The Fairweather fault system in southeast Alaska (over 620 miles long) is the primary strike-slip structure that accommodates ongoing subduction. Plate convergence at the southern margin of the state drives distributed deformation on secondary faults over 400 miles northward into the continental interior.
Why is Alaska so prone to earthquakes?
How long did the Great Alaska earthquake last?
What were the major damage caused by the Anchorage earthquake?
How much damage did the Alaska tsunami cause?
What is NCEI tsunami?
How high did the tsunami in Alaska go?
What towns were hit by the Great Alaska earthquake?
See 4 more
About this website
What type of fault was the great Alaskan earthquake?
The Alaska earthquake was a subduction zone (megathrust) earthquake, caused by an oceanic plate sinking under a continental plate. The fault responsible was the Aleutian Megathrust, a reverse fault caused by a compressional force.
What was significant about the earthquake in Alaska?
It was the largest U.S. earthquake ever recorded, and a turning point in earth science. Learn about the great leaps in research over the past 50 years.
What type of plate boundary caused the Great Alaska Earthquake?
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.
What made the 1964 Alaska earthquake special?
The 1964 Alaska earthquake, the strongest earthquake ever recorded in North America, struck Alaska's Prince William Sound, about 74 miles southeast of Anchorage. Most of Alaska's mainland felt the magnitude 9.2 earthquake, which wobbled Seattle's Space Needle some 1,200 miles away.
What was the worst earthquake in history?
Also known as the Great Chilean earthquake (Spanish: Gran terremoto de Chile), it was the most powerful earthquake ever recorded. The earthquake hit on May 22 in the afternoon (19:11 GMT, 15:11 local time), approximately 100 miles (160 km) off the coast of Chile, parallel to the city of Valdivia.
Is Alaska on a fault line?
The Queen Charlotte-Fairweather fault in southeastern Alaska is analogous to California's San Andreas fault, both in length and type (strike-slip). Both faults form a boundary where two blocks of Earth's crust—the North American and Pacific tectonic plates—slide horizontally past each other in opposite directions.
How many fault lines are in Alaska?
Geologically young displacements have been observed along 24 faults in an area of Alaska of approximately 624,000 km2.
What was the worst earthquake in the US?
The largest earthquake to hit the U.S. was on March 28, 1964, when a 9.2 magnitude quake struck Prince William Sound in Alaska.
Which type of fault is most likely to generate tsunamis?
Earthquakes generally occur on three types of faults: normal, strike-slip, and reverse (or thrust). Tsunamis can be generated by earthquakes on all of these faults, but most tsunamis, and the largest, result from earthquakes on reverse faults.
What are 5 interesting facts about 1964 Alaska earthquake?
Geologic shake-up. An aerial view of the Turnagain Heights landslide in Anchorage. ... Deadly tidal waves. Tsunami damage in Kodiak, Alaska (Image credit: USGS) ... Schoolhouse lives. ... Deadly ground. ... Snapped trees. ... The day the earth moved. ... Sloshing and jostling. ... Second-biggest earthquake.More items...•
Where was the largest earthquake in the world?
Valdivia, ChileThe earthquake that struck near Valdivia, Chile, in 1960 was the most powerful temblor in recorded history. The quake left about 2 million people homeless. On May 22, 1960, the most powerful earthquake in recorded history—magnitude 9.5—struck southern Chile.
Has a tsunami ever hit Alaska?
ANCHORAGE, Alaska (KTUU) - Alaska is home to the largest tsunami ever recorded. The 1,720-foot wave hit the tall banks of Lituya Bay in Southeast Alaska in 1958. There were two people who were in the bay who died, and four survived.
When was the worst earthquake in Alaska?
March 27, 1964On March 27, 1964 at 5:36pm local time, a M9. 2 earthquake rocked the Prince William Sound region of Alaska. This earthquake and ensuing tsunami took 131 lives (tsunami 122, earthquake 9), and caused about $2.3 billion in property loss (in 2013 dollars; equivalent to $311 million in 1964).
How big was the earthquake just now Alaska?
today: 3.6 in Sutton-Alpine, Alaska, United States.
When did the Alaska earthquake happen?
