what type of plate boundary caused the 1964 alaska earthquake

The town of Valdez was originally built on sand and gravel. That motion was huge, West says. First posted September 10, 2012 Revised August 8, 2013, For additional information: Imagine that your left hand is the undeformed Pacific Plate, your right hand the intact North American Plate. Transoceanic tsunami waves swept across the Pacific and reached as far away as Hawaii and Japan. For western California, each slipping card face would be a fault surface. Sometimes tectonic activity just shifts large portions of Earths surface, thrusting upward some portions along a fault. , Divergent boundaries where two plates are moving apart. Due to the long duration of the earthquake, catastrophic ground failures occurred. The delta slump triggered a local tsunami which destroyed almost anything left standing and ruptured the Union Oil Companys oil tanks, igniting a massive fire. This was the Big One. The earthquake ruptured a large portion of the San Andreas Fault, including land that is now Point Reyes National Seashore and Golden Gate National Recreation Area. 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. . Policies and Notices, U.S. Department of the Interior | Document ID 19990116704 Document Type Other Explains how Yakutat terrane accretion drives mountain building and crustal fault earthquakes like the 2002 M7.9 Denali Earthquake. aftershock One or more smaller earthquakes that often follow a major earthquake. Where tectonic plates slip horizontally past one another, lithosphere is neither created nor destroyed. The 1964 earthquake in Anchorage, Alaska occurred as a result of an oceanic plate sinking under a continental or land plate. Some had been up to 24 inches (61 centimeters) in diameter and as much as 101 feet (30.8 meters) above sea level. Often it is the older and colder plate that is denser and subducts beneath the younger and warmer plate. When the plates finally give and slip due to the increased pressure, energy is released as seismic waves, causing the ground to shake. Richter scale Modified Mercalli scale the Centigrade scale the moment magnitude scale. They were lifted out of the ocean as part of the accretionary wedge of an ancient subduction zone. Instead, blocks of crust are torn apart in a broad zone of shearing between the two plates. 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 Australian plate is a continental plate and the Pacific plate is an oceanic plate. Summary of the earthquakes cause and effects from the Alaska Earthquake Information Center. The broad zone of transform motion between the Pacific and North American plates formed numerous slivers of mountain ranges with narrow valleys in between. 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. Hes a geophysicist with the USGS who recently co-authored a study looking back at the 1964 earthquake. Typically, a convergent plate boundarysuch as the one between the Indian Plate and the Eurasian Plateforms towering mountain ranges, like the Himalaya, as Earths crust is crumpled and pushed upward. The convergent boundary happens when two plates slide toward each other to form a subduction zone or a continental collision. A plate boundary is a three-dimensional surface or zone across which there is a significant change in the velocity (speed or direction) of motion of one lithospheric plate relative to the adjacent lithospheric plate. They have been transported about 300 miles (500 kilometers) in a north-northwestward direction along the transform plate boundary. Sometimes the valleys are partially filled with water, as at Point Reyes National Seashore, where Tomales Bay and Olema Valley follow the main trace of the San Andreas Fault. Letters in ovals are abbreviations for NPS sites listed above. Such movement on the faults is generally a response to long-term deformation and the buildup of stress. The April 1933 M6.9 earthquake, which caused considerable damage in Anchorage, appears to have occurred on such . About 80% of earthquakes occur where plates are pushed together, called convergent boundaries. What Caused The Most Deaths In The Great Alaska Earthquake Of 1964? View from the playground of the Government Hill School in Anchorage, showing damage from the 1964 earthquake. These films were shot by amateur and professional cameramen in the hours and days following the earthquake at locations such as Anchorage, Kodiak, Seward, Valdez, Chenega, Afognak. All rights reserved. When oceanic and continental plates meet, the denser oceanic plate moves under the less dense continental plate. An expanded version (11 min) is also available: 1964 Quake: The Alaska Earthquake This opinion piece by USGS geologist Peter Haeussler, et al. plate convergenceplate convergence: where the Pacific Plate is being overridden by the North American Plate, it descends, or subducts, into the Earths mantle along the Aleutian Trench. Answers for geologist, scientists, spacecraft operators. seismograph (also known as aseismometer) An instrument that detects and measures tremors (known as seismic waves) as they pass through Earth. Thursday NightLife (21+): 6 10 pm. (The lithosphere is Earths outer solid layer. Modified from Earth: Portrait of a Planet, by S. Marshak, 2001, W. W. Norton & Comp., New York. Thats a type of convergent plate boundary where one plate dives beneath another. Reports of residual water sloshing (seiches) came in from the U.S. Gulf Coast and as far away as Australia. Earthquakes can strike any location at any time, but history shows they occur in the same general patterns year after year, principally in three large zones of the earth: 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 . convergent plate boundaries divergent plate boundaries transform plate . Map showing ground motion and shaking intensity based on instrumental measurements of shaking along with information about local geology and the earthquakes location and magnitude. Identifying port numbers for ArcGIS Online Basemap? An effective tsunami warning system relies on the free and open exchange and long-term management of global data and science products to mitigate, model, and forecast tsunamis. Evidence for progressive coastal submergence in the deformed region for several centuries preceding the earthquake, in combin1ation with transverse horizontal shortening indicated by the retriangulation data, suggests pre-earthquake strain directed at a gentle angle downward beneath the arc. Most earthquakes at divergent plate boundaries occur at mid-ocean ridges where two pieces of oceanic crust are moving away from each other. Sometimes the extraction of groundwater leaves a hole that cannot support the ground above. They occur where plates are subducting, spreading, slipping, or colliding. At still others, known as transform boundaries, plates slide past each other. The fissure shown here is about 1.5 inches wide. Sunday: 11 am 5 pm (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). At