Maar

prefLabel
  • Maar
definition
  • Broad, low-relief volcanic crater that is caused by a phreatomagmatic eruption, an explosion caused by groundwater coming into contact with hot lava or magma. A maar characteristically fills with water to form a relatively shallow crater lake.
broader
Abstract from DBPedia
    A maar is a broad, low-relief volcanic crater caused by a phreatomagmatic eruption (an explosion which occurs when groundwater comes into contact with hot lava or magma). A maar characteristically fills with water to form a relatively shallow crater lake which may also be called a maar. The name comes from the local Moselle Franconian dialect of Daun in the Rhineland-Palatinate, Germany, where it derives from Latin mare (sea). Maars are shallow, flat-floored craters that scientists interpret as having formed above diatremes as a result of a violent expansion of magmatic gas or steam; deep erosion of a maar presumably would expose a diatreme. Maars range in size from 60 to 8,000 m (200 to 26,250 ft) across and from 10 to 200 m (33 to 656 ft) deep; most maars commonly fill with water to form natural lakes. Most maars have low rims composed of a mixture of loose fragments of volcanic rocks and rocks torn from the walls of the diatreme.

    マール(英: maar)とは、マグマ水蒸気爆発による火山地形のひとつ。 水が豊富にある場所でマグマ水蒸気爆発が起こって火砕サージを発生し、爆発によって生じた円形の火口の周囲に、少量の火砕サージ堆積物からなる低い環状の丘を形成する。火口底が地下水面より低い場合は、中に水が溜まることが多い。その場合、火口は湖となり、沿岸部では湾入する。通常は1回だけの噴火で形成され(単成火山)、この点で成層火山頂上の火口(湖)とは異なる。

    (Source: http://dbpedia.org/resource/Maar)