OfficeEarthquake Science Center Learn more about UAs notice of web accessibility. Transform boundaries occur on the north and south sides of the Caribbean Plate. Ideas for using videos, articles, and infographics about earthquakes in the classroom. Plate boundaries. It is relatively cold and brittle. HISTORY.com works with a wide range of writers and editors to create accurate and informative content. In the Turnagain Heights area of Anchorage, soil liquefaction (when the ground behaves like a liquid) triggered a landslide which moved parts of a suburban bluff 2,000 feet into the bay, taking up to 75 homes with it. Was the 1964 Alaska earthquake was the first time earthquakes were linked to plate tectonics? USGS.The 1964 Great Alaska Earthquake. Produced under a Cooperative Agreement for earth science education between the National Park Service's Geologic Resources Division and the American Geosciences Institute. Reports of residual water sloshing (seiches) came in from the U.S. Gulf Coast and as far away as Australia. No Alaskan who survived would ever forget this day. It was the largest U.S. earthquake ever recorded, and a turning point in earth science. 345 Middlefield Road, MS 977 USGS concluded that the earthquake did not shake down much of the snowpack. In some cases, however, a convergent plate boundary can result in one tectonic plate diving underneath another. Before the event, the sidewalk (left) had been as high as the street (far right). And it moved parts of the Alaskan coast 15 meters (50 feet) toward the sea. When two tectonic plates slide past each other, the place where they meet is a transform or lateral fault. Seismic waves caused the earth to ring like a bell.. seismograph (also known as aseismometer) An instrument that detects and measures tremors (known as seismic waves) as they pass through Earth. NOAA Natural Hazards Image Database. S. Ornes. View from the playground of the Government Hill School in Anchorage, showing damage from the 1964 earthquake. The town of Valdez was originally built on sand and gravel. The San Andreas Fault that runs through much of California is an enormous transform plate boundary. The earthquakes that occur along these zones, called spreading centers, are relatively small. You'll be happy you did. The sedimentary and metamorphic rocks across the fault line are similar to those found in Redwood National and State Parks on the North Coast of California. The tidal wave had diminished by the time it hit Hawaii and Japan, causing little damage. It effortlessly toppled telephone poles, buckled railroad tracks, split roads in half, uprooted buildings, cars and docks and tore homes apart. Ground subsidence due to the earthquake created a huge, deep ditch (a graben) that ran through the yard and under this house in Anchorage. Faults are fractures in Earths crust where movement has occurred. The Alaska Earthquake Alliance coordinates earthquake awareness and preparedness activities throughout Alaska. They still had many questions to answer. Like many of the rocks that are caught up in the zone of transform motion between the Pacific and North American plates, the rocks at Channel Islands National Park were deformed as part of the accretionary wedge during earlier subduction of the Farallon Plate. The Sierra Nevada are the eroded remnants of the volcanic arc developed when the Farallon Plate subducted beneath the continent. Every century or so a large earthquake is necessary to release stress accumulated along large segments of the San Andreas Fault that lock rather than slip smoothly. These spruce trees had been growing along the shores of Resurrection Bay in southern Alaska. Quake leaves destruction, fear. Science News for Students. magazine, are published by the Society for Science, a nonprofit 501(c)(3) membership organization dedicated to public engagement in scientific research and education. Some of the plates have ocean water above them. A massive tidal wave crushed the small, coastal village of Chenega four minutes after the tremors subsidedthe town lost a third of its population. The March 27, 1964, earthquake was accomp anied by crustal deformation-including warping, horizontal distortion, and faulting-over probably more than 110,000 square miles of land and sea bottom in south-central Alaska. Microplates are smaller fragments of tectonic plates that appear in plate boundary zones. Produced under a Cooperative Agreement for earth science education between the National Park Service's Geologic Resources Division and the American Geosciences Institute. Big quake, little destruction. Science News for Students. NM = National Monument The tsunamis