upfilling

He saw that the upfilling of the abyss, whatever might have caused it, had flung them forth; he perceived that the temporary flood which had taken place before once more another terrific down-draft should pour into the gaping chasm, had cast them out, floated by their raft of planks, even as match-straws might be flung and floated on the outburst of a geyser.

Darkness and Dawn George Allan England 1906