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A quake is the result when the surface of a planet, moon or star begins to shake, usually as the consequence of a sudden release of energy transmitted as seismic waves, and potentially with great violence.
The types of quakes include:
An earthquake is a phenomenon that results from the sudden release of stored energy in the Earth's crust that creates seismic waves. At the Earth's surface, earthquakes may manifest themselves by a shaking or displacement of the ground and sometimes cause tsunamis, which may lead to loss of life and destruction of property. An earthquake is caused by tectonic plates (sections of the Earth's crust) getting stuck and putting a strain on the ground. The strain becomes so great that rocks give way and fault lines occur.
A moonquake is the lunar equivalent of an earthquake (i.e., a quake on the Moon) although moonquakes are caused in different ways. They were first discovered by the Apollo astronauts. The largest moonquakes are much weaker than the largest earthquakes, though their shaking can last for up to an hour, due to fewer attenuating factors to damp seismic vibrations. [1]
Information about moonquakes comes from seismometers placed on the Moon from 1969 through 1972. The instruments placed by the Apollo 12, 14, 15 and 16 missions functioned perfectly until they were switched off in 1977.
There are at least four kinds of moonquake:
The first three kinds of moonquakes mentioned above tend to be mild; however, shallow moonquakes can register up to mB=5.5 on the body-wave magnitude scale. [7] Between 1972 and 1977, 28 shallow moonquakes were observed. Deep moonquakes tend to occur within isolated kilometer-scale patches, sometimes referred to as nests or clusters. [8]
A marsquake is a quake that occurs on the planet Mars. A 2012 study suggests that marsquakes may occur every million years. [9] This suggestion is related to evidence found then of Mars's tectonic boundaries. [10] A tremor believed to be a possible marsquake was first measured by NASA's InSight lander on April 6, 2019, which was one of the lander's key science goals. [11]
A venusquake is a quake that occurs on the planet Venus.
A venusquake may have caused a new scarp and a landslide to form. An image of the landslides was taken in November 1990 during the first flight around Venus by the Magellan spacecraft. Another image was taken on July 23, 1991 as the Magellan revolved around Venus for the second time. Each image was 24 kilometres (15 mi) across and 38 kilometres (24 mi) long, and was centered at 2° south latitude and 74° east longitude. The pair of Magellan images shows a region in Aphrodite Terra, within a steeply sloping valley that is cut by many fractures (faults). [12]
A sunquake is a quake that occurs on the Sun.
Seismic waves produced by sunquakes occur in the photosphere and can travel at velocities of 35,000 kilometres per hour (22,000 mph) for distances up to 400,000 kilometres (250,000 mi) before fading away. [13]
On July 9, 1996, a sunquake was produced by an X2.6 class solar flare and its corresponding coronal mass ejection. According to researchers who reported the event in Nature , this sunquake was comparable to an earthquake of a magnitude 11.3 on the Richter scale. That represents a release of energy approximately 40,000 times greater than that of the devastating 1906 San Francisco earthquake, and far greater than that of any earthquake ever recorded. Such an event contains the energy of 100–110 billion tons of TNT or 2 million modest sized nuclear bombs. It is unclear how such a relatively modest flare could have liberated sufficient energy to generate such powerful seismic waves. [13] [14]
The ESA and NASA spacecraft SOHO records sunquakes as part of its mission to study the Sun.
A starquake is an astrophysical phenomenon that occurs when the crust of a neutron star undergoes a sudden adjustment, analogous to an earthquake on Earth [15] . Starquakes are thought to result from two different mechanisms. One is the huge stresses exerted on the surface of the neutron star produced by twists in the ultra-strong interior magnetic fields. A second cause is a result of spindown. As the neutron star loses linear velocity due to frame-dragging and by the bleeding off of energy due to it being a rotating magnetic dipole, the crust develops an enormous amount of stress. Once that exceeds a certain level, it adjusts itself to a shape closer to non-rotating equilibrium: a perfect sphere. The actual change is believed to be on the order of micrometers or less, and occurs in less than a millionth of a second.
