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Dauki Fault
The Dauki fault is a major fault along the southern boundary of the Shillong Plateau that may be a source of destructive seismic hazards for the adjoining areas, including northeastern Bangladesh. The fault, inferred to go through the southern margin of the Shillong Plateau, is an east–west-trending reverse fault inclined towards the north. Marking the southern margins of Shillong Plateau (which is much steeper than the northern slope at about a height of 1500 m), the prominent East-West Dauki Fault System (5–6 km wide) is the most remarkable feature of the Plateau. This fault zone forms a sharp escarpment along the southern edge of the plateau. The steep escarpment indicates vertical displacement along the Dauki Fault Zone where the Bangladesh plains subside actively. Though the Dauki Fault Zone is shown as a single fault line on the geological map of Bangladesh (1990) but the images show that it is the combination of a number of en-echelon faults trending in different d ... [...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] |
1548 Bengal Earthquake
__NOTOC__ Year 1548 ( MDXLVIII) was a leap year starting on Sunday (link will display the full calendar) of the Julian calendar. Events January–June * February 14 – Battle of Uedahara: Firearms are used for the first time on the battlefield in Japan, and Takeda Shingen is defeated by Murakami Yoshikiyo. * April 1 – Sigismund II Augustus succeeds his father, Sigismund I the Old, as King of Poland and Grand Duke of Lithuania. * May 11 – The great fire in Brielle begins. * June ** Ming Chinese naval forces commanded by Zhu Wan destroy the pirate haven of Shuangyu, frequented by Chinese, Japanese and Portuguese smugglers. ** John Dee starts to study at the Old University of Leuven. July–December * July 7 – A marriage treaty is signed between Scotland and France, whereby five-year-old Mary, Queen of Scots, is betrothed to the future King Francis II of France. * August 7 – Mary, Queen of Scots, leaves for France. * October 20 – ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Buried Rupture Earthquakes
In seismology, a buried rupture earthquake, or blind earthquake, is an earthquake which does not produce a visible offset in the ground along the fault (as opposed to a surface rupture earthquake, which does). When the fault in question is a thrust fault, the earthquake is known as a blind thrust earthquake. Ground motion Recorded ground motions of large surface-rupture earthquakes are weaker than the ground motions from buried rupture earthquakes. Depth The asperity for a buried rupture earthquakes is in area deeper than roughly . Examples are the Loma Prieta earthquake, Northridge earthquake, and the Noto Hanto earthquake. Tsunamis As compared to the seabed surface rupture case, uplifted water outside the fault plane in buried rupture earthquakes makes for large tsunami waves. See also * Aseismic creep In geology, aseismic creep or fault creep is measurable surface displacement along a fault in the absence of notable earthquakes. Aseismic creep may also occur as "aft ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Active Faults
An active fault is a fault that is likely to become the source of another earthquake sometime in the future. Geologists commonly consider faults to be active if there has been movement observed or evidence of seismic activity during the last 10,000 years. * Active faulting is considered to be a geologic hazard - one related to earthquakes as a cause. Effects of movement on an active fault include strong ground motion, surface faulting, tectonic deformation, landslides and rockfalls, liquefaction, tsunamis, and seiches. Quaternary faults are those active faults that have been recognized at the surface and which have evidence of movement during the Quaternary Period. Related geological disciplines for ''active-fault'' studies include geomorphology, seismology, reflection seismology, plate tectonics, geodetics and remote sensing, risk analysis, and others. Location Active faults tend to occur in the vicinity of tectonic plate boundaries, and active fault research has focused ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neogene
The Neogene ( ), informally Upper Tertiary or Late Tertiary, is a geologic period and system that spans 20.45 million years from the end of the Paleogene Period million years ago ( Mya) to the beginning of the present Quaternary Period Mya. The Neogene is sub-divided into two epochs, the earlier Miocene and the later Pliocene. Some geologists assert that the Neogene cannot be clearly delineated from the modern geological period, the Quaternary. The term "Neogene" was coined in 1853 by the Austrian palaeontologist Moritz Hörnes (1815–1868). During this period, mammals and birds continued to evolve into modern forms, while other groups of life remained relatively unchanged. The first humans (''Homo habilis'') appeared in Africa near the end of the period. Some continental movements took place, the most significant event being the connection of North and South America at the Isthmus of Panama, late in the Pliocene. This cut off the warm ocean currents from the Pacific to th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sylhet
