Assertion: volcano's slope | /r/CapableOf | steepen with elevation
Facets:
value: gradually
type: MANNER
value: before flattening near the summit
type: TEMPORAL
Source sentences:
text: Shield volcanoes feature a gentle (usually 2° to 3°) slope that gradually steepens with elevation (reaching approximately 10°) before eventually flattening near the summit, forming an overall upwardly convex shape.