what type of plate boundary caused the 1964 alaska earthquake

The plate boundary is a broad zone of deformation with a width of about 60 miles (100 kilometers). 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 duration of strain accumulation in the epicentral region, as interpreted from the time interval during which the coastal submergence occurred, probably is 9301,360 years. Trenchward velocities are found also for some sites in the Anchorage area. Global historical tsunami data, including more information about the Great Alaska Earthquake, are available via interactive maps and a variety of web services. 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. Two types of tsunami were produced as a result of this massive quake. Houses pulled apart. There are three types of plate boundaries: spreading zones, transform faults, and subduction zones. 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. Along these boundaries, earthquakes are common and magma (molten rock) rises from the Earths mantle to the surface, solidifying to create new oceanic crust. the first to be generally understood by earth scientists as having occurred on a subduction zone interface: the slip was along the gently dipping boundary, or "megathrust fault," between the denser downgoing oceanic plate and the lighter overriding continental plate. Tectonic plates move very slowly relative to each other, typically a few centimetres per year, but this still causes a huge amount of deformation at the plate boundaries, which in turn results in earthquakes. The earthquake had uplifted large sections of seafloor. 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. The earthquake triggered a swell of devastating tsunamis, landslides and submarine. Anchorage house pulled apart as the ground on which it had been anchored opened up, creating a fissure (or graben). This was a great leap forward in resolving key mechanisms of the developing theory of plate tectonics. During the earthquake, its estimated the fault slipped between 30 to 60 feet, an immense shift. Richter scale Modified Mercalli scale the Centigrade scale the moment magnitude scale. lithosphereThe upper layer of Earth, which includes its thin brittle crust and upper mantle. Oral presentations, poster sessions, exhibits, field trips, business meetings and social gatherings all provide participants the opportunity to meet and share with their peers. There are three types of tectonic plate boundaries: Another large-scale feature is a hotspot, where a plate rides over a rising plume of hot mantle, creating a line of volcanoes on top of the plate. The fissure shown here is about 1.5 inches wide. Of the 139 deaths attributed to this event, 124 were directly caused by the tsunamis. The 1964 M9.2 Great Alaska Earthquake, which is still the second largest earthquake ever recorded worldwide, began under Prince William Sound. The valleys are commonly due to erosion along individual fault lines. To view this site, enable JavaScript by changing your browser options and try again. The 1964 Alaska earthquake resulted from rupture along the thrust fault boundary bet- ween the downgoing Pacific Plate and the overriding North American Plate, causing widespread shaking and tectonic defor- mation. 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. Feature labels. This report is presented in Portable Document Format (PDF); the latest version of Adobe Reader or similar software is required to view it. In Alaska, the Pacific plate, relative to the North American plate, moves at a rate of ~5.5+ cm/yr (~2.2+ in/yr). When a fault actually slips, the motion is both sudden and exaggerated. Sometimes a sub-surface cave becomes too weak to support the ground above it. The Ring of Fire also marks the edge of the Pacific Plate. N&SP = National and State Parks But if you see something that doesn't look right, click here to contact us! Southeast of Florida, the Caribbean Plate is sliding east-northeast about 0.8 inches (2 centimeters) per year relative to the North American Plate. This stretch of road had been built partly atop mud from a tidal estuary and other unsecure soils. The control tower at Anchorage International Airport collapsed, killing an air traffic controller. Channel Islands National Park, Santa Monica Mountains National Recreation Area and Joshua Tree National Park are within the Transverse Ranges, a block of crust that rotated as a result of the shearing motion. As the ground fractured, the trunk experienced extreme tension and eventually split. A reverse fault, like the Cascadia subduction zone off the coast of Oregon and Northern California (north of Mendocino California), has relatively deep earthquakeslike the 1964 Alaska earthquake and the 2004 As the plates collide, the oceanic plate is forced beneath the continental plate. The yellow cab of the truck wrapped around the right side of a tree; its wheels around the left side. Some had been up to 24 inches (61 centimeters) in diameter and as much as 101 feet (30.8 meters) above sea level. They have been transported about 300 miles (500 kilometers) in a north-northwestward direction along the transform plate boundary. Continental transform faults play a critical role in accommodating strain along major tectonic plate boundaries. In fact, megathrust events are the largest type of earthquake on the planet, notes Peter Haeussler. Earthquakes at divergent plate boundaries occur as new crust is created and other crust is pushed apart. Listing total number of features into an ArcGIS Online feature pop-up, Convergent boundaries: where two plates are colliding. USC Tsunami Research Group.The Great M9.2 Alaska Earthquake and Tsunami of March 27, 1964. Is earthquake a result of plate tectonics? 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. Ned Rozells personal account of his meeting with George Plafker, one of three USGS Geologists who responded to the Alaska quake a few days after event. Remove unwanted regions from map data QGIS. The grinding action between the plates at a transform plate boundary results in shallow earthquakes, large lateral displacement of rock, and a broad zone of crustal deformation. Sometimes the extraction of groundwater leaves a hole that cannot support the ground above. Point Reyes National Seashore and Golden Gate National Recreation Area are the only two NPS sites that are right on the San Andreas Fault. 