Now there's been volcanic action here all right but much too long ago for my taste.

The air keeps replacing itself, more or less, by volcanic action.

The land must have once been torn by fierce volcanic action.

Laurel Hill was formed by volcanic action over 150 million years ago.

He had a theory which I'm beginning to grasp, to do with them forming very fast as a result of volcanic action.

The island was created by volcanic action about 26 mya.

Any volcanic action would surely be down in the hollow and not high among the rocks.

For a moment I thought it was the lava-glow from some volcanic action; but this could not be so.

Nearby, a series of models demonstrates how islands are created by volcanic action.

Your geologists all agree that diamonds result from volcanic action.