DefinitionDistinctive featuresDistribution/Types
Oreum contains volcanic cones, parasite volcanoes

Oreum is a tiny volcanic zone that contains a volcanic cone, omnipresent in Jeju Island, except Paekrokdam at the top of Hallasan. The meaning of Oreum includes all the implications of Ak, Bong, Mae and tiny volcanic zones in Jeju Island. Independent volcanic zones or parasite volcanoes in Jeju Island belong to the "Oreum".

Craters should be present

Craters are volcanic zones where the volcanoes had erupted.
A circular cone where no crater is visible is presumed to be flattened at the initial formation stage or sunk in with time. A Crater, from which a volcano erupts, is known to be a prerequisite for the formation of Independent Volcanic zones or parasite volcanoes.

Formed from spouted Volcano

Lava, and other debris of volcanic activities, serve to create lava plateaus, cinder cones, tuff cones, tuff rings, and maar.
A Lava Plateau is a volcanic zone made out of lava.
A Cinder cone is formed out of porous Scoria that comes from the lava, spewing into the air from a volcano and cooling afterwards.
A Tuff is a volcanic zone made out of tiny particles that measure 1/16 - 2mm(or 1/16-4mm). The rock, made out of trass, is called Tuff. Tuff is further divided into Tuff cones and Tuff rings, according to the physical shape of its formation.

What our ancestors in Jeju Islands reffered to as "Oreum" is a small hill or slope, which is covered with a green field or a crater (called "Gumburi") at the peak of a mountain.