fierce volcanic eruption

ans: (a)

(1) Fierce volcanic eruption means that the vent is blocked by acidic lava. Then the eruption will destroyed the volcanic cone and form caldera.Caldera-forming eruptions are the largest eruptions on Earth.

(2)A lava plateau is a flat, wide surface (plateau) that is formed when basic lava comes out of the ground and spreads out very quickly (without any blocking). The lava layers form a lava plateau.

2009-04-04 02:28:03 補充：
typing error ....will destroy