1). This causes the crust to crack and form faults where earthquakes occur. It turned out that the ramps shape was very, very significant. That motion was huge, West says. The sequence begins shortly after the last earthquake. The Alaska Earthquake Alliance coordinates earthquake awareness and preparedness activities throughout Alaska. Most of Alaskas mainland felt the magnitude 9.2 earthquake, which wobbled Seattles Space Needle some 1,200 miles away. Enter your e-mail address above. The tidal wave had diminished by the time it hit Hawaii and Japan, causing little damage. Originating off the coast of southern Chile on May 22, 1960, the temblor caused substantial damage and loss of life both in that country andas a result of the tsunamis that it generatedin distant Pacific coastal areas. The 1964 Alaska Earthquake and Tsunami lecture by George Plafker, USGS Geologist Emeritus. The transform plate boundary between the Pacific and North American Plates in western California formed fairly recently. These tectonic plates move gradually, bumping and grinding against each other. 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. Landslide and slumping effects in the Turnagain Heights area, Anchorage, Alaska, caused by the March 28, 1964, earthquake. aftershock One or more smaller earthquakes that often follow a major earthquake. There, in California, that motion causes earthquakes along the infamous San Andreas Fault. USGS concluded that the earthquake did not shake down much of the snowpack. They occur where plates are subducting, spreading, slipping, or colliding. The publication, as well as. 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. earthquake A sudden and sometimes violent shaking of the ground, sometimes causing great destruction, as a result of movements within Earths crust or of volcanic action. Layers of ocean sediment were squeezed and contorted as they were caught in the vise of the converging plates at the ancient subduction zone. Uplift that averages 6 feet over broad areas occurred mainly along the coast of the Gulf of Alaska, on the adjacent Continental Shelf, and probably on the continental slope. They form due to north-south compression where the San Andreas Fault bends to an east-west orientation. On the east, the North American Plate is subducting westward, forming volcanoes of the Lesser Antilles Island Arc. There are three main types of plate boundaries: There are four types of boundaries between tectonic plates that are defined by the movement of the plates: divergent and convergent boundaries, transform fault boundaries, and plate boundary zones. Afterward, the roots daily bathing for hours each day in salt water killed these trees. Warping resulted in permanent tilt of larger lake basins and temporary reductions in discharge of some major rivers. Although the school was destroyed, the nearby water tower was undamaged. The primary fault, or zone of faults, along which the earthquake occurred is not exposed at the surface on land. The compressed and uplifted region includes the Santa Monica Mountains north of Los Angeles as well as the Channel Islands south of Santa Barbara. As the plates move past each other, they sometimes get caught and pressure builds up. The seismographs recorded these aftershocks as well. Pacific Plate motion also creates volcanoes as rock melted by the sinking plate rises to the surface. The foreground shows a ditch (or graben) that opened up roughly 12 feet (or around 3.7 meters) deep. USGS circular published one month after the earthquake by Arthur Grantz, George Plafker, and Reuben Kachadoorian detailing their scientific investigations of the quake. That doesnt seem like much, but over time it adds up. You should receive your promo code shortly. The fault is marked by a 10- to 15-foot (3 to 4.6 meter) uplifted portion of bedrock. The .gov means its official. The land that was uplifted and sometimes dropped by the Great Alaskan Quake also fits with the plate-tectonics model. 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. The San Andreas Fault and Queen Charlotte Fault are transform plate boundaries developing where the Pacific Plate moves northward past the North American Plate. Scientists learned that at the point where the North American Plate overrode the Pacific Plate, it descended into a subduction zone. In Alaska, that plate dives under the North American Plate. Ideas for using videos, articles, and infographics about earthquakes in the classroom. tectonic plates The gigantic slabs some spanning thousands of kilometers (or miles) across that make up Earths outer layer. 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.. seismology The science concerned with earthquakes and related phenomena. Parks in western California contain blocks of crust that have moved great distances north-northwestward along the San Andreas Fault. When the earthquake struck, seismic waves caused soil liquefaction and a portion of the delta slumped into Port Valdez, taking much of the ports resources, living and otherwise, with it. In Alaska, more than 50 volcanoes have erupted over the last 250 years. (The lithosphere is Earths outer solid layer. Map showing plate boundaries that were active during the 1964 Great Quake. 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. Which of the following measures an earthquake's intensity based on the observed effects on people and structures? Coastal trees, here near the Port of Valdez, were snapped off. S. Perkins. The earthquake lasted approximately 4.5 minutes and is the most powerful recorded earthquake in U.S. history. A broad earthquake-monitoring system was created to gather data and help seismologists predict future earthquakes and their potential damage. At still others, known as transform boundaries, plates slide past each other. The Pacific Plate slides north-northwestward past the North American Plate along the San Andreas Transform Plate Boundary. 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! Strong, destructive earthquakes can accompany a rapid, several-meter uplift of bedrock along subduction zones. The largest tsunami wave of the 1964 Alaska Earthquake measured over 200 feet in height and was recorded at Shoup Bay near the Valdez inlet. The site is secure. When the plates finally give and slip due to the increased pressure, energy is released as seismic waves, causing the ground to shake. 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. 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 uaf-aec@alaska.edu or by phone at 907-474-7320. Which plates caused the most earthquakes? Channel Islands National Park includes five islands that are the tops of a mostly-submerged portion of the Transverse Ranges. 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. Alaskans are familiar with earthquakes. Parks in the Sierra Nevada, including Yosemite, Kings Canyon, and Sequoia national parks, contain granite-type rocks that cooled within magma chambers beneath ancient subduction zone volcanoes.
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