created by the earthquake reached land within a few minutes of the ground shaking and engulfed some areas as much as 170 feet above sea level. The San Andreas Fault is just one of several faults that accommodate the transform motion between the Pacific and North American 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. Sometimes a sub-surface cave becomes too weak to support the ground above it. Some start and then stop, only to start again much later. The plate motion has plucked the rocks from their original position and moved them more than 300 miles north-northwestward to their current position at Point Reyes. Which type of boundaries can produce earthquakes at which produces the largest earthquakes? The Earthquake Trail at Point Reyes weaves back and forth across the fault line. When a fault actually slips, the motion is both sudden and exaggerated. NP = National Park (en Espaol). People who work in this field are known as seismologists. This uplift attained a measured maximum on land of 38 feet in a northwest-trending narrow belt less than 10 miles wide that is exposed on Montague Island in southwestern Prince William Sound. Listing total number of features into an ArcGIS Online feature pop-up, Convergent boundaries: where two plates are colliding. Tsunamis caused loss of life, extensive flooding, and damaged harbors along the North American Pacific Northwest coast. Fracking wastes and quakes. Science News for Students. 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. Imagine traveling from New Zealand clockwise around the rim of the Pacific Ocean, all the way to the tip of South America. Produced by Creative Arts Studio in 1964 for the USGS. An official website of the United States government. Continental transform faults play a critical role in accommodating strain along major tectonic plate boundaries. But its interesting to note that this region is so heavily populated because of the same tectonic forces that sometimes shake it up with such violent consequences during earthquakes. Slight uplift inland from the major zones of deformation presumably was related to elastic strain changes resulting from the overthrusting; however, the data are insufficient to permit conclusions regarding its cause. The lithosphere is relatively rigid and is broken into slowly moving tectonic plates. Tomales Bay. This post is part of Exploring Earthquakes, a rich collection of resources co-presented by the California Academy of Sciences and KQED. There are three types of plate boundaries: spreading zones, transform faults, and subduction zones. Plafker, G., 1969, Tectonics of the March 27, 1964 Alaska earthquake: U.S. Geological Survey Professional Paper 543I, 74 p., 2 sheets, scales 1:2,000,000 and 1:500,000, https://pubs.usgs.gov/pp/0543i/. S. Ornes. The belt of seismic activity and major zones of tectonic deformation associated with the 1964 earthquake, to a large extent, lie between and parallel to the Aleutian Volcanic Arc and the Aleutian Trench, and are probably genetically related to the arc. In fact, megathrust events are the largest type of earthquake on the planet, notes Peter Haeussler. The earthquake must be a shallow marine event that displaces the seafloor. (The lithosphere is Earths outer solid layer. Thousands of earthquakes over millions of years have built this landscape not only along the major fault linethe San Andreas Faultbut also on other faults within the broad zone of shearing between the Pacific and North American plates. Another form of convergent boundary is a collision where two continental plates meet head-on. Regional uplift and subsidence occurred mainly in two nearly parallel elongate zones, together about 600 miles long and as much as 250 miles wide, that lie along the continental margin. Some had been up to 24 inches (61 centimeters) in diameter and as much as 101 feet (30.8 meters) above sea level. These cracks generally ran at high angles to the faults and could run a few hundred feet and span 6 inches (15 centimeters). The devastating 9.2 magnitude earthquake and subsequent tsunamis ravaged coastal communities and took over 139 lives. Remove unwanted regions from map data QGIS. An interplate earthquake is an earthquake that occurs at the boundary between two tectonic plates.Earthquakes of this type account for more than 90 percent of the total seismic energy released around the world. Scientists learned a lot from data gathered after the 1964 Alaskan earthquake and put the knowledge to good use. When the ground dropped 3 feet, the trees shallow roots ended up in the tidal zone. Subduction zones occur when one or both of the tectonic plates are composed