The largest recorded starquake was detected on December 27, 2004 from the ultracompact stellar corpse SGR 1806-20. [16] The quake, which occurred 50,000 light years from Earth, released gamma rays equivalent to 1037 kW. Had it occurred within a distance of 10 light years from Earth, the quake could have triggered a mass extinction. [17]
A mercuryquake is a quake that occurs on Mercury. In 2016 it has been suggested that quakes might happen on Mercury due to the planet's contraction as the interior cools, impact vibrations or from heat or possibly magma rising from the core and mantle. It has not been measured or proved yet due to the fact that no probes have landed on its surface.
An earthquake – also called a quake, tremor, or temblor – is the shaking of the surface of Earth resulting from a sudden release of energy in the lithosphere that creates seismic waves. Earthquakes can range in intensity, from those that are so weak that they cannot be felt, to those violent enough to propel objects and people into the air, damage critical infrastructure, and wreak destruction across entire cities. The seismic activity of an area is the frequency, type, and size of earthquakes experienced over a particular time. The seismicity at a particular location in the Earth is the average rate of seismic energy release per unit volume. The word tremor is also used for non-earthquake seismic rumbling.
Seismology is the scientific study of earthquakes and the generation and propagation of elastic waves through the Earth or other planetary 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 microseism, atmospheric, and artificial processes such as explosions and human activities. A related field that uses geology to infer information regarding past earthquakes is paleoseismology. A recording of Earth motion as a function of time, created by a seismograph is called a seismogram. A seismologist is a scientist working in basic or applied seismology.
The following is a timeline of Solar System astronomy and science. It includes the advances in the knowledge of the Earth at planetary scale, as part of it.
A seismic wave is a mechanical wave of acoustic energy that travels through the Earth or another planetary body. It can result from an earthquake, volcanic eruption, magma movement, a large landslide, and a large man-made explosion that produces low-frequency acoustic energy. Seismic waves are studied by seismologists, who record the waves using seismometers, hydrophones, or accelerometers. Seismic waves are distinguished from seismic noise, which is persistent low-amplitude vibration arising from a variety of natural and anthropogenic sources.
A lander is a spacecraft that descends towards, then comes to rest on the surface of an astronomical body other than Earth. In contrast to an impact probe, which makes a hard landing that damages or destroys the probe upon reaching the surface, a lander makes a soft landing after which the probe remains functional.
A planetary core consists of the innermost layers of a planet. Cores may be entirely solid or entirely liquid, or a mixture of solid and liquid layers as is the case in the Earth. In the Solar System, core sizes range from about 20% to 85% of a planet's radius (Mercury).
SGR 1806−20 is a magnetar, a type of neutron star with a very powerful magnetic field, that was discovered in 1979 and identified as a soft gamma repeater. SGR 1806−20 is located about 13 kiloparsecs (42,000 light-years) from Earth on the far side of the Milky Way in the constellation of Sagittarius. It has a diameter of no more than 20 kilometres (12 mi) and rotates on its axis every 7.5 seconds (30,000 kilometres per hour (19,000 mph) rotation speed at the surface). As of 2016, SGR 1806-20 is the most highly magnetized object ever observed, with a magnetic field over 1015 gauss (G) (1011 tesla) in intensity (compared to the Sun's 1–5 G and Earth's 0.25–0.65 G).
The geology of Venus is the scientific study of the surface, crust, and interior of the planet Venus. Of all the other planets in the Solar System, it is the one nearest to Earth and most like it in terms of mass, but has no magnetic field or recognizable plate tectonic system. Much of the ground surface is exposed volcanic bedrock, some with thin and patchy layers of soil covering, in marked contrast with Earth, the Moon, and Mars. Some impact craters are present, but Venus is similar to Earth in that there are fewer craters than on the other rocky planets that are largely covered by them. This is due in part to the thickness of the Venusian atmosphere disrupting small impactors before they strike the ground, but the paucity of large craters may be due to volcanic re-surfacing, possibly of a catastrophic nature. Volcanism appears to be the dominant agent of geological change on Venus. Some of the volcanic landforms appear to be unique to the planet. There are shield and composite volcanoes similar to those found on Earth. Given that Venus has approximately the same size, density, and composition as Earth, it is plausible that volcanism may be continuing on the planet today, as demonstrated by recent studies.
Cleopatra, initially called Cleopatra Patera, is an impact crater on Venus, in Maxwell Montes.
