Task: Class Definition Understanding (ontology: Earth_Environment/EnvironmentOntology)

Which of the following definitions best describes 'pseudocrater'?

A. A the concept formed by a volcano, within which occurs a vent (or vents) from which magma erupts as gases, lava, and ejecta.
B. A broad, low relief crater that results from a phreatic eruption or explosion caused by groundwater contact with hot lava or magma. The the concept typically fills with water to form a relatively shallow crater lake.
C. A feature formed by the collapse of land following a volcanic eruption.
D. A volcanic landform which resembles a true volcanic crater, but differs in that it is not an actual vent from which lava has erupted. A the concept is characterised by the absence of any magma conduit which connects below the surface of the earth. Pseudocraters are formed by steam explosions as flowing hot lava crosses over a wet surface, such as a swamp, a lake, or a pond. The explosive gases break through the lava surface in a manner similar to a phreatic eruption, and the tephra builds up crater-like forms which can appear very similar to real volcanic craters.

Answer: A volcanic landform which resembles a true volcanic crater, but differs in that it is not an actual vent from which lava has erupted. A the concept is characterised by the absence of any magma conduit which connects below the surface of the earth. Pseudocraters are formed by steam explosions as flowing hot lava crosses over a wet surface, such as a swamp, a lake, or a pond. The explosive gases break through the lava surface in a manner similar to a phreatic eruption, and the tephra builds up crater-like forms which can appear very similar to real volcanic craters.