North American Plate boundary. 30 seconds . The plate includes both continental and oceanic crust. 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 hazard. Place the Pacific Plate over the previously marked points on the remaining transparency sheet, and tape it into position. The Pacific Plate constitutes most of the seafloor of the Pacific Ocean. This map of gravity residuals measured over the puget lowland reveals a pattern of deep, fault bounded basins (cool colors) and uplifts (warm colors). This block of crust is rotated west and pushed north into Washington state. Oceanic crust is sliding beneath the Aleutian Islands in the North Pacific Ocean, forming the Aleutian Trench at a. answer choices . Notice the Seattle Fault Zone bounding the Seattle Basin to the south. With an area of 76 million km (29 million sq mi), it is the Earth's second largest tectonic plate, behind the Pacific Plate (which borders the plate to the west). The Best Estimate For The Section Of The San Andreas Of Interest Here Is 14 Mm/yr. Its depth is comparable to the deep trenches in the Pacific Ocean. The Puerto Rico Trench (Figure 2) lies to the north of Puerto Rico and is the deepest part of the Atlantic Ocean, with water depths exceeding 8,300 meters (5.2 miles). This particular plate tectonic covers most of North America, Greenland, Cuba, Bahamas, northeastern Asia, parts of Iceland, … These are thought to be caused by a narrow stream of hot mantle convecting up from the Earth's core–mantle boundary called a mantle plume,[4] although some geologists think that upper mantle convection is a more likely cause. In California, much of the strain generated by the grinding of the Pacific Plate against North America is taken up in earthquakes on the San Andreas Fault and related structures, but the shearing action doesn't end there. What divides the Pacific and North American tectonic plates? This may seem like small and slow motion but over geologic time scales these movements add up to hundreds and thousands of kilometers, and can reform parts of the surface of Earth. Categories Question-Answer. The outermost part of Earth's structure is known as the lithosphere. British Columbia, however, is part of rigid North America and moves with it. Fortunately geophysics allows us an much easier way to uncover the basement--measure the gravity. The boundary along the Gulf of California is complex. Plate tectonics is a relatively young scientific theory that needed the advancement of observational and computing technology in the 1950s and 1960s to become fully elaborated. The Sierra Nevada block is driven north-northwest into the Oregon Coastal Range. The Yellowstone hotspot is most notable for the Yellowstone Caldera and the many calderas that lie in the Snake River Plain while the Anahim hotspot is most notable for the Anahim Volcanic Belt, currently found in the Nazko Cone area. Geologic timeline of Western North America, "Sizes of Tectonic or Lithospheric Plates", "Landslides, Floods, and Marine Effects of the Storm of January 3-5, 1982, in the San Francisco Bay Region, California", "Farallon Plate [This Dynamic Earth, USGS]", "Upper-mantle origin of the Yellowstone hotspot", https://en.wikipedia.org/w/index.php?title=North_American_Plate&oldid=1005079654, Short description is different from Wikidata, Articles with unsourced statements from April 2010, Creative Commons Attribution-ShareAlike License, This page was last edited on 5 February 2021, at 22:05. Ex. Use the graph above to determine the approximate latitude of the Aleutian trench at 180° W longitude. Far to the north, subduction of the Pacific plate beneath Alaska is generating the Aleutian volcanic arc. This boundary continues from the end of the Gakkel Ridge as the Laptev Sea Rift, on to a transitional deformation zone in the Chersky Range, then the Ulakhan Fault between it and the Okhotsk Plate, and finally the Aleutian Trench to the end of the Queen Charlotte Fault system. On its northern side, the Plate subducts under the North-American Plate, forming a convergent boundary and the Aleutian Trench along the islands of the same name. The San Andreas Fault is responsible for most of the movement in western California, causing a sliver of the state to slide past the rest of the continent. The Pacific Plate is moving to the northwest at a speed of between 7 and 11 centimeters (cm) or ~3-4 inches a year. Nazca Plate subducted under the South American plate ii. The Juan de Fuca, Explorer, Gorda, Rivera, Cocos and Nazca plates are remnants of the Farallon Plate. convergent plate boundary between the Pacific Plate and the North American Plate. The San Andreas transform boundary between the Pacific and North American plate originates from the shallow, oblique subduction by the North American plate of the Monterey microplate (a fragment of the Farallon plate sharing a spreading ridge with the Pacific plate) (Nicholson, 1994). The east-side of the North American Plate straddles the Eurasian Plate and African Plate.This is the Mid-Atlantic Ridge where divergent tectonic plates pull apart from each other. The Pacific Plate is being moved north west due to sea floor spreading from the East Pacific Rise (divergent margin) in the Gulf of California. Leave a Reply Cancel reply. The San Andreas fault system, and associated fault systems within southern and central California are a result of the Pacific Plate moving northwest along the North American Plate… Sacramento River. 