of oceanic crust. At 5:36 p.m. on March 27, 1964Good Fridaythe earth trembled just as many Alaskans were sitting down to dinner. The data helped engineers develop earthquake-resistant structures to limit future casualties and property damage. Enter your e-mail address above. transform boundaries The edges of two neighboring tectonic plates that are sliding against one another. Earthquakes occur along fault lines, cracks in Earths crust where tectonic plates meet. About 80% of earthquakes occur where plates are pushed together, called convergent boundaries. Molten rock from the mantle erupts along the opening, forming new crust. By midnight, 131 people were dead. As the plates grind together, they get stuck and pressure builds up. Two types of tsunami were produced as a result of this massive quake. S. Ornes. An animation that describes earthquakes along the Aleutian subduction zone, one of the most seismically active in the world, and the Queen Charlotte Transform Fault. This led to the establishment of the Pacific Tsunami Warning Center (originally called the West Coast/Alaska Tsunami Warning Center) to alert people when a widespread tsunami is possible. The 1964 Alaska Earthquake taught coastal citizens to run for higher ground at the first sign of strong tremors. Earthquakes are the result of sudden movement along faults within the Earth. The broad zone of shearing at a transform plate boundary includes masses of rock displaced tens to hundreds of miles, shallow earthquakes, and a landscape consisting of long ridges separated by narrow valleys. Hes a geophysicist with the USGS who recently co-authored a study looking back at the 1964 earthquake. UA is committed to providing accessible websites. A broad earthquake-monitoring system was created to gather data and help seismologists predict future earthquakes and their potential damage. briefly recounts the events of March 27, 1964 and explains the scientific and societal importance of the earthquake. The earthquake was accompanied by vertical displacement over an area of about 520,000 square kilometers. To view this site, enable JavaScript by changing your browser options and try again. In places like Hawaii and Yellowstone, a plate rides over a rising plume of hot mantle, causing earthquakes and a chain of volcanoes. It was the first global seismic network, West tells Science News for Students. Our plate boundary comprises ~2,500 miles of the circum-Pacific "Ring of Fire" where ongoing subduction gives rise to arcs of active volcanoes and the largest earthquakes in the world. What caused the Alaska earthquake in 1964? The Australian plate is a continental plate and the Pacific plate is an oceanic plate. Like a jigsaw puzzle, Earths lithosphere is divided into interlocking pieces, called plates. Photo courtesy of Robert J. Lillie. Layers of ocean sediment were squeezed and contorted as they were caught in the vise of the converging plates at the ancient subduction zone. The Aleutian Trench (or Aleutian Trough) is an oceanic trench along a convergent plate boundary which runs along the southern coastline of Alaska and the Aleutian islands.The trench extends for 3,400 kilometres (2,100 mi) from a triple junction in the west with the Ulakhan Fault and the northern end of the Kuril-Kamchatka Trench, to a junction with the northern end of the Queen Charlotte . This can lead to the formation of huge, high mountain ranges such as the Himalayas. The 1964 M9.2 Great Alaska Earthquake, which is still the second largest earthquake ever recorded worldwide, began under Prince William Sound. Systematic horizontal movements of the land relative to bodies of confined or semiconfined water may have caused unexplained short-period wavessome of which were highly destructiveobserved during or immediately after the earthquake at certain coastal localities and in Kenai Lake. Also just like a rug, the land spreads out as it flattens. They knew earthquakes develop when shifts occur along underground fractures, called faults. Point Reyes National Seashore and Joshua Tree National Park have granitic magma-chamber rocks of the eroded arc, and Pinnacles National Park preserves volcanic rocks. Many transform boundaries are found on the sea floor, where they connect segments of diverging mid-ocean ridges. Plate Tectonics and Our National ParksSite Index, Plate TectonicsThe Unifying Theory of Geology, Tectonic Settings of NPS SitesMaster List. Which type of boundaries can produce earthquakes? Page Contact Information: Contact USGS Southeast of Florida, the Caribbean Plate is sliding east-northeast about 0.8 inches (2 centimeters) per year relative to the North American