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2013 Craig, Alaska Earthquake
The 2013 Craig, Alaska earthquake (also known as the Queen Charlotte Fault earthquake) struck on January 5, at 12:58 am ( UTC–7) near the city of Craig and Hydaburg, on Prince of Wales Island. The 7.5 earthquake came nearly three months after an 7.8 quake struck Haida Gwaii on October 28, in 2012. The quake prompted a regional tsunami warning to British Columbia and Alaska, but it was later cancelled. Due to the remote location of the quake, there were no reports of casualties or damages. Tectonic setting The Queen Charlotte Fault is a major right-lateral (dextral) strike-slip and transform fault running off the coast of British Columbia and into Southern Alaska, through the Saint Elias Range for more than 700 miles. Its southernmost section joins a spreading ridge of the Gorda Plate and the Cascadia subduction zone while the northern termination section joins the a thrust fault where the Yakutat terrane plows into the North American Plate. It has been the source of seve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Queen Charlotte Fault
The Queen Charlotte Fault is an active transform fault that marks the boundary of the North American plate and the Pacific plate. It is Canada's right-lateral strike-slip equivalent to the San Andreas Fault to the south in California. The Queen Charlotte Fault forms a triple junction south with the Cascadia subduction zone and the Explorer Ridge (the Queen Charlotte Triple Junction). The Queen Charlotte Fault (QCF) forms a transpressional plate boundary, and is as active as other major transform fault systems (i.e. San Andreas, Alpine) in terms of slip rates and seismogenic potential. It sustains the highest known deformation rates among continental or continent-ocean transform systems globally, accommodating greater than 50mm/yr dextral offset. The entire approximately 900 km offshore length has ruptured in seven greater than magnitude 7 events during the last century, making the cumulative historical seismic moment release higher than any other modern transform plate bound ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1949 Queen Charlotte Islands Earthquake
The 1949 Queen Charlotte Islands earthquake struck Haida Gwaii (at the time known as the Queen Charlotte Islands) and the Pacific Northwest coast at 8:01 p.m. PDT on August 21. The earthquake had a moment magnitude of 8.0 and a surface wave magnitude of 8.1. The maximum Mercalli Intensity in the event was VIII (''Severe''). The interplate earthquake began in the ocean bottom just off the rugged coast of Graham Island. It ruptured along the Queen Charlotte Fault both northward and southward more than . Shaking was felt throughout British Columbia, parts of Washington, Oregon, Alberta, the Yukon, and Alaska. No deaths were reported in this earthquake. Earthquake The 1949 Queen Charlotte Islands earthquake was caused by a rupture on the Queen Charlotte Fault, which forms part of the boundary between the Pacific and North American plates. This fault runs from northern Vancouver Island, west of Haida Gwaii, up to the Gulf of Alaska. The earthquake ruptured the fault for a distan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Washington (state)
Washington (), officially the State of Washington, is a state in the Pacific Northwest region of the Western United States. Named for George Washington—the first U.S. president—the state was formed from the western part of the Washington Territory, which was ceded by the British Empire in 1846, by the Oregon Treaty in the settlement of the Oregon boundary dispute. The state is bordered on the west by the Pacific Ocean, Oregon to the south, Idaho to the east, and the Canadian province of British Columbia to the north. It was admitted to the Union as the 42nd state in 1889. Olympia is the state capital; the state's largest city is Seattle. Washington is often referred to as Washington state to distinguish it from the nation's capital, Washington, D.C. Washington is the 18th-largest state, with an area of , and the 13th-most populous state, with more than 7.7 million people. The majority of Washington's residents live in the Seattle metropolitan area, the center of trans ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seattle
Seattle ( ) is a seaport city on the West Coast of the United States. It is the seat of King County, Washington. With a 2020 population of 737,015, it is the largest city in both the state of Washington and the Pacific Northwest region of North America. The Seattle metropolitan area's population is 4.02 million, making it the 15th-largest in the United States. Its growth rate of 21.1% between 2010 and 2020 makes it one of the nation's fastest-growing large cities. Seattle is situated on an isthmus between Puget Sound (an inlet of the Pacific Ocean) and Lake Washington. It is the northernmost major city in the United States, located about south of the Canadian border. A major gateway for trade with East Asia, Seattle is the fourth-largest port in North America in terms of container handling . The Seattle area was inhabited by Native Americans for at least 4,000 years before the first permanent European settlers. Arthur A. Denny and his group of travelers, subsequ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hyder, Alaska
Hyder is a census-designated place in Prince of Wales-Hyder Census Area, Alaska, United States. The population was 87 at the 2010 census, down from 97 in 2000. Hyder is accessible by road only from Stewart, British Columbia, is popular with motorists wishing to visit Alaska without driving the length of the Alaska Highway, and is otherwise landlocked. It is the southernmost community in the state that can be reached via car (others can be reached only by boat or plane). Hyder is Alaska's easternmost town. Geography Hyder is located at (55.941442, -130.054504), at the end of the land border between Alaska and British Columbia and at the head of the Portland Canal, a long fjord which forms a portion of the border at the southeastern edge of the Alaska Panhandle. It sits about from Stewart, British Columbia by road, and from Ketchikan by air. According to the U.S. Census Bureau, the CDP has a total area of , all land. Climate Hyder has a fairly typical Southeastern Alask ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Klawock, Alaska
