Assertion: caldera | /r/HasProperty | circular
Facets:
value: almost perfectly
type: DEGREE
value: in plan view
type: LOCATION
value: with almost vertical walls
type: OTHER
value: usually
type: DEGREE
Source sentences:
text: Many calderas result from several collapse events and, thus, may present more irregular shapes, while calderas resulting from a single collapse event are usually circular in plan view,
text: A caldera is a circular crater with almost vertical walls.
text: The caldera is actually almost perfectly circular.