As with so many popular beliefs, the answer boils down to: (1) this story is mostly Hollywood BS, but (2) not 100 percent. To get a better handle on things, let’s look at different permutations of the concept, starting with the least plausible and working up.
Virgins have been thrown into volcanoes to appease god(s).
Volcanoes suitable for throwing women into for the most part don't exist. The popular idea is that a volcanic cone has a lake of molten lava inside, perhaps with a rocky promontory jutting out from the rim to provide a convenient spot for victim-flinging. In reality, an erupting volcano typically spews lava up or outward from a cone, vent, or fissure, after which the lava flows laterally along the flattish surfaces nearby.
Virgins have been sacrificed on, if not in, volcanoes.
The mummified remains of numerous murdered Incan children, many of them female, have been found on the upper slopes of volcanoes in the Andes... Archaeologist Johan Reinhard, who led the expeditions that found the Ampato and Llullaillaco mummies, has conjectured that sacrifices at Ampato were intended to stop a volcanic eruption nearby. The site is only reachable when volcanic heat has melted the snow.
Humans, but especially children, have been sacrificed to the gods, or to accompany deceased rulers who presumably were going to join the gods.
This is so abundantly and widely true that it may not seem worth mentioning, but we ought not to let our interest in a particularly baroque sacrificial mode blind us to the larger truth, namely that our species has slaughtered innocents by the uncountable thousands since antiquity.