Ejecta

By the ejecta (or will téphras ), the scientists define the objects rejected by the Volcan S which are not Lave during certain explosive eruptions which split up the magma and which fall down more or less vertically out of the crater. Another word, of Greek origin, is used like synonym: will tephra.

These ejecta are classified according to their size in an order ascending:

  • ashes S: particles of less than 2 mms in diameter
  • Lapilli: between 2 and 64 mms diameter
  • Block S and bombs: more than 64 mms in diameter.
The majority of those fall down then by marrying a parabolic trajectory. In addition, the finest particles can reach a sufficient altitude to be pulled by the airstreams at considerable distances.

Each volcanic eruption is characterized by a particular category of ejecta. Thanks to that, the vulcanologist S can define the types of volcanos. These are the products which, by their accumulation, form the volcanic cones gradually.

Other uses of the term

The term of ejecta is also used to indicate the matter crown projected around a crater following the collision of a Météorite on the surface of a Celestial body (planet, natural satellite…).

See too

Seismology

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