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New Madrid Fault
The New Madrid Seismic Zone (), sometimes called the New Madrid Fault Line, is a major seismic zone and a prolific source of intraplate earthquakes (earthquakes within a tectonic plate) in the Southern and Midwestern United States, stretching to the southwest from New Madrid, Missouri. The New Madrid fault system was responsible for the 1811–12 New Madrid earthquakes, and has the potential to produce large earthquakes in the future. Since 1812, frequent smaller earthquakes have been recorded in the area. Earthquakes that occur in the New Madrid Seismic Zone potentially threaten parts of seven American states: Illinois, Indiana, Missouri, Arkansas, Kentucky, Tennessee, and Mississippi. Location The -long seismic zone, which extends into five states, stretches southward from Cairo, Illinois; through Hayti, Caruthersville, and New Madrid in Missouri; through Blytheville into Marked Tree in Arkansas. It also covers a part of West Tennessee, near Reelfoot Lake, extending sou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seismic Zone
In seismology, a seismic zone or seismic belt is an area of seismicity potentially sharing a common cause. It may also be a region on a map for which a common areal rate of seismicity is assumed for the purpose of calculating probabilistic ground motions. An obsolete definition is a region on a map in which a common level of seismic design is required. A type of seismic zone is a Wadati–Benioff zone which corresponds with the down-going slab in a subduction zone. Examples *Charlevoix Seismic Zone (Quebec, Canada) *New Madrid Seismic Zone (Midwestern United States) *South West Seismic Zone (Western Australia) See also *List of fault zones This list covers all Fault (geology), faults and fault-systems that are either geologically important or connected to prominent seismic activity. It is not intended to list every notable fault, but only major fault zones. See also * Lists of ... References {{seismology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caruthersville, Missouri
Caruthersville is a city in and the county seat of Pemiscot County, Missouri, United States, located along the Mississippi River in the Bootheel region of the state's far southeast. The population was 5,562, according to the 2020 census. History Caruthersville lies in Missouri's Bootheel on the Mississippi River. The word "Pemiscot" comes from the word meaning "liquid mud" in the Fox language. Mississippi waters have frequently flooded the flatlands, creating fertile alluvial land valued for farming. Settling the floodplain has resulted in periodic problems for residents, as there are regular floods despite (and because of) elaborate constructed systems of levees and flood controls. Native Americans inhabited the land of the Caruthersville area for thousands of years before European settlement. The Mississippian culture built huge earthwork mounds throughout the Mississippi Valley. One such earthwork remains in this county, rising 270 feet above sea level about four miles s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Continental Drift
Continental drift is the hypothesis that the Earth's continents have moved over geologic time relative to each other, thus appearing to have "drifted" across the ocean bed. The idea of continental drift has been subsumed into the science of plate tectonics, which studies the movement of the continents as they ride on plates of the Earth's lithosphere. The speculation that continents might have 'drifted' was first put forward by Abraham Ortelius in 1596. A pioneer of the modern view of mobilism was the Austrian geologist Otto Ampferer.Helmut W. Flügel: Die virtuelle Welt des Otto Ampferer und die Realität seiner Zeit'. In: Geo. Alp., Vol. 1, 2004. The concept was independently and more fully developed by Alfred Wegener in 1912, but the hypothesis was rejected by many for lack of any motive mechanism. The English geologist Arthur Holmes later proposed mantle convection for that mechanism. History Early history Abraham Ortelius , Theodor Christoph Lilienthal (1756), A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aulacogen
An aulacogen is a failed arm of a triple junction. Aulacogens are a part of plate tectonics where oceanic and continental crust is continuously being created, destroyed, and rearranged on the Earth’s surface. Specifically, aulacogens are a rift zone, where new crust is formed, that is no longer active. Origin of term The term ''aulacogen'' is derived from Greek ''aulax'' 'furrow' and was suggested by the Soviet geologist Nikolay Shatsky in 1946. Formation A triple junction is the point where three tectonic plates meet; the boundaries of these plates are characterized by divergence, causing a rift zone or spreading center; a transform fault; or convergence causing subduction or uplift of crust and forming mountains. The failed arm of a triple junction can be either a transform fault that has been flooded with magma, or more commonly, an inactive rift zone. Aulacogen formation starts with the termination of an active rift zone, which leaves behind a graben-like formation. Over ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Precambrian
The Precambrian (or Pre-Cambrian, sometimes abbreviated pꞒ, or Cryptozoic) is the earliest part of Earth's history, set before the current Phanerozoic Eon. The Precambrian is so named because it preceded the Cambrian, the first period of the Phanerozoic Eon, which is named after Cambria, the Latinised name for Wales, where rocks from this age were first studied. The Precambrian accounts for 88% of the Earth's geologic time. The Precambrian is an informal unit of geologic time, subdivided into three eons ( Hadean, Archean, Proterozoic) of the geologic time scale. It spans from the formation of Earth about 4.6 billion years ago ( Ga) to the beginning of the Cambrian Period, about million years ago ( Ma), when hard-shelled creatures first appeared in abundance. Overview Relatively little is known about the Precambrian, despite it making up roughly seven-eighths of the Earth's history, and what is known has largely been discovered from the 1960s onwards. The Precambrian fossil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cambrian