Sylhet ( bn, সিলেট) is a metropolitan city in northeastern Bangladesh. It is the administrative seat of the Sylhet Division. Located on the north bank of the Surma River at the eastern tip of Bengal, Sylhet has a subtropical climate and lush highland terrain. The city has a population of more than half a million and is one of the largest cities in Bangladesh after Dhaka, Chittagong and Khulna. Sylhet is one of Bangladesh's most important spiritual and cultural centres. Furthermore, it is one of the most economically important cities after Dhaka and Chittagong. The city produces the highest amount of tea and natural gas. The hinterland of the Sylhet valley is the largest oil and gas-producing region in Bangladesh. It is also the largest hub of tea production in Bangladesh. It is notable for its high-quality cane and agarwood. The city is served by the Osmani International Airport, named after General Bangabir M A G Osmani, the Commander-in-Chief of the Mukti Bahini duri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sedimentary Rock
Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles to settle in place. The particles that form a sedimentary rock are called sediment, and may be composed of geological detritus (minerals) or biological detritus (organic matter). The geological detritus originated from weathering and erosion of existing rocks, or from the solidification of molten lava blobs erupted by volcanoes. The geological detritus is transported to the place of deposition by water, wind, ice or mass movement, which are called agents of denudation. Biological detritus was formed by bodies and parts (mainly shells) of dead aquatic organisms, as well as their fecal mass, suspended in water and slowly piling up on the floor of water bodies (marine snow). Sedimentation may also occur as dissolved minerals precipitate from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bengal Foredeep
The Bengal Foredeep is one of the world's largest exogeosynclines. It runs parallel to the hinge zone of the Sub-Himalayan Foredeep. It is about 450 kilometers wide in southern Bangladesh, narrowing towards the northeast. Folded belts of the Burmese Alpide mobile belt mark its eastern boundary. It can be divided into further sub-zones: (1) the Faridpur Trough; (2) the Barisal High; (3) the Hatiya Trough; (4) the Sylhet Trough; and (5) the Madhupur High.Eldridge M. Moores, Rhodes Whitmore Fairbridge; Eldridge M. Moores, Rhodes Whitmore Fairbridge; Encyclopedia of European and Asian Regional Geology; page 67; Champion & Hall References Geography of Bangladesh {{Bangladesh-geo-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Indian Platform
Indian or Indians may refer to: Peoples South Asia * Indian people, people of Indian nationality, or people who have an Indian ancestor ** Non-resident Indian, a citizen of India who has temporarily emigrated to another country * South Asian ethnic groups, referring to people of the Indian subcontinent, as well as the greater South Asia region prior to the 1947 partition of India * Anglo-Indians, people with mixed Indian and British ancestry, or people of British descent born or living in the Indian subcontinent * East Indians, a Christian community in India Europe * British Indians, British people of Indian origin The Americas * Indo-Canadians, Canadian people of Indian origin * Indian Americans, American people of Indian origin * Indigenous peoples of the Americas, the pre-Columbian inhabitants of the Americas and their descendants ** Plains Indians, the common name for the Native Americans who lived on the Great Plains of North America ** Native Americans in the Uni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Upper Mantle (Earth)
The upper mantle of Earth is a very thick layer of rock inside the planet, which begins just beneath the crust (at about under the oceans and about under the continents) and ends at the top of the lower mantle at . Temperatures range from approximately at the upper boundary with the crust to approximately at the boundary with the lower mantle. Upper mantle material that has come up onto the surface comprises about 55% olivine, 35% pyroxene, and 5 to 10% of calcium oxide and aluminum oxide minerals such as plagioclase, spinel, or garnet, depending upon depth. Seismic structure The density profile through Earth is determined by the velocity of seismic waves. Density increases progressively in each layer, largely due to compression of the rock at increased depths. Abrupt changes in density occur where the material composition changes. The upper mantle begins just beneath the crust and ends at the top of the lower mantle. The upper mantle causes the tectonic plates to move. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haflong Thrust
The Haflong Thrust is the most persistent of the thrusts in the 400 km long Belt of Schuppen (BoS) in the western part of Nagaland.Haflong Thrust Banglapedia The Belt of Schuppen forms the outermost fringe of the mobile belt of the – basin and forms the most prominent morphotectonic unit of the Naga Hills, [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fold (geology)
In structural geology, a fold is a stack of originally planar surfaces, such as sedimentary strata, that are bent or curved during permanent deformation. Folds in rocks vary in size from microscopic crinkles to mountain-sized folds. They occur as single isolated folds or in periodic sets (known as ''fold trains''). Synsedimentary folds are those formed during sedimentary deposition. Folds form under varied conditions of stress, pore pressure, and temperature gradient, as evidenced by their presence in soft sediments, the full spectrum of metamorphic rocks, and even as primary flow structures in some igneous rocks. A set of folds distributed on a regional scale constitutes a fold belt, a common feature of orogenic zones. Folds are commonly formed by shortening of existing layers, but may also be formed as a result of displacement on a non-planar fault (''fault bend fold''), at the tip of a propagating fault (''fault propagation fold''), by differential compaction or due to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