Seismic magnitude scales are used to describe the overall strength or "size" of an earthquake. These are distinguished from seismic intensity scales that categorize the intensity or severity of ground shaking (quaking) caused by an earthquake at a given location. Magnitudes are usually determined from measurements of an earthquake's seismic waves as recorded on a seismogram. Magnitude scales vary on what aspect of the seismic waves are measured and how they are measured. Different magnitude scales are necessary because of differences in earthquakes, the information available, and the purposes for which the magnitudes are used.
A marsquake is a quake which, much like an earthquake, would be a shaking of the surface or interior of the planet Mars as a result of the sudden release of energy in the planet's interior, such as the result of plate tectonics, which most quakes on Earth originate from, or possibly from hotspots such as Olympus Mons or the Tharsis Montes. The detection and analysis of marsquakes could be informative to probing the interior structure of Mars, as well as identifying whether any of Mars's many volcanoes continue to be volcanically active.
Having a mean density of 3,346.4 kg/m3, the Moon is a differentiated body, being composed of a geochemically distinct crust, mantle, and planetary core. This structure is believed to have resulted from the fractional crystallization of a magma ocean shortly after its formation about 4.5 billion years ago. The energy required to melt the outer portion of the Moon is commonly attributed to a giant impact event that is postulated to have formed the Earth-Moon system, and the subsequent reaccretion of material in Earth orbit. Crystallization of this magma ocean would have given rise to a mafic mantle and a plagioclase-rich crust.
The Hollow Moon and the closely related Spaceship Moon are pseudoscientific hypotheses that propose that Earth's Moon is either wholly hollow or otherwise contains a substantial interior space. No scientific evidence exists to support the idea; seismic observations and other data collected since spacecraft began to orbit or land on the Moon indicate that it has a thin crust, extensive mantle and small, dense core, although overall it is much less dense than Earth.
The Cerberus Fossae are a series of semi-parallel fissures on Mars formed by faults which pulled the crust apart in the Cerberus region. They are 1235 km across and centered at 11.28 °N and 166.37 °E. Their northernmost latitude is 16.16 °N and their southernmost latitude 6.23 °N. Their easternmost and westernmost longitudes are 174.72 °E and 154.43 °E, respectively. They can be seen in the Elysium quadrangle.
The geology of solar terrestrial planets mainly deals with the geological aspects of the four terrestrial planets of the Solar System – Mercury, Venus, Earth, and Mars – and one terrestrial dwarf planet: Ceres. Earth is the only terrestrial planet known to have an active hydrosphere.
Lunar seismology is the study of ground motions of the Moon and the events, typically impacts or moonquakes, that excite them.
The Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) mission was a robotic lander designed to study the deep interior of the planet Mars. It was manufactured by Lockheed Martin Space, was managed by NASA's Jet Propulsion Laboratory (JPL), and two of its three scientific instruments were built by European agencies. The mission launched on 5 May 2018 at 11:05:01 UTC aboard an Atlas V-401 launch vehicle and successfully landed at Elysium Planitia on Mars on 26 November 2018 at 19:52:59 UTC. InSight was active on Mars for 1440 sols.
The Seismic Experiment for Interior Structure (SEIS) is a seismometer and the primary scientific instrument on board the InSight Mars lander launched on 5 May 2018 for a landing on 26 November 2018; the instrument was deployed to the surface of Mars on 19 December. SEIS is expected to provide seismic measurements of marsquakes, enabling researchers to develop 3D structure maps of the deep interior. Better understanding the internal structure of Mars will lead to better understanding of the Earth, Moon, and rocky planetary bodies in general.
The Passive Seismic Experiment Package (PSEP) was a scientific experiment deployed on the lunar surface by the astronauts of Apollo 11 as part of the Early Apollo Surface Experiments Package (EASEP). The experiment's goal was to determine the structure, tectonic activity, physical nature, and composition of the Moon. PSEP was the first seismometer to be deployed on a planetary body other than Earth.
Seismic velocity structure is the distribution and variation of seismic wave speeds within Earth's and other planetary bodies' subsurface. It is reflective of subsurface properties such as material composition, density, porosity, and temperature. Geophysicists rely on the analysis and interpretation of the velocity structure to develop refined models of the subsurface geology, which are essential in resource exploration, earthquake seismology, and advancing our understanding of Earth's geological development.
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