The Cambrian Period ( ; sometimes symbolized C with bar, Ꞓ) was the first geological period of the Paleozoic Era, and of the Phanerozoic Eon. The Cambrian lasted 53.4 million years from the end of the preceding Ediacaran Period 538.8 million years ago (mya) to the beginning of the Ordovician Period mya. Its subdivisions, and its base, are somewhat in flux. The period was established as "Cambrian series" by Adam Sedgwick, who named it after Cambria, the Latin name for 'Cymru' (Wales), where Britain's Cambrian rocks are best exposed. Sedgwick identified the layer as part of his task, along with Roderick Murchison, to subdivide the large "Transition Series", although the two geologists disagreed for a while on the appropriate categorization. The Cambrian is unique in its unusually high proportion of sedimentary deposits, sites of exceptional preservation where "soft" parts of organisms are preserved as well as their more resistant shells. As a result, our understanding of the Ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fault (geology)
In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic forces, with the largest forming the boundaries between the plates, such as the megathrust faults of subduction zones or transform faults. Energy release associated with rapid movement on active faults is the cause of most earthquakes. Faults may also displace slowly, by aseismic creep. A ''fault plane'' is the plane that represents the fracture surface of a fault. A ''fault trace'' or ''fault line'' is a place where the fault can be seen or mapped on the surface. A fault trace is also the line commonly plotted on geologic maps to represent a fault. A ''fault zone'' is a cluster of parallel faults. However, the term is also used for the zone of crushed rock along a single fault. Prolonged motion along closely spaced faults can blur the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seismicity
Seismicity is a measure encompassing earthquake occurrences, mechanisms, and magnitude at a given geographical location. As such, it summarizes a region's seismic activity. The term was coined by Beno Gutenberg and Charles Francis Richter in 1941. Seismicity is studied by geophysicists. Calculation of seismicity Seismicity is quantitatively computed. Generally, the region under study is divided in equally sized areas defined by latitude and longitude, and the Earth's interior is divided into various depth intervals on account of Earth's layering: Up to depth, , and > . The usual formula to calculate seismicity is: S = \frac where : _i: is the energy of a single seismic event (i.e., earthquake); : _0: interval of latitude; : _0: interval of longitude : _0: interval of the hypocenter; : _0: interval of the time of the seismic event. : The result is seismicity as energy per cubic unit. See also * Moment magnitude scale * Plate tectonics * Seismology * Wadati–Benioff zo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wabash Valley Seismic Zone
The Wabash Valley Seismic Zone (also known as the Wabash Valley Fault System or Zone) is a tectonic region located in the Midwest of the United States, centered on the valley of the Lower Wabash River, along the state line between southeastern Illinois and southwestern Indiana. Geology The Wabash Valley Seismic Zone consists largely of vertically oriented ("normal") faults deeply buried under layers of sediment. Although the tectonics of the region are still not fully understood and are the subject of ongoing research, these faults are thought by some to be associated with a branch of the New Madrid aulacogen, an old rift zone where the lithosphere actively began to pull apart at perhaps two separate times in the distant past. Present-day GPS measurements show that the region deforms at about 1–2 mm/yr with compression along the Wabash Valley Fault Zone, and extension in SW Indiana. The crust in the area has been weakened by the numerous faults, which remain active sites ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dyersburg, Tennessee
Dyersburg is a city and the county seat of Dyer County, Tennessee, United States. It is located in northwest Tennessee, northeast of Memphis on the Forked Deer River. The population was 16,164 at the 2020 census, down 5.72% from the 2010 census. History Early history The lands that make up Dyersburg once belonged to the Chickasaw people. The final treaty by which they relinquished all of West Tennessee was signed in 1818. 19th century The first European settlers began to arrive in the area around 1819. In 1823, the Tennessee General Assembly passed an act to establish two new counties immediately west of the Tennessee River, Dyer County being one of them. John McIver and Joel H. Dyer donated for the new county seat, named Dyersburg, at a central location within the county known as "McIver's Bluff". In 1825, Dyer surveyed the town site into 86 lots. The first courthouse was built on the square in 1827. The current Classical Revival-style courthouse, designed by Asa Biggs in 19 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reelfoot Lake
Reelfoot Lake is a shallow natural lake located in the northwest portion of the U.S. state of Tennessee, in Lake and Obion Counties. Much of it is swamp-like, with bayou-like ditches (some natural, some man-made) connecting more open bodies of water called basins, the largest of which is called Blue Basin. Reelfoot Lake is noted for its Taxodium, bald cypress trees and its nesting pairs of bald eagles. Public use of the lake and grounds has been preserved since it was acquired by the state of Tennessee in the early 20th century and the area was established as Reelfoot Lake State Park. Lake Isom, a similar, smaller lake to the immediate south, has been designated as a National Wildlife Refuge area. In 1966, Reelfoot Lake was designated as a national natural landmark by the National Park Service. History According to the United States Geological Survey, Reelfoot Lake was formed in northwestern Tennessee when the region subsided during the 1811–12 New Madrid earthquakes, which wer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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