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Blind Thrust Earthquake
A blind thrust earthquake occurs along a thrust fault that does not show signs on the Earth's surface, hence the designation "blind". Such faults, being invisible at the surface, have not been mapped by standard surface geological mapping. Sometimes they are discovered as a by-product of oil exploration seismology; in other cases their existence is not suspected. Although such earthquakes are not amongst the most energetic, they are sometimes the most destructive, as conditions combine to form an urban earthquake which greatly affects urban seismic risk. A blind thrust earthquake is quite close, in meaning, to a buried rupture earthquake, if a buried rupture earthquake is not specifically about the fault, but signs the earthquake leaves, on the Earth's surface. Blind thrust faults Blind thrust faults generally exist near tectonic plate margins, in the broad disturbance zone. They form when a section of the Earth's crust is under high compressive stresses, due to plate margin col ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thrust Fault
A thrust fault is a break in the Earth's crust, across which older rocks are pushed above younger rocks. Thrust geometry and nomenclature Reverse faults A thrust fault is a type of reverse fault that has a dip of 45 degrees or less. If the angle of the fault plane is lower (often less than 15 degrees from the horizontal) and the displacement of the overlying block is large (often in the kilometer range) the fault is called an ''overthrust'' or ''overthrust fault''. Erosion can remove part of the overlying block, creating a ''fenster'' (or ''window'') – when the underlying block is exposed only in a relatively small area. When erosion removes most of the overlying block, leaving island-like remnants resting on the lower block, the remnants are called ''klippen'' (singular ''klippe''). Blind thrust faults If the fault plane terminates before it reaches the Earth's surface, it is referred to as a ''blind thrust'' fault. Because of the lack of surface evidence, blind thr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NASA
The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding the National Advisory Committee for Aeronautics (NACA), to give the U.S. space development effort a distinctly civilian orientation, emphasizing peaceful applications in space science. NASA has since led most American space exploration, including Project Mercury, Project Gemini, the 1968-1972 Apollo Moon landing missions, the Skylab space station, and the Space Shuttle. NASA supports the International Space Station and oversees the development of the Orion spacecraft and the Space Launch System for the crewed lunar Artemis program, Commercial Crew spacecraft, and the planned Lunar Gateway space station. The agency is also responsible for the Launch Services Program, which provides oversight of launch operations and countdown management f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surface Rupture Earthquake
In seismology, surface rupture (or ground rupture, or ground displacement) is the visible offset of the ground surface when an earthquake rupture along a fault affects the Earth's surface. Surface rupture is opposed by buried rupture, where there is no displacement at ground level. This is a major risk to any structure that is built across a fault zone that may be active, in addition to any risk from ground shaking. Surface rupture entails vertical or horizontal movement, on either side of a ruptured fault. Surface rupture can affect large areas of land. __TOC__ Lack of surface rupture Not every earthquake results in surface rupture, particularly for smaller and deeper earthquakes. In some cases, however, the lack of surface effects is because the fault that moved does not reach the surface. For example, the 1994 Northridge earthquake had a moment magnitude of 6.7, caused major damage in the Los Angeles area, occurred at below the Earth's surface, but did not cause surface ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Buried Rupture Earthquake
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Main Frontal Thrust
The Main Frontal Thrust (MFT), also known as the Himalayan Frontal Thrust (HFT) is a geological fault in the Himalayas that defines the boundary between the Himalayan foothills and Indo-Gangetic Plain. The fault is well expressed on the surface thus could be seen via satellite imagery. It is the youngest and southernmost thrust structure in the Himalaya deformation front. It is a splay branch of the Main Himalayan Thrust (MHT) as the root décollement. It runs parallel to other major splays of the MHT; Main Boundary Thrust (MBT) and Main Central Thrust (MCT). The Sunda Megathrust, which extends from the Banda Islands to Myanmar is joined with the MFT. The fault strikes in a NW-SE direction and dips at an angle of 20° to 30° in the north. Main Boundary Thrust The Main Boundary Thrust (MBT) is another major thrust fault in the Himalaya orogenic wedge that was active in the Cenozoic The Cenozoic ( ; ) is Earth's current geological era, representing the last 66million ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Puente Hills Fault
The Puente Hills Fault (also known as the Puente Hills Thrust Fault System) is an active geological fault that is located in the Los Angeles Basin in California. The thrust fault was discovered in 1999 and runs about in three discrete sections from the Puente Hills region in the southeast to just south of Griffith Park in the northwest. The fault is known as a blind thrust fault, as the fault plane does not extend to the surface. Large earthquakes on the fault are relatively infrequent but computer modeling has indicated that a major event could have substantial impact in the Los Angeles area. The fault is now thought to be responsible for one moderate earthquake in 1987 (the 1987 Whittier Narrows earthquake) and another light event that took place in 2010, with the former causing considerable damage and deaths. Geology The Los Angeles Basin is situated along the coast of Southern California at the confluence of the Transverse Ranges and the Peninsular Ranges. The basin is unde ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elysian Park Fault
