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Tornillo Event
A tornillo event is a low-frequency seismic event associated with volcanoes. The term, which means "screw" in Spanish, was coined in the mid-1990s at the Observatorio Vulcanológico y Sismológico de Pasto (OVSP) in Pasto, Colombia to describe seismic events seen at the Galeras volcano. A tornillo has the following characteristics that distinguish it from other seismic events: * very limited distribution of frequencies ( monochromatic) * a long coda that decays slowly * small amplitude Like volcanic tremor, tornillos are thought to be caused by magma Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natural sa ... moving at depth. ReferencesTornillo-type seismic signals at Galeras volcano, Colombia, 1992−1993 External linksObservatorio Vulcanológico y Sismológico de Pasto - INGEOMINAS S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spanish Language
Spanish ( or , Castilian) is a Romance languages, Romance language of the Indo-European language family that evolved from colloquial Latin spoken on the Iberian peninsula. Today, it is a world language, global language with more than 500 million native speakers, mainly in the Americas and Spain. Spanish is the official language of List of countries where Spanish is an official language, 20 countries. It is the world's list of languages by number of native speakers, second-most spoken native language after Mandarin Chinese; the world's list of languages by total number of speakers, fourth-most spoken language overall after English language, English, Mandarin Chinese, and Hindustani language, Hindustani (Hindi-Urdu); and the world's most widely spoken Romance languages, Romance language. The largest population of native speakers is in Mexico. Spanish is part of the Iberian Romance languages, Ibero-Romance group of languages, which evolved from several dialects of Vulgar Latin in I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pasto (Colombia)
Pasto, officially San Juan de Pasto (; "Saint John of Pasto"), is the capital of the department of Nariño, in southern Colombia. Pasto was founded in 1537 and named after indigenous people of the area. In the 2018 census, the city had approximately 480.000 inhabitants. Pasto is located in the Atriz Valley on the Andes cordillera, at the foot of the Galeras volcano. History The etymology of the word ''Pasto'' can be traced to the indigenous people who inhabited the region at the arrival of the Spanish conquerors, the Pastos. However, the Atriz Valley itself was inhabited by the Quillacingas. In the 2018 Colombian census, 163,873 people self-identified as Pasto, and in the 2010 Ecuadorian census, 1,409 people self-identified as Pasto. Pasto was founded in 1537 by the Spanish conquistador Sebastián de Belalcázar. In 1539 Lorenzo de Aldana, also a Spanish conquistador, moved the city to its current location, and established it under the name "San Juan de Pasto". A major ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Colombia
Colombia (, ; ), officially the Republic of Colombia, is a country in South America with insular regions in North America—near Nicaragua's Caribbean coast—as well as in the Pacific Ocean. The Colombian mainland is bordered by the Caribbean Sea to the north, Venezuela to the east and northeast, Brazil to the southeast, Ecuador and Peru to the south and southwest, the Pacific Ocean to the west, and Panama to the northwest. Colombia is divided into 32 departments and the Capital District of Bogotá, the country's largest city. It covers an area of 1,141,748 square kilometers (440,831 sq mi), and has a population of 52 million. Colombia's cultural heritage—including language, religion, cuisine, and art—reflects its history as a Spanish colony, fusing cultural elements brought by immigration from Europe and the Middle East, with those brought by enslaved Africans, as well as with those of the various Amerindian civilizations that predate colonization. Spanish is th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galeras
Galeras (Urcunina among the 16th-century Indigenous peoples of the Americas, indigenous people) is an Andes, Andean stratovolcano in the Colombian Departments of Colombia, department of Nariño Department, Nariño, near the departmental capital Pasto (Colombia), Pasto. Its summit rises above sea level. It has erupted frequently since the Spanish conquest of the Muisca, Spanish conquest, with its first historical eruption being recorded on December 7, 1580. A 1993 eruption killed nine people, including six scientists who had descended into the volcano's crater to sample gases and take gravity measurements in an attempt to be able to predict future eruptions. It is currently the most active volcano in Colombia. Geological history Galeras has been an active volcano for at least a million years, with andesite as the dominant product. Two major caldera-forming eruptions have occurred, the first about 560,000 years ago in an eruption which expelled about of material. The second som ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcano
A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates are diverging or converging, and most are found underwater. For example, a mid-ocean ridge, such as the Mid-Atlantic Ridge, has volcanoes caused by divergent tectonic plates whereas the Pacific Ring of Fire has volcanoes caused by convergent tectonic plates. Volcanoes can also form where there is stretching and thinning of the crust's plates, such as in the East African Rift and the Wells Gray-Clearwater volcanic field and Rio Grande rift in North America. Volcanism away from plate boundaries has been postulated to arise from upwelling diapirs from the core–mantle boundary, deep in the Earth. This results in hotspot volcanism, of which the Hawaiian hotspot is an example. Volcanoes are usually not created where two tectonic plates slide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Response Spectrum
