### formation | crater:

Caldera
* Most calderas are formed by the collapse of the central part of a cone during great eruptions.
* are among the most spectacular and active volcanic features on Earth
  - basins formed by the collapse of magma in the vents of volcanoes
  - craters formed by the collapse of volcanoes
  - created by the explosive rejuvenation of an inac- tive volcano
* are depressions caused by collapse during volcanic eruptions
  - that form during volcanic eruptions
  - large, basin-shaped depressions
  - natural things
  - often circular or elliptical
  - pits in the ground over one kilometer in diameter
  - some of the most spectacular features on Earth
  - the pit-like scars of shallow lava eruptions
* can range in size from the few miles to tens of miles across.
* develop when magma chamber drains, and the top of the volcano collapses.
* form as a result of collapse following magma withdrawal from the underlying magma chamber
  - of a volcanic structure
  - of an underlying magma chamber
  - when large volumes of magma erupt rapidly
* go through cycles.
* has an ancient and incompatible version of zlib.
* is located on the low part of the coast
  - very well connected, by the modern southern coastal highway , with the Central Valley
* lakes, meandering rivers.

Complex crater
* Many complex craters are widespread in America, Europe, Asia, etc.
* are larger in diameter but shallower in depth.
* have a raised central peak surrounded by a trough and a fractured rim.

### formation | crater:

Impact crater
* Most impact craters have diameters
  - rim diameters
* Some impact craters have bowls
  - occurring on Earth and on other planetary bodies come in close pairs
* are a natural lure for children
  - ubiquitous feature of solid surfaces of celestial objects
  - located in moons
  - rare, but they are found
  - readily visible on the moon's surface
* are the dominant landform
  - most common, pervasive, and scientifically informative landforms on Eros
  - visible on most planets in our solar system
* document external effects on a planet's surface.
* dot the mare surface and one large one partially covers the lava channel.
* form when lumps of rock floating in space collide with the solid planets.
* produce breccia.
* provide insights into the age and geology of a planet's surface.

Lunar crater
* Some lunar craters are much larger than any known on Earth.
* are craters on Earth's Moon.

Maar
* are volcanic basins formed by single explosive eruptions.
* contain a greater proportion of fragmented basement rocks in the ejecta blanket.
* often fill with water and form lakes.

Martian crater
* Most Martian craters have a quite different ejecta pattern.
* can have a morphology that suggests the ground became wet after the meteor impacted.
* show the effects of weathering.

Simple crater
* are bowl-shaped with a raised outer rim
  - what most people think of when they visualize a crater
* occur on Ganymede and Callisto, as they do on the other planets.

Small crater
* are absent because small meteorites burn up or disintegrate in the thin atmosphere.
* cover some regions, and plains with ridges extend over other areas.
* have a relatively short lifespan.