what type of plate boundary caused the 1964 alaska earthquake

Plate Tectonics and Our National ParksSite Index, Plate TectonicsThe Unifying Theory of Geology, Tectonic Settings of NPS SitesMaster List. Geological surveys taken immediately afterward showed parts of the Alaskan coast sank up to eight feet, other parts rose up to 38 feet and much of the coast moved 50 feet towards the ocean. The 1964 Alaska Earthquake and Tsunami lecture by George Plafker, USGS Geologist Emeritus. Copalis River, Washington Trees along the Washington coast were killed by salt-water invasion when the land suddenly dropped during the last great Cascadia Subduction Zone earthquake . When the plates finally give and slip due to the increased pressure, energy is released as seismic waves, causing the ground to shake. The movements of the plates help shape the geological features of our planet. View from the playground of the Government Hill School in Anchorage, showing damage from the 1964 earthquake. As the two tectonic plates converge, friction between them causes coupling of the plates on locked patches of the fault (yellow line, part A). Sometimes the molten rock rises to the surface, through the continent, forming a line of volcanoes. Indeed, like ripples in a pond, a tsunami travels outward in all directions. Channel Islands National Park includes five islands that are the tops of a mostly-submerged portion of the Transverse Ranges. What Can the Ocean Floor Tell Us About Tsunamis? Volcanic rocks at Pinnacles National Park were displaced about 190 miles (305 kilometers), while granitic rocks of Point Reyes National Seashore have moved about 310 miles (500 kilometers). The friction between these massive plates means they dont move fast. Sign up for the Academys monthly newsletter and get a promo code for 10% off at our online retail store. The San Andreas Fault is one of the best examples of lateral plate motion. From Montague Island, the faults and related belt of maximum uplift may extend southwestward on the Continental Shelf to the vicinity of the Kodiak group of islands. The plates move towards one another and this movement can cause earthquakes. Plate Tectonics and Our National Parks (2020), Text and Illustrations by Robert J. Lillie, Emeritus Professor of Geosciences, Oregon State University [E-mail]. Earths big breakup. Science News for Students. A transform plate boundary developed where the Pacific Plate was in contact with the North American Plate and the volcanism ceased in central California. The U.S. Army Corps of Engineers spent about $110 million dollars repairing infrastructure, rebuilding communities, and clearing debris. At this boundary, the Pacific Plate slides beneath the North American Plate, causing the majority of Alaska's earthquakes, including the 1964 earthquake. In Mexico, a combinatiion of divergent and transform plate boundary motion is opening the Gulf of California, causing the Baja Peninsula to separate from the rest of Mexico. Over time, the San Andreas transform plate boundary has grown longer as the Farallon Plate split into two separate platesthe Juan de Fuca Plate on the north, and the Cocos Plate on the south. IRIS video directed by Robert F. Butler explaining the science behind the earthquake. That raised rock runs from the right foreground to the left background. 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/. Earthquakes and tsunamis can happen along any coastline, at any time of the year, but Alaska is particularly prone to them because it sits on the convergence of two tectonic platesthe Pacific Plate and the North American Plate. Tectonics of the March 27, 1964 Alaska Earthquake Hes a research geologist with USGS and its Alaska coordinator of earthquake hazards research. Society for Science & the Public 20002023. Document ID 19990116704 Document Type Other Find History on Facebook (Opens in a new window), Find History on Twitter (Opens in a new window), Find History on YouTube (Opens in a new window), Find History on Instagram (Opens in a new window), Find History on TikTok (Opens in a new window), Education Images/Universal Images Group/Getty Images, Department of Homeland Security & Emergency Management, https://www.history.com/topics/natural-disasters-and-environment/1964-alaska-earthquake. IRIS webpage dedicated to George Plafker, a USGS field geologist noted for his studies of subduction-zone and backarc thrust earthquakes. Finally, the transform boundary, that the San Andreas . The Transverse Ranges north and east of Los Angeles are so named because they trend in an east-west direction, contrary to the northwest-southeast orientation typical of other ranges along the San Andreas transform plate boundary. USGS published the results of investigations of the Alaska earthquake of March 27, 1964 in a series of six Professional Papers. USGS Earthquake Hazards Program.Turnagain Heights Landslide, Anchorage Alaska. Warping resulted in permanent tilt of larger lake basins and temporary reductions in discharge of some major rivers. The quake also led to significant scientific breakthroughs in subduction earthquakes and how to minimize their destruction. A broad earthquake-monitoring system was created to gather data and help seismologists predict future earthquakes and their potential damage. The demolished towns of Valdez and Chenega were rebuilt on higher ground, but not everyone was prudent about rebuilding on earthquake-prone land. Ground failures are an effect of seismic activity in which the ground becomes very soft and acts like liquid, causing landslides, spreading, and settling. The Pacific Plate slides north-northwestward past the North American Plate along the San Andreas Transform Plate Boundary. Feb. 13, 2013. Plafker spent most of the summer in Alaska researching and documenting the earthquake. 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. The April 1933 M6.9 earthquake, which caused considerable damage in Anchorage, appears to have occurred on such . Register to access: Already Registered? 