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 …

A maar is a volcanic crater that forms when magma contacts groundwater to produce a steam explosion.

Maar, small crater blasted by a low-temperature volcanic explosion and not associated with a volcanic cone. The rim of ejected fragmental material around the crater often is very low and inconspicuous.

Apr 17, 2023 · Maars and tuff rings are low-standing volcanoes with wide, bowl-shaped craters. They commonly have a donut-like profile, and may be breached. Their low edifices consist of shallowly-dipping deposits of tuff made mostly of ash and angular, nonvesicular pebble-sized pyroclasts (lapilli).

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.

Feb 28, 2025 · In contrast, a maar is a relatively small, broad, low-relief volcanic crater created by a phreatomagmatic explosion, which occurs when magma interacts with groundwater. Essentially, a caldera is a large-scale collapse feature, while a maar is a smaller, explosion-generated crater.

Jan 7, 2024 · What Are Maars and How Do They Form? Maars are shallow, nearly rounded to oval bowl-shaped volcanic craters surrounded by low rims of fragmental debris or pyroclasts. These landforms are hydrovolcanic and usually monogenetic.

May 15, 2018 · A maar crater is the top of a much larger subsurface diatreme structure produced by phreatomagmatic explosions and the size and shape of the crater reflects the growth history of that structure during an eruption.

Oct 26, 2021 · Maars are shallow craters formed by phreatomagmatic explosions: interactions between magma and groundwater (in our case permafrost). As magma comes into close proximity with permafrost it creates steam, thus, increasing its volume and building pressure until it is released through a violent explosion.

Apr 11, 2025 · Maar NASA's maar data provide details on how and where they form as well as clues to Earth's climate record and change. In a number of historically and currently volcanically active regions on Earth are low-lying craters often filled with water called maars.