March 27, 19641964 Alaska earthquake / Start date
Where did the 1964 Alaska earthquake happen?
Alaska earthquake of 1964, earthquake that occurred in south-central Alaska on March 27, 1964, with a moment magnitude of 9.2. It released at least twice as much energy as the San Francisco earthquake of 1906 and was felt on land over an area of almost 502,000 square miles (1,300,000 square km).
The 1964 Great Alaska Earthquake and Tsunami - USGS
Free USGS Public Lecture February 27 . MENLO PARK, Calif. — On March 27 th, 1964, the second largest instrumentally recorded earthquake worldwide rocked southern Alaska for 4 to 5 minutes.In addition to the earthquake, the event triggered a major tsunami that caused casualties and damage from the Kodiak Islands to northern California.
Which fault zone has the ability to generate more energy?
Subduction zones have the ability to generate much more energy (magnitude) through their earthquakes, than the type of fault zones we have in Utah. Most of Utah’s faults are normal faults, which, in our case, occur in the middle of a tectonic plate. Much of Nevada and Utah is part of the Great Basin, which sits right on top ...
What was the largest earthquake in the world?
The largest quake on record was the M9.5 event in Chile in 1960. The U.S. Geological Survey also reports that parts of the coast sank, or subsided, as much as 8 feet, and other parts rose by as much as 38 feet.
What plate is sliding under the North American plate?
This Steven Eberlein TEDx talk describes how the Juan de Fuca Plate, a relatively small tectonic plate, is sliding under the North American Plate in the Pacific Northwest. Though the Alaska quake happened at a different plate boundary, this animation is excellent and demonstrates subduction zones.
What was the magnitude of the earthquake in 2014?
U.S.G.S. Fact sheet, 2014. The magnitude 9.2 quake was the largest earthquake recorded in the United States and the second-largest earthquake ever recorded by modern instruments.
What is the Great Basin?
Much of Nevada and Utah is part of the Great Basin, which sits right on top of the North American Plate. The North American Plate is not sliding under another plate; it is expanding due to heat from the earth’s mantle. Anciently, what we now know as San Francisco and Salt Lake City were about 300 miles apart.
Can a subduction zone cause an earthquake in Utah?
Faults in Utah are just not long enough to produce a magnitude 9 earthquake. Also, normal faults typically don’t generate the energy release that a subduction zone fault can. Subduction zones can be found off the coast of Alaska, Washington State, and the west coast of South America (Chile area), where earthquakes of magnitude 8 or greater are ...
Why do earthquakes happen in Alaska?
From the dramatic Southeast coast to the heights of the Alaska Range and the volcanic islands of the Aleutians, earthquakes build the landscapes that drive Alaska’s rivers, glaciers, and even climate zones. Most of these earthquakes—and all major earthquakes—can be traced to the movement of tectonic plates.
What is the cause of earthquakes in Alaska?
Unlike the subduction zone, these faults slip primarily in a side-to-side motion, with a different tectonic plate on each side. The earthquakes caused by this movement are shallow and occur primarily in the crust of the earth. This is a well-developed fault system that has been active for tens of millions of years and in historic times has hosted numerous earthquakes approaching magnitude 8. The 2013 magnitude 7.5 Queen Charlotte Fault Earthquake is a recent example.
How many earthquakes have magnitudes of 6 or greater?
Twenty-six of those had magnitudes of 6 or greater, and three had magnitudes of at least 7. Seventy-five percent of all earthquakes in the United States with magnitudes larger than five happen in Alaska. All Alaskans live with earthquake hazards.
How many earthquakes were there in Alaska in 2014?
George Island shook the normally quiet Pribilofs. And in 2018, a swarm in the eastern Brooks Range accounted for more than 2,000 of the year's record 55,000 earthquakes in Alaska.
Why is the Alaska Earthquake Center important?
All Alaskans live with earthquake hazards. The Alaska Earthquake Center exists to minimize our risks by understanding where earthquakes occur and why. Tracking the earthquakes that occur each day provides clues about the earthquakes that are likely in the future.
What earthquakes were caused by compressional force?
