Multiple complex plate boundaries contribute lots of earthquake and volcanic activity in the region. The explanation is that plates move in a rotational manner. Visitors can witness mountains as they are forming, and sometimes experience the accompanying earthquake and volcanic activity. The boundary between the two plates is the Nootka Fault, which is the location of frequent small-to-medium earthquakes (roughly up to magnitude 5), as depicted by the red stars. Redoubt, on the eastern side of the park, had four explosive eruptions that resulted in large volumes of ash and mudflows. The fact that the plates include both crustal material and lithospheric mantle material makes it possible for a single plate to be made up of both oceanic and continental crust. This plate includes all of Africa and the surrounding ocean, including the eastern Atlantic Ocean, the surrounding Antarctic Ocean, and the western Indian ocean. When mixed with water from glaciers, snowmelt, and streams, these materials can make very dense, fast-moving volcanic mudflows (known sometimes by the Indonesian term lahar). USGS photo. Question: Tectonic Plates Use this map to answer the following questions. North America plate, Australia plate, Antarctic plate, Nazca plate, Filipino plate, Cocos plate, Juan de Fuca plate. Images above modified from Oregon's Island in the Sky: Geology Road Guide to Marys Peak, by Robert J. Lillie, Wells Creek Publishers, 75 pp., 2017, www.amazon.com/dp/1540611965. The volcanoes are forming above the region where the top of the subducting Juan de Fuca Plate reaches about 50 miles (80 kilometers) depth. If the seafloor rises or falls, giant sea waves (a tsunami) can form. Aniakchak National Monument and Preserve is on the Alaska Peninsula. A variety of earthquakes shake the Pacific Northwest due to plate-tectonic activity. Two arms of the triple junction can split to form an entire ocean. Mt. A glance at a map of the western United States might suggest that the Sierra Nevada are a southward continuation of the Cascade Volcanoes. Based on Keary and Vine, 1996, Global Tectonics (2ed), Blackwell Science Ltd., Oxford. (Click on arrows and slide left and right to see labels.). Stack the quarters with Washington on top, Oregon in the middle and California on the bottom. Off the Pacific coast, the Cocos plate is subducted beneath both the North American and Caribbean plates, which are separated by a sinistral transcurrent boundary. South America plate, Pacific plate, Antarctic plate, Cocos plate. Mazama, Aniakchak spewed lava across its caldera floor for centuries after its collapse. Download the official NPS app before your next visit, Accretionary WedgeCoast Ranges [3 parks], Accretionary WedgeSouthern Alaska [1park]. 20 Million Years Ago The overlying volcanoes have since eroded away, exposing a vast expanse of the ancient magma chambers in the Sierra Nevada. Over the next 50 million years, it is likely that there will be full development of the east African rift and creation of new ocean floor. That the Atlantic Ocean rift may have occurred in approximately the same place during two separate events several hundred million years apart is probably no coincidence. Adding TravelTime as Impedance in ArcGIS Network Analyst? National Park Service Sites in the Southern Alaska Subduction Zone reveal a variety of active volcanic features above the zone where the top of the Pacific Plate reaches sufficient depth where temperature and pressure are high enough to dehydrate rocks and form magma. What plate boundary shows the collision of two plates? Remove the Oregon quarter to reveal cooled magma chamber rocks below. Credit: Photo courtesy of Robert J. Lillie. Some geological processes act so slowly that we may think of the Earth as rock-solid and unmoving. Layers of sand and mud, deposited on the ocean floor and later turned into the sedimentary rocks sandstone and shale, are seen above the pillows. Basalt lava is thin and runny and will flow for miles and miles. , Divergent boundaries where two plates are moving apart. Right image If this continues without changing for another couple hundred million years, we will be back to where we started, with one supercontinent. It formed millions of years ago when the Farallon Plate split into the Cocos Plate and the Nazca Plate.. Trees along the Washington coast were killed by salt-water invasion when the land suddenly dropped during the last great Cascadia Subduction Zone earthquake in the year 1700. The Cocos Plate is a small, oceanic plate just to the west of Central America. Photo courtesy of Robert J. Lillie. The rocks on top of the plate are metamorphosed due to the great temperatures and pressures at those depths. The part of the plate around the South America plate is moving northwards and a little east. Garibaldi to Lassen Peak, coincides with the north-to-south extent of the subducting plate boundary. The Cascadia Subduction Zone and Southern Alaska are the sites of ongoing subduction as the Pacific and Juan de Fuca plates slide beneath the North American Plate. On Dec. 15, 1989 a jet with 244 passengers and crew was en route from Amsterdam to Anchorage. The Guerrero and Oaxaca regions of southern Mexico also experience regular SSEs. Igneous, sedimentary, and metamorphic rocks are all found in abundance. After a terrifying free-fall that lasted 8 minutes, the pilots finally managed to restart the engines at only 6,000 feet (2,000 meters). The caldera has partially filled with water an approximately half-scale version of