an ocean-ocean convergent boundary, one of the plates (oceanic crust and lithospheric mantle) is pushed, or subducted, under the other (Figure 4.6. Remove unwanted regions from map data QGIS. N Pres = National Preserve. Privacy This causes the crust to crack and form faults where earthquakes occur. The site is secure. A divergent boundary occurs when two tectonic plates move away from each other. Some start and then stop, only to start again much later. S. Ornes. convergent boundaries The edges of two neighboring tectonic plates that are colliding into one another. Rocks have been disrupted by shearing and other forces associated with the transform plate motion and, in some instances, transported northward a long distance from where they originally formed. Plafkers team mapped all the changes triggered by the quake that they could find. Oct. 16, 2012. Page Last Modified: Thursday, December 01, 2016, 04:21:41 PM, Download the latest version of Adobe Reader, free of charge. UAF is an AA/EO employer and educational institution and prohibits illegal discrimination against any individual: If you have difficulty accessing the information on this website due to a disability, please contact the web administrator by email at [email protected] or by phone at 907-474-7320. In Alaska, the Pacific plate, relative to the North American plate, moves at a rate of ~5.5+ cm/yr (~2.2+ in/yr). Divergent boundaries - where two plates are moving apart. Then suddenly, it pops open. It was the first time we had physical proof of plate tectonics, concludes Mike West. What is it about an earthquake that causes a tsunami? 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.. S. Ornes. The San Andreas Transform Plate Boundary developed within the past 40 million years as a large portion of the Farallon Plate was subducted and the Pacific Plate made contact with the North American Plate in the California region. Learn about the Great Alaska Earthquake of 1964 in this video adapted from the Valdez Museum & Historical Archive. Download the official NPS app before your next visit, Plate Tectonics and Our National ParksSite Index, Plate TectonicsThe Unifying Theory of Geology, Tectonic Settings of NPS SitesMaster List. April 30, 202323:37:54 AKDT (May 1, 202307:37:54 UTC)61.7528N146.4391W Depth 19.4 miles (31 km), This event has not been reviewed by a seismologist, 2156 Koyukuk Drive, PO Box 757320, Fairbanks, AK 99775. Microplates are smaller fragments of tectonic plates that appear in plate boundary zones. Aftershocks from the quake continued for three weeks. Earth definitely moved with a start during the 1964 quake. Regional vertical deformation generated a train of destructive long-period seismic sea waves in the Gulf of Alaska as well as unique atmospheric and ionospheric disturbances that were recorded at points far distant from Alaska. About 80% of earthquakes occur where plates are pushed together, called convergent boundaries. SSAs 2014 Annual Meeting will provide a stimulating exchange of research on a wide range of topics with colleagues from all over the world. All Rights Reserved. Accessibility 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. At 5:36 p.m., the ground began shaking violently. Do Transform boundaries cause earthquakes? HISTORY.com works with a wide range of writers and editors to create accurate and informative content. This post is part of Exploring Earthquakes, a rich collection of resources co-presented by the California Academy of Sciences and KQED. Retriangulation over roughly 25,000 square miles of the deformed region in and around Prince William Sound shows that vertical movements there were accompanied by horizontal distortion, involving systematic shifts of about 64 feet in a relative seaward direction. Tomales Bay is the surface expression of the San Andreas Fault, seen in the photo below. Most plates (like the North American one) span both land and seafloor regions. This is known as subduction. Tsunami waves can hit with the devastating force of a powerful tornado. NRA = National Recreation Area Why A Leak At The Bottom Of The Pacific Ocean Has Scientists - Forbes The tsunami, which caused massive property damage in Washington, Oregon and California, also claimed four lives in Oregon and 12 in California. The video features USGS geologist George Plafker who, in the 1960s, correctly interpreted the quake as a subduction zone event. Articles with the HISTORY.com Editors byline have been written or edited by the HISTORY.com editors, including Amanda Onion, Missy Sullivan and Matt Mullen. The epicenter of the 1964 quake occurred deep beneath the Chugach Mountains, shown here some time later. Get a new perspective on earthquakes with this rich collection of multimedia resources. At transform boundaries lithosphere is neither created nor destroyed. On the east, the North American Plate is subducting westward, forming volcanoes of the Lesser Antilles Island Arc. Pacific Plate motion also creates volcanoes as rock melted by the sinking plate rises to the surface. When the fault finally slips, its like a rug flattening out. This pattern has since been seen at other subduction zones. Scientists now classify the bumping and grinding between plates in three different ways. The 1964 quake woke up the dormant Hanning Bay fault on Montague Island in Alaskas Prince William Sound. 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. Solved What type of tectonic plate boundary exists along the - Chegg The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely. Sometimes a sub-surface cave becomes too weak to support the ground above it. In central and southern California, for example, the volcanoes have largely eroded away and massive areas of granite from the cooled magma chambers form portions of the Sierra Nevada Mountains, including Yosemite National Park. Plate Tectonics and Our National Parks (2020), Text and Illustrations by Robert J. Lillie, Emeritus Professor of Geosciences, Oregon State University [E-mail]. In bays and inlets, the quake also triggered underwater landslides. Molten rock from the mantle erupts along the opening, forming new crust. 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. Hear a first-person account of the event, watch an animation that illustrates the subduction of the Pacific plate under the North American plate, and observe how Valdez was affected. Downtown Anchorage had the most property damage mainly due to immense landslides, one of which dropped the business district nine feet. But this was no ordinary tremor. You should receive your promo code shortly. In places like Hawaii and Yellowstone, a plate rides over a rising plume of hot mantle, causing earthquakes and a chain of volcanoes. Types of Plate Boundaries - Geology (U.S. National Park Service) Doing some quick math, one can appreciate how dramatically plate-tectonic forces can affect the landscape, even in our lifetimes.

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