The resulting seismicity is remarkable for its variety and geographic reach: events like the 2002 magnitude 7.9 Denali Fault Earthquake, and the 1958 magnitude 7.3 Huslia earthquake, as well as the highly active Minto Flats Seismic Zone, all result from this powerful compressional force.
How often does the Earthquake Center detect earthquakes?
The Earthquake Center detects an earthquake every fifteen minutes, on average. In 2018, we reported an all-time high of over 54,000 earthquakes in Alaska. As our monitoring network improves, we report more earthquakes because we are able to detect smaller earthquakes across more of the state. As the EarthScope Transportable Array project added new seismic stations in previously unmonitored areas, we noticed an upward trend of detectable earthquakes from around the state.
Why are earthquakes common in Alaska?
Nestled off Alaska's southern shoreline, the Aleutian Trench is a deep oceanic groove that is the result of colliding tectonic plates— the ever-shifting slabs of rock that make up Earth's surface. The Aleutian Trench forms where the northern edge of the Pacific plate plunges deep underneath the North American plate.
How deep was the fault that let loose?
While details are still emerging about the specific fault that let loose in this case, researchers believe that the rupture was centered relatively deep in the Earth, roughly 25 miles below the surface. That's good news for locals, says Caruso.
What are the risks in the aftermath?
The USGS estimates there's a 35 percent chance of between a hundred million and a billion dollars of economic damage in the region.
What does magnitude tell you about an earthquake?
Magnitude is a measure of an earthquake's energy release, and it can only tell you so much about what any given event feels like at the surface. Differences in regional geology and even the depth of the quake can affect how much the locals feel Earth's trembles.
When did the Wasilla earthquake happen?
This aerial photo shows damage on Vine Road south of Wasilla, Alaska, after an earthquake struck the region on November 30, 2018.
Was the November 30 earthquake a volcanic event?
Importantly, the November 30 earthquake was not related to any volcanic activity, according to the Alaska Volcano Observatory. It also wasn't directly related to the subduction zone, explains Paul Caruso, a geophysicist with the U.S. Geological Survey.
Was the Alaska earthquake a big one?
The quake was “certainly a pretty big one,” says Ben Andrews, the director of the Smithsonian's Global Volcanism Program. So far, reports suggest that the earthquake and its aftershocks were tough on the region's infrastructure, but very few fatalities are expected, in part because Alaska is prepared for such an event.
What is the pattern of seismicity in Alaska?
The general pattern of seismicity follows the Pacific plate as it subducts beneath Alaska. Because the production of earthquakes at our tectonic plate boundary is an ongoing process, it is imperative that Alaskans be prepared to protect their families and help their neighbors in the event of an emergency.
What is the southern edge of Alaska?
The southern edge of our state is an active tectonic plate boundary where the Pacific plate subducts (i.e., dives beneath) the North American plate along the great Alaska-Aleutian Megathrust. 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. In Alaska, the Pacific plate, relative to the North American plate, moves at a rate of ~5.5+ cm/yr (~2.2+ in/yr). The Fairweather fault system in southeast Alaska (over 620 miles long) is the primary strike-slip structure that accommodates ongoing subduction. Plate convergence at the southern margin of the state drives distributed deformation on secondary faults over 400 miles northward into the continental interior. These secondary faults have also generated several significant historic earthquakes (such as the 200+ mile-long 2002 M 7.9 Denali fault rupture), and we are still discovering faults that are capable of large earthquake displacements.
When was the second largest earthquake in the world?
On Good Friday, March 28, 1964 , south-central Alaska was struck by the second-largest earthquake ever recorded. The M 9.2 earthquake ruptured a patch of the subduction zone that was ~500 miles long and 100–175 miles wide, producing vertical displacements over an area of about 110,039 square miles in south-central Alaska (Plafker, 1969). Widespread areas south of the Alaska coastline were raised up as much as 18 ft whereas other areas dropped as much as 6 ft. Portions of the overriding crust moved seaward as much as 50 feet in a matter of minutes.
Which state has the most earthquakes?
Earthquakes. Alaska is the most seismically active state in the country, has had multiple "great" (Magnitude [M] 8 or larger) historic earthquakes, and has the potential to generate the largest earthquakes in the world. On average, Alaska has had one M 8+ earthquake every 13 years, one M 7–8 earthquake every two years, ...
