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World-Wide Standard Seismograph Network
__NOTOC__ The World-Wide Standardized Seismograph Network (WWSSN) – originally the World-Wide Network of Seismograph Stations (WWNSS) – was a global network of about 120 seismograph stations built in the 1960s that generated an unprecedented collection of high quality seismic data. This data enabled seismology to become a quantitative science, elucidated the focal mechanisms of earthquakes and the structure of the earth's crust, and contributed to the development of plate tectonic theory. The WWSSN is credited with spurring a renaissance in seismological research. The WWSSN also "created a global network infrastructure, including the data-exchange procedures and station technical capabilities needed to support the establishment of the more advanced networks in operation today", and has been the model for every global seismic network since then. A principal feature of the WWSSN was that each station had identical equipment, uniformly calibrated. These consisted of three short-pe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seismograph
A seismometer is an instrument that responds to ground noises and shaking such as caused by earthquakes, volcanic eruptions, and explosions. They are usually combined with a timing device and a recording device to form a seismograph. The output of such a device—formerly recorded on paper (see picture) or film, now recorded and processed digitally—is a seismogram. Such data is used to locate and characterize earthquakes, and to study the Earth's internal structure. Basic principles A simple seismometer, sensitive to up-down motions of the Earth, is like a weight hanging from a spring, both suspended from a frame that moves along with any motion detected. The relative motion between the weight (called the mass) and the frame provides a measurement of the vertical ground motion. A rotating drum is attached to the frame and a pen is attached to the weight, thus recording any ground motion in a seismogram. Any movement from the ground moves the frame. The mass tends not to m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seismology
Seismology (; from Ancient Greek σεισμός (''seismós'') meaning "earthquake" and -λογία (''-logía'') meaning "study of") is the scientific study of earthquakes and the propagation of elastic waves through the Earth or through other planet-like bodies. It also includes studies of earthquake environmental effects such as tsunamis as well as diverse seismic sources such as volcanic, tectonic, glacial, fluvial, oceanic, atmospheric, and artificial processes such as explosions. A related field that uses geology to infer information regarding past earthquakes is paleoseismology. A recording of Earth motion as a function of time is called a seismogram. A seismologist is a scientist who does research in seismology. History Scholarly interest in earthquakes can be traced back to antiquity. Early speculations on the natural causes of earthquakes were included in the writings of Thales of Miletus (c. 585 BCE), Anaximenes of Miletus (c. 550 BCE), Aristotle (c. 340 BCE), and Zha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plate Tectonics
Plate tectonics (from the la, label=Late Latin, tectonicus, from the grc, τεκτονικός, lit=pertaining to building) is the generally accepted scientific theory that considers the Earth's lithosphere to comprise a number of large tectonic plates which have been slowly moving since about 3.4 billion years ago. The model builds on the concept of ''continental drift'', an idea developed during the first decades of the 20th century. Plate tectonics came to be generally accepted by geoscientists after seafloor spreading was validated in the mid to late 1960s. Earth's lithosphere, which is the rigid outermost shell of the planet (the crust and upper mantle), is broken into seven or eight major plates (depending on how they are defined) and many minor plates or "platelets". Where the plates meet, their relative motion determines the type of plate boundary: '' convergent'', '' divergent'', or ''transform''. Earthquakes, volcanic activity, mountain-building, and oceanic tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seismogram
A seismogram is a graph output by a seismograph. It is a record of the ground motion at a measuring station as a function of time. Seismograms typically record motions in three cartesian axes (x, y, and z), with the z axis perpendicular to the Earth's surface and the x- and y- axes parallel to the surface. The energy measured in a seismogram may result from an earthquake or from some other source, such as an explosion. Seismograms can record many things, and record many little waves, called microseisms. These tiny microseisms can be caused by heavy traffic near the seismograph, waves hitting a beach, the wind, and any number of other ordinary things that cause some shaking of the seismograph. Historically, seismograms were recorded on paper attached to rotating drums, a kind of chart recorder. Some used pens on ordinary paper, while others used light beams to expose photosensitive paper. Today, practically all seismograms are recorded digitally to make analysis by computer eas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lloyd Berkner