Klawock ( tli, Lawáak) is a city in Prince of Wales–Hyder Census Area, in the U.S. state of Alaska, on the west coast of Prince of Wales Island, on Klawock Inlet, across from Klawock Island. The population was 755 at the 2010 census, down from 854 in 2000. It is located from Ketchikan, from Craig, and from Hollis. History Klawock's first settlers were Tlingit who came from the northern winter village of Tuxekan. They used it as a fishing camp for the summer period, and called it by several different names: Klawerak, Tlevak, Clevak, and Klawak. The name "Klawock" is derived from the Tlingit name , the man who founded the community. In 1853 a Russian navigator referred to the village as "Klyakkhan", and in 1855 as "Thlewakh". In 1868, European Americans opened a trading post and a salmon saltery; some years later, in 1878, a San Francisco firm opened the first cannery in Alaska. In the following decades, several others were established. A United States post office was es ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aftershock
In seismology, an aftershock is a smaller earthquake that follows a larger earthquake, in the same area of the main shock, caused as the displaced crust adjusts to the effects of the main shock. Large earthquakes can have hundreds to thousands of instrumentally detectable aftershocks, which steadily decrease in magnitude and frequency according to a consistent pattern. In some earthquakes the main rupture happens in two or more steps, resulting in multiple main shocks. These are known as doublet earthquakes, and in general can be distinguished from aftershocks in having similar magnitudes and nearly identical seismic waveforms. Distribution of aftershocks Most aftershocks are located over the full area of fault rupture and either occur along the fault plane itself or along other faults within the volume affected by the strain associated with the main shock. Typically, aftershocks are found up to a distance equal to the rupture length away from the fault plane. The pattern ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earthquake Rupture
In seismology, an earthquake rupture is the extent of slip that occurs during an earthquake in the Earth's crust. Earthquakes occur for many reasons that include: landslides, movement of magma in a volcano, the formation of a new fault, or, most commonly of all, a slip on an existing fault. Nucleation A tectonic earthquake begins by an initial rupture at a point on the fault surface, a process known as nucleation. The scale of the nucleation zone is uncertain, with some evidence, such as the rupture dimensions of the smallest earthquakes, suggesting that it is smaller than 100 m while other evidence, such as a slow component revealed by low-frequency spectra of some earthquakes, suggest that it is larger. The possibility that the nucleation involves some sort of preparation process is supported by the observation that about 40% of earthquakes are preceded by foreshocks. However, some large earthquakes, such as the M8.6 1950 India - China earthquake., have no foreshocks and it re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Supershear Earthquake
In seismology, a supershear earthquake is an earthquake in which the propagation of the rupture along the fault surface occurs at speeds in excess of the seismic shear wave (S-wave) velocity. This causes an effect analogous to a sonic boom. Rupture propagation velocity During seismic events along a fault surface the displacement initiates at the focus and then propagates outwards. Typically for large earthquakes the focus lies towards one end of the slip surface and much of the propagation is unidirectional (e.g. the 2008 Sichuan and 2004 Indian Ocean earthquakes). Theoretical studies have in the past suggested that the upper bound for propagation velocity is that of Rayleigh waves, approximately 0.92 of the shear wave velocity. However, evidence of propagation at velocities between S-wave and compressional wave (P-wave) values have been reported for several earthquakesArchuleta,R.J. 1984A faulting model for the 1979 Imperial Valley earthquake J. Geophys. Res., 89, 4559–4585. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coulomb Stress Transfer
Coulomb stress transfer is a seismic-related geological process of stress changes to surrounding material caused by local discrete deformation events. Using mapped displacements of the Earth's surface during earthquakes, the computed Coulomb stress changes suggest that the stress relieved during an earthquake not only dissipates but can also move up and down fault segments, concentrating and promoting subsequent tremors. Importantly, Coulomb stress changes have been applied to earthquake-forecasting models that have been used to assess potential hazards related to earthquake activity. Coulomb stress change The Coulomb failure criterion requires that the Coulomb stress exceeds a value σf defined by the shear stress τB, normal stress σB, pore pressure p, and coefficient of friction μ of a failure plane, such that It is also often assumed that changes in pore fluid pressure induced by changes in stress are proportional to the normal stress change across the fault plane. These ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seismic Gap
A seismic gap is a segment of an active fault known to produce significant earthquakes that has not slipped in an unusually long time, compared with other segments along the same structure. There is a hypothesis or theory that states that over long periods of time, the displacement on any segment must be equal to that experienced by all the other parts of the fault. Any large and longstanding gap is, therefore, considered to be the fault segment most likely to suffer future earthquakes. The applicability of this approach has been criticised by some seismologists although earthquakes sometimes have occurred in previously-identified seismic gaps. Examples Loma Prieta Seismic Gap, California Prior to the 1989 Loma Prieta earthquake( = 6.9), that segment of the San Andreas fault system recorded much less seismic activity than other parts of the fault. The main shock and aftershocks of the 1989 event occurred within the previous seismic gap. Central Kuril gap, Russia Immediately foll ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
San Andreas Fault
The San Andreas Fault is a continental transform fault that extends roughly through California. It forms the tectonics, tectonic boundary between the Pacific Plate and the North American Plate, and its motion is Fault (geology)#Strike-slip faults, right-lateral strike-slip (horizontal). The fault divides into three segments, each with different characteristics and a different degree of earthquake risk. The slip rate along the fault ranges from /yr. It was formed by a transform boundary. The fault was identified in 1895 by Professor Andrew Lawson of University of California, Berkeley, UC Berkeley, who discovered the northern zone. It is often described as having been named after San Andreas Lake, a small body of water that was formed in a valley between the two plates. However, according to some of his reports from 1895 and 1908, Lawson actually named it after the surrounding San Andreas Valley. Following the 1906 San Francisco earthquake, Lawson concluded that the fault extende ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