Why are the plates moving but locked at the subduction zone?
Because the plates are continuously moving, but are locked at the subduction zone, the stress imparted to the locked zone results in a build-up of energy and deformation in the surrounding plates—regions of uplift and subsidence (i.e., down-dropping) at the plate boundary (part B).
What year did Alaska have the second largest earthquake?
The state also experienced the second-largest earthquake to ever hit the US - - a 9.2-magnitude in 1964. Friday’s 7.0 magnitude earthquake near Anchorage is no surprise to experts. The state is located along the Pacific “Ring of Fire” and joins the Pacific and North American plates.
How many earthquakes did Alaska have?
From Friday’s quake to early Saturday morning, parts of Alaska experienced about 194 earthquakes, according to USGS. “These numbers can change by the minute, people can be expected to feel aftershocks for some time,” Baldwin told CNN. And yet, Alaska is frequently overshadowed by another earthquake-prone state.
Where is the fastest moving tectonic fault?
One of the fastest-moving underwater tectonic faults in the world is in southeastern Alaska, according to the USGS. “With a slip rate of more than 2 inches per year, this fault may be one of the fastest-moving strike-slip faults in the world,” Baldwin said. In comparison, the San Andreas fault in California slips about an inch to an inch-and-a-half ...
Which state has the most earthquakes?
Alaska has the most earthquakes in the US. Here's why | CNN
Why is Alaska so prone to earthquakes?
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 plates—the Pacific Plate and the North American Plate.
How long did the Great Alaska earthquake last?
Aftershocks from the quake continued for three weeks The powerful tremors lasted for nearly five minutes and were felt over a large area of Alaska and in parts of the western Yukon Territory and British Columbia. Aftershocks from the quake continued for three weeks. The epicenter of the Great Alaska Earthquake was about 12 miles north ...
What were the major damage caused by the Anchorage earthquake?
Massive landslides were triggered by the quake near downtown Anchorage and several residential areas, damaging or destroying about 30 blocks of dwellings and commercial buildings. Water mains and gas, sewer, telephone and electrical systems were all damaged or destroyed due to the landslides.
How much damage did the Alaska tsunami cause?
A Costly Disaster. The earthquake and ensuing tsunamis caused about $2.3 billion of damage The earthquake and ensuing tsunamis caused about $2.3 billion of damage (equivalent to $311 million in 1964). President Lyndon Johnson declared the entire state of Alaska a major disaster area a day after the earthquake.
What is NCEI tsunami?
NCEI is the global data and information service for tsunamis. Global historical tsunami data, including more information about the Great Alaska Earthquake, are available via interactive maps and a variety of web services.
How high did the tsunami in Alaska go?
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. Scientists measured a wave runup of 220 feet in the Valdez Inlet.
What towns were hit by the Great Alaska earthquake?
Towns such as Whittier, Alaska, were inundated by tsunami waves before the earthquake had even subsided. The Government Hill Elementary School in Anchorage was torn apart in a landslide created by the Great Alaska Earthquake.
How A Subduction Zone Works
- This Steven Eberlein TEDx talk describes how the Juan de Fuca Plate, a relatively small tectonic plate, is sliding under the North American Plate in the Pacific Northwest. Though the Alaska quake happened at a different plate boundary, this animation is excellent and demonstrates subduction zones.
So How Does This Compare to Utah’s Faults?
- Subduction zones have the ability to generate much more energy (magnitude) through their earthquakes, than the type of fault zones we have in Utah. Most of Utah’s faults are normal faults, which, in our case, occur in the middle of a tectonic plate. Much of Nevada and Utah is part of the Great Basin, which sits right on top of the North American Plate. The North American Plate is no…
Why Can’T We Have A Magnitude 9 Earthquake Here?
- Faults in Utah are just not long enough to produce a magnitude 9 earthquake. Also, normal faults typically don’t generate the energy release that a subduction zone fault can. Subduction zones can be found off the coast of Alaska, Washington State, and the west coast of South America (Chile area), where earthquakes of magnitude 8 or greater are possible. According to research, Utah’s …