Elysian Park Fault is an active blind thrust fault located in Central Los Angeles, California. Approximately 20 km (12.4 miles) long, the fault is believed to able to produce a destructive earthquake of magnitude 6.2–6.7, about every 500–1,300 years, similar in size and frequency to the 1971 San Fernando earthquake or 1994 Northridge earthquake. See also * Elysian Park, Los Angeles Elysian Park is a neighborhood in Central Los Angeles, California. It is a predominantly low-income community, and has a population of more than 2,600 people. A city park, Elysian Park, and Dodger Stadium are within the neighborhood, as are an a ... References {{California Faults Seismic faults of California Strike-slip faults Chino Hills (California) Geology of Riverside County, California Geology of San Bernardino County, California Geography of Corona, California Buried rupture earthquakes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Global Positioning System
The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of the global navigation satellite systems (GNSS) that provides geolocation and time information to a GPS receiver anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites. It does not require the user to transmit any data, and operates independently of any telephonic or Internet reception, though these technologies can enhance the usefulness of the GPS positioning information. It provides critical positioning capabilities to military, civil, and commercial users around the world. Although the United States government created, controls and maintains the GPS system, it is freely accessible to anyone with a GPS receiver. The GPS project was started by the U.S. Department of Defense in 1973. The first prototype spacecraft was lau ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Los Angeles
Los Angeles ( ; es, Los Ángeles, link=no , ), often referred to by its initials L.A., is the largest city in the state of California and the second most populous city in the United States after New York City, as well as one of the world's most populous megacities. Los Angeles is the commercial, financial, and cultural center of Southern California. With a population of roughly 3.9 million residents within the city limits , Los Angeles is known for its Mediterranean climate, ethnic and cultural diversity, being the home of the Hollywood film industry, and its sprawling metropolitan area. The city of Los Angeles lies in a basin in Southern California adjacent to the Pacific Ocean in the west and extending through the Santa Monica Mountains and north into the San Fernando Valley, with the city bordering the San Gabriel Valley to it's east. It covers about , and is the county seat of Los Angeles County, which is the most populous county in the United States with an estim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Petroleum
Petroleum, also known as crude oil, or simply oil, is a naturally occurring yellowish-black liquid mixture of mainly hydrocarbons, and is found in geological formations. The name ''petroleum'' covers both naturally occurring unprocessed crude oil and petroleum products that consist of refined crude oil. A fossil fuel, petroleum is formed when large quantities of dead organisms, mostly zooplankton and algae, are buried underneath sedimentary rock and subjected to both prolonged heat and pressure. Petroleum is primarily recovered by oil drilling. Drilling is carried out after studies of structural geology, sedimentary basin analysis, and reservoir characterisation. Recent developments in technologies have also led to exploitation of other unconventional reserves such as oil sands and oil shale. Once extracted, oil is refined and separated, most easily by distillation, into innumerable products for direct use or use in manufacturing. Products include fuels such as gasol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reflection Seismology
Reflection seismology (or seismic reflection) is a method of exploration geophysics that uses the principles of seismology to estimate the properties of the Earth's subsurface from reflected seismic waves. The method requires a controlled seismic source of energy, such as dynamite or Tovex blast, a specialized air gun or a seismic vibrator. Reflection seismology is similar to sonar and echolocation. This article is about surface seismic surveys; for vertical seismic profiles, see VSP. History Reflections and refractions of seismic waves at geologic interfaces within the Earth were first observed on recordings of earthquake-generated seismic waves. The basic model of the Earth's deep interior is based on observations of earthquake-generated seismic waves transmitted through the Earth's interior (e.g., Mohorovičić, 1910). The use of human-generated seismic waves to map in detail the geology of the upper few kilometers of the Earth's crust followed shortly thereafter and h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Erosion
Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is distinct from weathering which involves no movement. Removal of rock or soil as clastic sediment is referred to as ''physical'' or ''mechanical'' erosion; this contrasts with ''chemical'' erosion, where soil or rock material is removed from an area by dissolution. Eroded sediment or solutes may be transported just a few millimetres, or for thousands of kilometres. Agents of erosion include rainfall; bedrock wear in rivers; coastal erosion by the sea and waves; glacial plucking, abrasion, and scour; areal flooding; wind abrasion; groundwater processes; and mass movement processes in steep landscapes like landslides and debris flows. The rates at which such processes act control how fast a surface is eroded. Typically, physical erosion procee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