Plate. According to the United States Geological Survey, The 1964 earthquake was giant because of the large area of the fault that slipped during the earthquake and the large amount of slip, or relative motion, between opposite sides of the earthquake fault.. The movements of the plates help shape the geological features of our planet. This pattern has since been seen at other subduction zones. Comparable horizontal movements are presumed to have affected those parts of the major zones of uplift and subsidence for which retriangulation data are unavailable. This resulted in a line of volcanoes stretching all the way from what is now Alaska to Central America. Coastal forests plunged below sea level and were destroyed by salt water. When a continental plate meets an oceanic plate, the thinner, denser, and more flexible oceanic plate sinks beneath the thicker, more rigid continental plate. One of many trees damaged by quake impacts. The friction between these massive plates means they dont move fast. They have been transported about 300 miles (500 kilometers) in a north-northwestward direction along the transform plate boundary. But Alaskas 1964 Great Quake led to a huge leap in their understanding. The epicenter is that X-marks-the-spot site where the tremors commenced. Point Reyes National Seashore, California. An offset fence line reveals the 16 feet (5 meters) of lateral ground breakage that occured as the San Andreas Fault suddenly let loose during the 1906 San Francisco Earthquake. The quake also led to significant scientific breakthroughs in subduction earthquakes and how to minimize their destruction. What kind of plate boundary causes mountains to form? The Great Rift Valley in Africa, the Red Sea and the Gulf of Aden all formed as a result of divergent plate motion. Oreo cookies are a fun way to demonstrate the three types of plate boundaries and a hotspot. These instruments detect and record earthquakes. At still others, known as transform boundaries, plates slide past each other. The earthquake rupture started approximately 25 km beneath the surface, with its epicenter about 6 miles (10 km) east of the mouth of College Fiord, 56 miles (90 km) west of Valdez and 75 miles (120 km) east of Anchorage. It extends across the two zones from the chain of active volcanoes in the Aleutian Range and Wrangell Mountains probably to the Aleutian Trench axis. The Great Alaskan Earthquake was a magnitude-9.2 event. Society for Science & the Public 20002023. Now, a full half-century after Alaskas gigantic quake, geologists are still feeling its effects. U.S. Geological Survey The seismographs recorded these aftershocks as well. The landscapes of our national parks, as well as geologic hazards such as earthquakes and volcanic eruptions, are due to the movement of the large plates of Earths outer shell. Alaskas continental shelf and North American plate rose over 9 meters during the earthquake. They also forecasthow large any resulting tsunami will be as it crosses the ocean. Much to the dismay of some earthquake experts, luxury homes were rebuilt on areas most likely to experience earthquake damage, including on top of the ruins in Turnagain Heights. Through very complete mapping of vertical deformation and faulting and the application of tectonics, he was first to propose in 1965 that the source of the 1964 Alaska earthquake was a low-angle thrust fault. In Alaska, the flattening caused some of the affected land to drop. Though this hazardous event developed the moniker of the Great Alaska Earthquake, it was actually the ensuing tsunamis that did the greatest damage and took the most lives. All Rights Reserved. Sometimes the molten rock rises to the surface, through the continent, forming a line of volcanoes. Modified from Earth: Portrait of a Planet, by S. Marshak, 2001, W. W. Norton & Comp., New York. All rights reserved. Eyewitnesses described hearing a crunching, grinding noise as the earth shook. That will give you an idea of how fast the plates move relative to one anotherabout a fraction of an inch to a few inches per year! They were scouting for patterns. Perhaps nowhere on Earth is such a landscape more dramatically displayed than along the San Andreas Fault in western California. The violent shaking led to water, sewer and gas line breaks and widespread telephone and electrical failures. Question: What type of tectonic plate boundary exists along the edge of the North American plate near the coast of Northern California, Oregon, and Washington? in that one quake, it was the first time that you could actually see plate motion in action.
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