“crater”的概念、定义、翻译、参考文献-科学参考

crater

Astronomy

A bowl-shaped depression on a planetary surface. Craters are usually of either impact or volcanic origin; however, some craters on the satellites of the outer planets may be the result of ice volcanism in which internal heating melts and vaporizes the ice to produce gas explosions and water flows. Volcanic craters tend to be less circular than impact ones, and may be formed either by explosion or collapse. Volcanic craters of purely explosive origin are normally under 1 km in diameter and are usually found at the top of a cone of ejected debris; collapse craters can be more than 100 km across, and may have no outer slope at all. Impact craters have been found on all bodies in the Solar System photographed by space probes except Jupiter’s volcanic satellite Io, but volcanic craters do not seem to exist on the smaller Solar System bodies.

Space Exploration

A bowl-shaped depression in the ground, usually round and with steep sides. Craters are formed by explosive events such as the eruption of a volcano or the impact of a meteorite.
The Moon has more than 300 000 craters over 1 km in diameter, mostly formed by asteroid and meteorite bombardment; similar craters on Earth have mostly been worn away by erosion. Craters are found on all of the other rocky bodies in the Solar System.
Craters produced by impact or by volcanic activity have distinctive shapes, enabling geologists to distinguish likely methods of crater formation on planets in the Solar System. Unlike volcanic craters, impact craters have raised rims and central peaks and are circular, unless the meteorite has an extremely low angle of incidence or the crater has been affected by some later process.

Geology and Earth Sciences

1. General term for a circular, funnel-shaped depression, up to 1 km in diameter, produced by volcanic processes by which gases, tephra, and lava are or have been ejected. Several types are recognized: a crater at the summit of a volcanic cone marks the site of magma degassing and ejection of material; a maar, often occupied by a lake, results from explosive activity; and a caldera is a large volcanic depression greater than 1 km in diameter.
2. Near-circular depression produced by the impact of an extraterrestrial body, e.g. Meteor Crater, Arizona. Meteorite craters are formed by the explosion outward and upward of material compressed and heated strongly by the energy of impact, and so usually are circular at the time they form. They are characterized by topographically raised rims and by ejecta blankets which show inverted stratigraphy with respect to the target rocks. See also shatter cones.

Geography

A circular depression around the vent of a volcano. Craters form the summit of most volcanoes. They occur where lava overflows and hardens or where the walls collapse as the magma sinks down the vent after an eruption. Funnel-shaped craters are typical of stratovolcanoes, while kettle-shaped craters are characteristic of shield volcanoes.

单词	crater
释义	crater Astronomy A bowl-shaped depression on a planetary surface. Craters are usually of either impact or volcanic origin; however, some craters on the satellites of the outer planets may be the result of ice volcanism in which internal heating melts and vaporizes the ice to produce gas explosions and water flows. Volcanic craters tend to be less circular than impact ones, and may be formed either by explosion or collapse. Volcanic craters of purely explosive origin are normally under 1 km in diameter and are usually found at the top of a cone of ejected debris; collapse craters can be more than 100 km across, and may have no outer slope at all. Impact craters have been found on all bodies in the Solar System photographed by space probes except Jupiter’s volcanic satellite Io, but volcanic craters do not seem to exist on the smaller Solar System bodies. Space Exploration A bowl-shaped depression in the ground, usually round and with steep sides. Craters are formed by explosive events such as the eruption of a volcano or the impact of a meteorite. The Moon has more than 300 000 craters over 1 km in diameter, mostly formed by asteroid and meteorite bombardment; similar craters on Earth have mostly been worn away by erosion. Craters are found on all of the other rocky bodies in the Solar System. Craters produced by impact or by volcanic activity have distinctive shapes, enabling geologists to distinguish likely methods of crater formation on planets in the Solar System. Unlike volcanic craters, impact craters have raised rims and central peaks and are circular, unless the meteorite has an extremely low angle of incidence or the crater has been affected by some later process. Geology and Earth Sciences 1. General term for a circular, funnel-shaped depression, up to 1 km in diameter, produced by volcanic processes by which gases, tephra, and lava are or have been ejected. Several types are recognized: a crater at the summit of a volcanic cone marks the site of magma degassing and ejection of material; a maar, often occupied by a lake, results from explosive activity; and a caldera is a large volcanic depression greater than 1 km in diameter. 2. Near-circular depression produced by the impact of an extraterrestrial body, e.g. Meteor Crater, Arizona. Meteorite craters are formed by the explosion outward and upward of material compressed and heated strongly by the energy of impact, and so usually are circular at the time they form. They are characterized by topographically raised rims and by ejecta blankets which show inverted stratigraphy with respect to the target rocks. See also shatter cones. Geography A circular depression around the vent of a volcano. Craters form the summit of most volcanoes. They occur where lava overflows and hardens or where the walls collapse as the magma sinks down the vent after an eruption. Funnel-shaped craters are typical of stratovolcanoes, while kettle-shaped craters are characteristic of shield volcanoes.
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