1. Photograph by C. Nye on 9 May 1994
Alaska Division
of Geological and Geophysical
Surveys
Maar
A maar is a low-relief, broad volcanic crater formed by
shallow explosive eruptions. The explosions are usually
caused by the heating and boiling of groundwater when magma
invades the groundwater table. Maars often fill with
water to form a lake.
2. Photograph by R. Russell on 6 April 1977 Alaska Department
of Fish and Game
Photo 1:
Aerial view toward N of Ukinrek Maars, Alaska;
Lake Becharof at top of photo. Water partially fills the eastern
maar and completely covers a lava dome that was erupted in the
100-m deep crater during a 10-day eruption in 1977. Maar is about
300 m in diameter.
Photo 2:
Eruption column generated by phreatic and
magmatic explosions rises from the larger east maar.
Related photo glossary terms: