A conical hill, often steep, formed by accumulation of solidified fragments of lava
that fall around the vent
of a single basaltic
eruption. The rock fragments, often called cinders or scoria
, are glassy and contain numerous gas bubbles "frozen" into place as magma
exploded into the air and then cooled quickly. Cinder
cones range in size from tens to hundreds of meters tall.
- Cinder cones usually erupt lava flows, either through a breach on one side of the crater or from a vent located on a flank. Lava rarely issues from the top (except as a fountain) because the loose, non cemented cinders are too weak to support the pressure exerted by molten rock as it rises toward the surface through the central vent.
- Perhaps the most famous cinder cone, Paricutin, grew out of a corn field in Mexico in 1943 from a new vent. Eruptions continued for 9 years, built the cone to a height of 424 meters, and produced lava flows that covered 25 km2.
- Cinder cones are commonly found on the flanks of shield volcanoes, stratovolcanoes, and calderas. For example, geologists have identified nearly 100 cinder cones on the flanks of Mauna Kea, a shield volcano located on the Island of Hawai`i (these cones are also referred to as scoria cones and cinder and spatter cones).