the better-known Crater Lake in Oregon. Answers for geologist, scientists, spacecraft operators. The Cocos Plate is subducting beneath the Caribbean Plate, while the Caribbean Plate is subducting below both the Panama Plate and the North Andean Plate. This plate is rotating in a clockwise direction towards the Pacific plate. For example the Juan de Fuca Plate is actually three separate plates (Gorda, Juan de Fuca, and Explorer) that all move in the same general direction but at slightly different rates. A divergent boundary occurs when two tectonic plates move away from each other. Kenai Fjords National Park lies within a coastal mountain range (accretionary wedge) formed as the Pacific Plate subducts beneath southern Alaska. The Philippine Plate, also known as the Philippine Sea Plate, is a small tectonic plate between the Eurasian Plate and the Pacific Plate. Increased temperature and pressure at that depth cause the rocks to metamorphose and dehydrate (sweat). National Park Service sites in the Cascades reveal colorful landscapes that result from a varity of volcanic processes. Visits to coastal NPS sites in the Pacific Northwest can help us appreciate the landscapes that develop over time because of these large quakes, and learn how we are preparing our homes, communities, and infrastructure for the next Big One.. This plate moves north and slightly west towards the Caribbean plate and the North America plate. The Cascade Volcanoes extend in a north-south line from Mt. Between 200 and 150 Ma, rifting started between South America and Africa and between North America and Europe, and India moved north toward Asia. There are also numerous small plates (e.g., Juan de Fuca, Cocos, Nazca, Scotia, Philippine, Caribbean), and many very small plates or sub-plates. Much of the stable plate is under water and is called the Caribbean ocean . Crater Lake in Crater Lake National Park partially fills the large depression formed when a composite volcano erupted and collapsed in on itself 7,700 years ago. During the same period, the Atlantic Ocean began to open up between northern Africa and North America, and India broke away from Antarctica. Most of this water is present within the sheet silicate mineral serpentine which is derived from alteration of pyroxene and olivine near the spreading ridge shortly after the rocks formation. A convergent plate boundary is a location where two tectonic plates are moving toward each other, often causing one plate to slide below the other (in a process known as subduction). The southerly side is a divergent boundary with the Antarctic Plate called the Southeast Indian Ridge (SEIR). As explained above, most transform faults connect segments of mid-ocean ridges and are thus ocean-ocean plate boundaries (Figure \(\PageIndex{11}\)). The eruption of Aniakchak Volcano about 3,500 years ago rivals the eruption and collapse of Mt. The devastating 1985 Mexico City earthquake and the 2017 Chiapas earthquake were results of the subduction of the Cocos Plate beneath the North American Plate. They are part of the volcanic arc that extends northeastward from the Aleutian Islands, across the Alaska Peninsula and Aniakchak National Monument, Katmai and Lake Clark national parks, and then bends eastward to Wrangell-St. Elias National Park. In this region, the Cocos Plate is subducting beneath the North America and Caribbean Plates (ocean-continent convergence), and the South and North America Plates are subducting beneath the Caribbean Plate (ocean-ocean convergence). The Philippine Sea Plate has an area of approximately 3400 square kilometers. This plate includes all of Saudi Arabia, and much of the Levant (up to Iraq and Syria). The types are ocean-ocean, ocean-continent, and continent-continent. The park is right above the focus of the Great Alaska Earthquake of 1964, one of the two largest ever recorded (the other, in 1961, occurred along the subduction zone off western South America). Cocos Plate; Type: Minor: Approximate area: 2,900,000 km 2: Movement 1: north-east: Speed 1: 67 mm/year: . Mount Rainier is a 14,000 foot (4,300 meter) volcano in the Cascade Range developed above the place where the subducting Juan de Fuca Plate reaches sufficient depth to release hot fluids into the overriding North American Plate. State quarters can be used to demonstrate the current and ancient volcanic landscapes of the Pacific Northwest and California. Unclick all the other layers you've been using, and then click next to . Crater Lake partially fills the caldera of a volcano that erupted and collapsed in on Itself 7,700 years ago. Kenai Fjords National Park This affects not only plant and animal communities, but also human habitation and land use. In central and southern California the ancient volcanoes have largely eroded away. It is subducting under (that is, being forced under) the South American plate. In 1912 the Katmai region erupted an estimated 7 cubic miles (30 cubic kilometers) of ash and pyroclastic material, roughly 50 times the amount that came out of Washingtons Mt. Is the Cocos Plate convergent or divergent? Step 2/2. Is the Nazca plate convergent or divergent? This highly active convergent plate boundary extends along both sides the Philippine Islands, from Luzon in the north to the Celebes Islands in the south. Four-letter codes indicate the ancient volcanic arc parks listed near the top of this page. The Cocos Plate is a relatively small sized, triangular-shaped oceanic plate located just west of Mexico and the Caribbean. Modified from