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. This animation shows, in a very exaggerated way, the sorts of movements Plate Tectonics implies. Plate tectonics describes the motions of the 15 to 20 large rigid and brittle tectonic plates into which the Earth's outermost layer (called the "lithosphere") is broken. Dr. Ray Wells of the USGS developed a model to demonstrate this process and produced the cartoon animation located above the GPS Vector map. These plate motions are the primary source of strain in the lithosphere that lead to earthquakes in our region. What divides the Pacific and North American tectonic plates? Ocean plate goes down and pushes the continental plate up cause mountain range cause mountain range Your email address will not be published. The oldest lithosphere is found at the southern end and is approximately nine million years old while the youngest is located at the Nootka Fault and is thought to be around six million years old. Trenches in the Pacific are located in places where one tectonic plate subducts or slides under another one. The plate is presently shrinking as the Atlantic Ocean increases in size pushing the North American Plate slowly westward. 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. The parallel Septentrional and Enriquillo–Plantain Garden faults, which run through the island of Hispaniola and bound the Gonâve Microplate, are also a part of the boundary. This plate forms a large portion of the Pacific Ring of Fire. The Pacific Plate is the largest crustal plate on our planet. Align the rotation pole marks for the transparency and the North American Plate and push the thumbtack on through. The Pacific-North American plate boundary resulted in a transform convergence zone. 1. In the middle of the eastern side is a transform boundary with the North American Plate along the San Andreas Fault, and a boundary with the Cocos Plate. The Pacific Plate stretches all the way along the west coast of North America up to Alaska. The subduction zones surrounding the Pacific Plate are overriding the heavier and denser Pacific Plate. Applying Concepts The Aleutian trench is located where the two tectonic plates meet at the surface of the lithosphere. At the western edge, it reaches all the way to the east coast of the islands of Japan and Indonesia. North American Plate Movement. Mount Tam. But that would involve way too much digging! The volcanic chain that forms the Aleutian Islands and continues into the… The Pacific Plate is the fastest at over 10 cm/y in some areas, followed by the Australian and Nazca Plates. However, 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. Ex. Nazca Plate and Pacific Plate boundary. Push the thumbtack through the sheet from underneath, at the point corresponding to the rotation pole. This action takes place along the interface between the plates from the Juan de Fuca Trench offshore down-dip until the fault is too weak to store up any elastic stress. Think about … Beyond merely describing current plate motions, Plate Tectonics provides an overarching framework that connects many elements of Earth science. Japan's stretch of the Ring of Fire is where the North American, Pacific, Eurasian and Philippine plates come together. In this subduction zone, some of the ocean plate melts and the molten rock pushes to the surface in a string of 40 active volcanoes, forming the Aleutian Islands. The Pacific Plate (on the west) slides horizontally northwestward relative to the North American Plate (on the east), causing earthquakes along the San Andreas and associated faults. It takes a lot of slip (10s of meters) over a very large area to generate the M9 subduction zone earthquakes that rock our region ~ every 550 years on average. The San Andreas fault is a transform plate boundary, accomodating horizontal relative motions. It was subducted beneath California leaving the San Andreas fault system behind as the contact between the North America and Pacific plates. [5][6] The Yellowstone and Anahim hotspots are thought to have first arrived during the Miocene period and are still geologically active, creating earthquakes and volcanoes. In turn, we find some of the youngest geologic rocks at these mid-oceanic ridges. For the most part, the North American Plate moves in roughly a southwest direction away from the Mid-Atlantic Ridge at a rate of about 2.3 centimeters (~1 inch) per year. The lithosphere consists of the crust and small portion of the upper mantle. Both the Gorda and Explorer plates are less than six million years old. The lithosphere is divided into a number of tectonic plates. The westerly boundary is the Queen Charlotte Fault running offshore along the coast of Alaska and the Cascadia subduction zone to the north, the San Andreas Fault through California, the East Pacific Rise in the Gulf of California, and the Middle America Trench to the south. Continental Hot Spots - Hawaiian Island-Emperor Seamount Chain & Yellowstone Hot-Spot Trail. This results in the Puget Lowland being compressed and warped like an accordion with alternating uplifted and down warped terrain shortening the distance between Centralia, Washington, and the Canadia border.