Lava — molten rock that flows onto the Earth's surface during a volcanic eruption; it solidifies into rock when cooled.
火山が噴火して溶岩が麓まで流れた。
The volcano erupted and lava flowed down to the foothills.
溶岩が冷えて固まると新しい地形ができることがある。
When lava cools and solidifies, it can form new landforms.
近づくと溶岩の熱で空気が歪んで見えた。
When I got closer, the air looked distorted from the heat of the lava.