Parks and Plates: The Geology of our National Parks, Monuments and Seashores, by Robert J. Lillie, New York, W. W. Norton and Company, 298 pp., 2005, www.amazon.com/dp/0134905172. A sudden unlocking could produce an earthquake every bit as big as the one that occurred in Alaska in 1964, when a similar subduction zone boundary snap occurred. The LibreTexts libraries arePowered by NICE CXone Expertand are supported by the Department of Education Open Textbook Pilot Project, the UC Davis Office of the Provost, the UC Davis Library, the California State University Affordable Learning Solutions Program, and Merlot. The spectacular pillow lavas seen on the road up Hurricane Ridge indicate that lava formed on the sea floor and was later uplifted. Copalis River, Washington Layers of pillow basalt exposed at NPS sites in the Coastal Ranges are evidence that lava flows that formed in the Pacific Ocean were later scraped off the subducting plate and lifted upward as part of the accretionary wedge. Plates are thought to move along the lithosphere-asthenosphere boundary, as the asthenosphere is the zone of partial melting. Volcanic and metamorphic rocks exposed in Kenai Fjords National Park reveal the incredible forces that occur at an ocean/continent subduction zone. Plates move as rigid bodies, so it may seem surprising that the North American Plate can be moving at different rates in different places. Modified from Beauty from the Beast: Plate Tectonics and the Landscapes of the Pacific Northwest, by Robert J. Lillie, Wells Creek Publishers, 92 pp., 2015, www.amazon.com/dp/1512211893. The series of hot spots that has been identified in the Atlantic Ocean may also have existed for several hundred million years, and thus may have contributed to rifting in roughly the same place on at least two separate occasions (Figure \(\PageIndex{13}\)). We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and 1413739. Beginning about 30 million years ago, so much of the Farallon Plate was consumed by subduction that the Pacific and North American plates were in contact, forming the San Andreas transform plate boundary in western California. The Cocos plate is found on the west side of Mexico. 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. In the past, that was true. As originally described by Wegener in 1915, the present continents were once all part of a supercontinent, which he termed Pangea (meaning all land). Farther inland, the subducting plate reaches depths where it sweats hot water. Other rocks seen in the high mountains at the center of the park were pushed more deeply into the Earth, where increasing temperature and pressure changed them into metamorphic rocks known as quartzite and slate. Individual earthquakes can offset or lift the land a fraction of an inch or a few inches (centimeters) at a time. Mount Rainier National Park showcases a 14,411-foot (4,393-meter) composite volcano. The rising water melts rock in its path, forming a volcanic arc on the overrriding plate. This contortion attests to the great forces that squeezed and lifted the layers from the sea. The Cocos Plate was created approximately 23 million years ago when the Farallon Plate broke into two pieces, which also created the Nazca Plate. The Cascadia Subduction Zone has two parallel mountain ranges separated by a low region near sea level. Most divergent boundaries are located along mid-ocean oceanic ridges (although some are on land). Along these boundaries, earthquakes are common and magma (molten rock) rises from the Earths mantle to the surface, solidifying to create new oceanic crust. What type of boundary is the Philippine plate? This plate is moving directly east towards the South America plate. Feature labels. The largest earthquakes occur near the surface where the subducting plate is still cold and strong. To see the timing of these processes for yourself, go to time lapse of Continental Movements. If two tectonic plates collide, they form a convergent plate boundary. It is released when the oceanic crust is heats and then rises and mixes with the overlying mantle. Transform faults do not just connect divergent boundaries. The eastern margins of North and South America and the western margins of Europe and Africa are called passive margins because there is no subduction taking place along them. The Pacific Plate is the fastest, followed by the Australian and Nazca Plates. Once youve named most of the plates, draw arrows to show the general plate motions. 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 initial magma formed as mantle rock melts beneath a subduction zone has low silica (basalt) composition. Colors denote depth below sea level and elevation on land. Mantle flow in the RiveraCocos subduction zone | Geophysical Journal International | Oxford Academic Summary. Half Dome in Yosemite National Park is made of granite that solidified from magma tens of millions of years ago, when a subduction zone extended along the entire west coast. This plate is moving northwest towards the Australia, Filipino, and Eurasia plates. When the plates suddenly let go, a massive earthquake will shake the entire Pacific Northwest, a series of tsunami waves will pound the Coast, and landslides will make it difficult to reach some of those in need. This plate is moving north east towards the Eurasia plate. These mega-earthquakes occur every 200 to 600 years or so, and the last one was in the year 1700. Because the oceanic crust formed by spreading on the mid-Atlantic ridge is not currently being subducted (except in the Caribbean), the Atlantic Ocean is slowly getting bigger, and the Pacific Ocean is getting smaller. Introduction The Cocos Plate is a relatively small sized, triangular-shaped oceanic plate located just west of Mexico and the Caribbean. Remove the Washington quarter and you can see what the landscape might look like, in the form of Crater Lake in Crater Lake National Park in Oregon. 