Lloyd Viel Berkner (February 1, 1905 in Milwaukee, Wisconsin – June 4, 1967 in Washington, D.C.) was an American physicist and engineer. He was one of the inventors of the measuring device that since has become standard at ionospheric stations because it measures the height and electron density of the ionosphere. The data obtained in the worldwide net of such instruments were important for the developing theory of short wave radio propagation to which Berkner himself gave important contributions. Berkner was elected to the United States National Academy of Sciences in 1948. Later he investigated the development of the Earth's atmosphere. Since he needed data from the whole world, he proposed the International Geophysical Year in 1950. At that time, the IGY was the largest cooperative study of the Earth ever undertaken. Berkner was elected a Fellow of the American Academy of Arts and Sciences and a member of the American Philosophical Society in 1956. The IGY was carried out ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Defense Advanced Research Projects Agency
The Defense Advanced Research Projects Agency (DARPA) is a research and development agency of the United States Department of Defense responsible for the development of emerging technologies for use by the military. Originally known as the Advanced Research Projects Agency (ARPA), the agency was created on February 7, 1958, by President Dwight D. Eisenhower in response to the Soviet Union, Soviet launching of Sputnik 1 in 1957. By collaborating with academia, industry, and government partners, DARPA formulates and executes research and development projects to expand the frontiers of technology and science, often beyond immediate U.S. military requirements.Dwight D. Eisenhower and Science & Technology, (2008). Dwight D. Eisenhower Memorial CommissionSource ''The Economist'' has called DARPA the agency "that shaped the modern world," and pointed out that "Moderna COVID-19 vaccine, Moderna's COVID-19 vaccine sits alongside weather satellites, Global Positioning System, GPS, Unmann ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Incorporated Research Institutions For Seismology
IRIS (Incorporated Research Institutions for Seismology) is a university research consortium dedicated to exploring the Earth's interior through the collection and distribution of seismographic data. IRIS programs contribute to scholarly research, education, earthquake hazard mitigation, and the verification of a Comprehensive Nuclear-Test-Ban Treaty. Support for IRIS comes from the National Science Foundation, other federal agencies, universities, and private foundations. IRIS supports five major components, the Data Management Center (DMC), the Portable Array Seismic Studies of the Continental Lithosphere (PASSCAL), the Global Seismographic Network (GSN), the Transportable Array (USARRAY), and the Education and Public Outreach Program (EPO). IRIS maintains a Corporate Office in Washington, DC. IRIS's Education and Public Outreach Program provides resources for educators and the general public to advance awareness and understanding of seismology and earth science while inspiring c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Limited Test Ban Treaty
The Partial Test Ban Treaty (PTBT) is the abbreviated name of the 1963 Treaty Banning Nuclear Weapon Tests in the Atmosphere, in Outer Space and Under Water, which prohibited all test detonations of nuclear weapons except for those conducted underground. It is also abbreviated as the Limited Test Ban Treaty (LTBT) and Nuclear Test Ban Treaty (NTBT), though the latter may also refer to the Comprehensive Nuclear-Test-Ban Treaty (CTBT), which succeeded the PTBT for ratifying parties. Negotiations initially focused on a comprehensive ban, but that was abandoned because of technical questions surrounding the detection of underground tests and Soviet concerns over the intrusiveness of proposed verification methods. The impetus for the test ban was provided by rising public anxiety over the magnitude of nuclear tests, particularly tests of new thermonuclear weapons (hydrogen bombs), and the resulting nuclear fallout. A test ban was also seen as a means of slowing nuclear proliferation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Project Vela
Project Vela was a project undertaken by the United States Department of DefenseU.S. Department of Defense. Advanced Research Projects Agency. (1961, July 20). ADDENDUM to: Proceedings of Symposium: Project Vela (1st ed.) (263145). Washington, DC: U.S. Government Printing Office. Retrieved May 24, 2017 from the World Wide Web: . to develop and implement methods to monitor compliance with the 1963 Partial Test Ban Treaty. This treaty banned the testing of nuclear weapons in the atmosphere, in outer space, and underwater, effectively meaning nuclear tests were only to be permitted underground. Early history In August 1959, several groups focused on detecting underground nuclear tests were established within the US Department of Defense; on September 2, 1959, the Secretary of Defense assigned the research responsibilities to the Advanced Research Projects Agency (ARPA). This initial assignment involved seven tasks: creating a worldwide network of standardized seismological stations; co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seismology
Seismology (; from Ancient Greek σεισμός (''seismós'') meaning "earthquake" and -λογία (''-logía'') meaning "study of") is the scientific study of earthquakes and the propagation of elastic waves through the Earth or through other planet-like bodies. It also includes studies of earthquake environmental effects such as tsunamis as well as diverse seismic sources such as volcanic, tectonic, glacial, fluvial, oceanic, atmospheric, and artificial processes such as explosions. A related field that uses geology to infer information regarding past earthquakes is paleoseismology. A recording of Earth motion as a function of time is called a seismogram. A seismologist is a scientist who does research in seismology. History Scholarly interest in earthquakes can be traced back to antiquity. Early speculations on the natural causes of earthquakes were included in the writings of Thales of Miletus (c. 585 BCE), Anaximenes of Miletus (c. 550 BCE), Aristotle (c. 340 BCE), and Zha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
