Assertion: volcano's shape | /r/HasProperty | cited as the reason
Facets:
value: for force
type: PURPOSE
value: frequently
type: TEMPORAL
Source sentences:
text: The long and enclosed shape of the Rhône Valley, and the Venturi effect of funnelling the air through a narrowing space, is frequently cited as the reason for the speed and force of the mistral, but the reasons are apparently more complex.