100% (1 rating) SOLUTION: * The plate boundaries moving towards each other are called the convergent plate boundaries. A by-product of the metamorphism is the release of hot fluids, especially water. An example is the San Andreas Fault, which extends from the southern end of the Juan de Fuca Ridge to the northern end of the East Pacific Rise (ridge) in the Gulf of California (Figures 10.28 and 10.29). If spreading along the mid-Atlantic ridge continues to be slower than spreading within the Pacific Ocean, the Atlantic Ocean will start to close up, and eventually (in a 100 million years or more) North and South America will collide with Europe and Africa. Compaction in the Rock Cycle: Understanding the Process Behind Sedimentary Rock Formation, Crystallization in the Water Cycle: A Fundamental Process in Water Distribution and Purification, Understanding Crystallization in the Rock Cycle: A Fundamental Process in Rock Formation, Extracting Lat/Lng from Shapefile using OGR2OGR/GDAL. A continent-continent collision occurs when a continent or large island that has been moved along with subducting oceanic crust collides with another continent (Figure \(\PageIndex{8}\)). The part of California west of the San Andreas Fault and all of Baja California are on the Pacific Plate. For example, the Queen Charlotte Fault connects the north end of the Juan de Fuca Ridge, starting at the north end of Vancouver Island, to the Aleutian subduction zone. Along this fault, the Pacific plate is moving northwestward relative to the North American plate at an approximate rate of 16.4 feet per 100 years (5 cm/year). This is what has happened in the Sierra Nevada of central and southern California, as represented by the granite-type rocks of Half Dome within Yosemite National Park shown on the California state quarter. WrangellSt. The collision of tectonic plates can result in earthquakes, volcanoes, the formation of mountains, and other geological events. Parks in the Cascadia Subduction Zone dramatically display the two distinct mountain ranges the Coast Range just above where the Juan de Fuca Plate begins to subduct, and the volcanic Cascade Range farther inland, where the top of the plate is deeper. The Cascadia Subduction Zone, extending from northern California through western Oregon and Washington to southern British Columbia, is a type of convergent plate boundary. Elias National Park Near their boundary, the plates can lock together for centuries, then suddenly let go as a giant earthquake. Kenai Fjords National Park The line of active volcanoes, from Mt. The Cocos Plate is a tectonic plate beneath the Pacific Ocean off the west coast of Central America. The low region between the two mountain ranges is the Puget Sound area of Washington and the Willamette Valley in Oregon. At 20,625 square miles (53,396 square kilometers), Wrangell St. Elias National Park and Preserve is the largest U. S. national park six times the size of Yellowstone. At transform boundaries lithosphere is neither created nor destroyed. Photo courtesy of Robert J. Lillie. What type of plate boundary is North American and Eurasian Plates? They contain explosive volcanoes formed as fluids rise from the top of the subducting plate and generate magma as they melt their way to the surface. But if the lava spills out from beneath the ocean, it encounters cold water and hardens quickly as a pile of pillows. Some transform faults connect continental parts of plates. A forearc basin develops in the low area between the two mountain ranges. What caused the Chile earthquake of 1960? Hood in Oregon, Mt. Cocos Tectonic Plate Many rift valleys are part of " triple junctions," a type of divergent boundary where three tectonic plates meet at about 120 angles. Listing total number of features into an ArcGIS Online feature pop-up, Convergent boundaries: where two plates are colliding. The Philippine Sea plate is tectonically unusual in that almost all the boundaries are convergent. Before we talk about processes at plate boundaries, its important to point out that there are never gaps between plates. Credit: Photo Courtesy of Robert J. Lillie. The Philippine Sea Plate. Wrangell (left) and Mt. The original composite volcano was about 7,000 feet (2,000 meters) high, but lost about 2,500 feet (750 meters) of its height. St. Helens in 1980. The map shows the major tectonic plates that compose Earth's crust and upper mantle Arrows indicate direction of plate movement and the size of the arrows indicate rate of movement. An ancient volcano, Mt. About 200 million years ago a large tectonic plate (called the Farallon Plate) started to subduct beneath the western edge of North America. The addition of water to the hot mantle lowers the rockss melting point and leads to the formation of magma (flux melting) (Figure \(\PageIndex{6}\)). This plate is moving north east towards the Arabia and Eurasia plates. Pangea, which existed from about 350 to 200 Ma, was not the first supercontinent. With continued uplift and erosion, most of the volcanic material would erode.
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