Question: In what year did the eruption occur that laid down the lava upon which a famous forest visible from the Tenjō-Yama Park Mt. Kachi Kachi Ropeway? 
Sentence (from "Aokigahara"): Parts of Aokigahara are very dense, and the porous lava absorbs sound, helping to provide visitors with a sense of solitude.
Relevant evidence: No