A response spectrum is a plot of the peak or steady-state response (displacement, velocity or acceleration) of a series of oscillators of varying natural frequency, that are forced into motion by the same base vibration or shock. The resulting plot can then be used to pick off the response of any linear system, given its natural frequency of oscillation. One such use is in assessing the peak response of buildings to earthquakes. The science of strong ground motion may use some values from the ground response spectrum (calculated from recordings of surface ground motion from seismographs) for correlation with seismic damage. If the input used in calculating a response spectrum is steady-state periodic, then the steady-state result is recorded. Damping must be present, or else the response will be infinite. For transient input (such as seismic ground motion), the peak response is reported. Some level of damping is generally assumed, but a value will be obtained even with no damping. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monochromatic
A monochrome or monochromatic image, object or color scheme, palette is composed of one color (or lightness, values of one color). Images using only Tint, shade and tone, shades of grey are called grayscale (typically digital) or Black and white, black-and-white (typically analog). In physics, Monochromatic radiation, monochromatic light refers to electromagnetic radiation that contains a narrow band of wavelengths, which is a distinct concept. Application Of an image, the term monochrome is usually taken to mean the same as black and white or, more likely, grayscale, but may also be used to refer to other combinations containing only tones of a single color, such as green-and-white or green-and-red. It may also refer to Sepia tone, sepia displaying tones from light tan to dark brown or cyanotype ("blueprint") images, and early photographic methods such as daguerreotypes, ambrotypes, and tintypes, each of which may be used to produce a monochromatic image. In computing, monoc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coda (music)
In music, a coda () (Italian for "tail", plural ''code'') is a passage that brings a piece (or a movement) to an end. It may be as simple as a few measures, or as complex as an entire section. In classical music The presence of a coda as a structural element in a movement is especially clear in works written in particular musical forms. Codas were commonly used in both sonata form and variation movements during the Classical era. In a sonata form movement, the recapitulation section will, in general, follow the exposition in its thematic content, while adhering to the home key. The recapitulation often ends with a passage that sounds like a termination, paralleling the music that ended the exposition; thus, any music coming after this termination will be perceived as extra material, i.e., as a coda. In works in variation form, the coda occurs following the last variation and will be very noticeable as the first music not based on the theme. One of the ways that Beethoven ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amplitude
The amplitude of a periodic variable is a measure of its change in a single period (such as time or spatial period). The amplitude of a non-periodic signal is its magnitude compared with a reference value. There are various definitions of amplitude (see below), which are all functions of the magnitude of the differences between the variable's extreme values. In older texts, the phase of a periodic function is sometimes called the amplitude. Definitions Peak amplitude & semi-amplitude For symmetric periodic waves, like sine waves, square waves or triangle waves ''peak amplitude'' and ''semi amplitude'' are the same. Peak amplitude In audio system measurements, telecommunications and others where the measurand is a signal that swings above and below a reference value but is not sinusoidal, peak amplitude is often used. If the reference is zero, this is the maximum absolute value of the signal; if the reference is a mean value (DC component), the peak amplitude is the maximu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanic Tremor
A harmonic tremor is a sustained release of seismic and infrasonic energy typically associated with the underground movement of magma, the venting of volcanic gases from magma, or both. It is a long-duration release of seismic energy, with distinct spectral lines, that often precedes or accompanies a volcanic eruption. More generally, a volcanic tremor is a sustained signal that may or may not possess these harmonic spectral features. Being a long-duration continuous signal from a temporally extended source, a volcanic tremor contrasts distinctly with transient sources of seismic radiation, such as tremors that are typically associated with earthquakes and explosions. The relation between long-period events and an imminent eruption was first observed by Bernard Chouet, a volcanologist who was working at the United States Geological Survey.U.S. TV program on use of long-period events to predict volcanic eruptions: "Nova: Volcano's Deadly Warning": https://www.pbs.org/wgbh/nova ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magma
Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natural satellites. Besides molten rock, magma may also contain suspended crystals and gas bubbles. Magma is produced by melting of the mantle or the crust in various tectonic settings, which on Earth include subduction zones, continental rift zones, mid-ocean ridges and hotspots. Mantle and crustal melts migrate upwards through the crust where they are thought to be stored in magma chambers or trans-crustal crystal-rich mush zones. During magma's storage in the crust, its composition may be modified by fractional crystallization, contamination with crustal melts, magma mixing, and degassing. Following its ascent through the crust, magma may feed a volcano and be extruded as lava, or it may solidify underground to form an intrusion, such as a ... [...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] |