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. As the ground fractured, the trunk experienced extreme tension and eventually split. Do earthquakes occur at divergent plate boundaries? It turned out that the ramps shape was very, very significant. They tend to subtly creep along. An examination of the 1964 Alaska Good Friday Earthquake from a (pre- plate tectonics theory) geological point of view. to A.D. 2022, U.S. Drought: Weekly Report for April 25, 2023, U.S. Drought: Weekly Report for April 18, 2023, U.S. Drought: Weekly Report for April 11, 2023. Scientists are still working out many details of plate tectonics. U.S. Geological Survey Professional Paper 1527, Earthquakes - General Interest Publication - USGS At spreading zones, molten rock rises, pushing two plates . Maximum indicated uplift in the Alaska and Aleutian Ranges to the north of the zone of subsidence was l feet. Most earthquakes occur at the boundaries where the plates meet. All rights reserved. Learn more about UAs notice of web accessibility. It was the largest U.S. earthquake ever recorded, and a turning point in earth science. A documentary chronicling the first 72 hours after the 1964 Alaska Earthquake and the response to the disaster by the United States Office of Civil Defense, U.S. Military, and local, state, and federal officials. As the plates collide, the oceanic plate is forced beneath the continental plate. That is where the plates push into, against or away from each other. Tectonic plates constantly push against each other. In 1964, plate tectonics still was just an emerging if unproven concept. July 6, 2011. Most plates (like the North American one) span both land and seafloor regions. Global historical tsunami data, including more information about the Great Alaska Earthquake, are available via interactive maps and a variety of web services. The damage was caused entirely by the shifting of ground along the fracture, USGS concluded. How do earthquakes occur at convergent plate boundaries? Their thickness ranges from 80 to 200 kilometers (50 to 124 miles). The .gov means its official. Transform Plate Boundaries - Geology (U.S - National Park Service By recording the size, direction and arrival times of the different seismic waves from a quake, seismographs help pinpoint its size and epicenter. S. Ornes. The map shows the epicenter of the 1964 Alaska Earthquake (red star), caused when the Pacific Plate lurched northward underneath the North American Plate. First posted September 10, 2012 Revised August 8, 2013, For additional information: The granite rocks in the foreground are similar to those found in Yosemite National Park in the Sierra Nevada Mountains. The 1964 Great Alaska Quake caused several downtown areas of Anchorage to collapse. These unleashed more tsunamis. Look at your fingernails and watch them grow. The earthquake lasted approximately 4.5 minutes and is the most powerful recorded earthquake in U.S. history. What causes earthquakes? - British Geological Survey In addition to local tsunamis caused by underground landslides, the earthquake triggered an enormous tectonic tidal wave. This can lead to the formation of huge, high mountain ranges such as the Himalayas. mantle The thick layer of the Earth beneath the crust. The motion on the north is not pure transform; there is some convergence that contributes to uplift of the topography. The earthquake must be a shallow marine event that displaces the seafloor. S. Ornes. Californias sheared-up landscape and earthquake hazards reflect the movement of the Pacific Plate past the edge of North America along a transform plate boundary that extends from the Mexican border to north of San Francisco. You'll be happy you did. W.R. Hansen/ USGS, 1964 Alaska quake files. . This 3-panel image shows a simplified representation of a tsunami-generating earthquake cycle on the Alaska-Aleutian Megathrust. The divergent boundary occurs when two tectonic plates move away from each other. Hes a geophysicist with the USGS who recently co-authored a study looking back at the 1964 earthquake. Letters in ovals are abbreviations for NPS sites listed above. This sudden displacement of the ocean floor, along with earthquake-induced landslides, generated massive local tsunamis that resulted in 70 percent of the fatalities in southern Alaska. The average movement of the Pacific Plate past the North American Plate in California is about 2 inches (5 centimeters) per year. Seafloor topography map source: Global sea floor topography from satellite and ship depth soundings, 1997, by W. H. F. Smith and D. T. Sandwell, Science, v. 277, p. 1956-1962. They recalled seeing asphalt roads rise and fall like waves and the ground opening and closing before them, water shooting up through the ensuing cracks. Alaska's continental shelf and North American plate rose over 9 meters during the earthquake. tsunami One or many long, high sea waves caused by an earthquake, submarine landslide or other disturbance. Aftershocks from the quake continued for three weeks. Along other, divergent boundaries, plates move away from each other. Transform boundaries are places where plates slide sideways past each other. The tsunami, which caused massive property damage in Washington, Oregon and California, also claimed four lives in Oregon and 12 in California. , Divergent boundaries where two plates are moving apart. Excerpt from the TV show The Big Picture produced by the US Army in 1966 about the Alaska Earthquake and its tragic effects. This post is part of Exploring Earthquakes, a rich collection of resources co-presented by the California Academy of Sciences and KQED. It caused extensive damage to the city, including fires that lasted for several days, and killed an estimated 3,000 people. PDF The 1964 Great Alaska Earthquake and TsunamisA Modern - USGS On This Day: Great Alaska Earthquake and Tsunami Modified from Earth: Portrait of a Planet, by S. Marshak, 2001, W. W. Norton & Comp., New York. Here, frozen ground holding the roots of this tree, in Anchorage, split apart during a landslide. A divergent boundary occurs when two tectonic plates move away from each other. The tidal wave had diminished by the time it hit Hawaii and Japan, causing little damage. This subduction zone landscape was later plucked from the edge of the North American Plate and transported nearly 200 miles northwestward along the San Andreas Fault. The invention of new tools and faster data processing have drastically improved NOAAs ability to warn the public of tsunamis and to forecast their wave heights. The magnitude 7.8 San Francisco Earthquake struck the morning of April 18, 1906.

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