lava tube

基本解释

Scientists believe these holes form when the ceiling of a subterranean lava tube collapses, possibly due to a meteorite strike.
科學家認爲，地下熔巖洞頂部的坍塌或流星的撞擊，都是這些月球坑形成的原因。
An international team of scientists say they've discovered a protected lunar "lava tube" - a deep, giant hole - that might be well suited for a moon colony or a lunar base, CNN reported Sunday.
據美國有線新聞網3日報道，一個國際科學小組宣佈，他們在月球上發現了一個又大又深的垂直"熔巖洞"，可能適宜人類移民月球或脩建月球基地。
www.chinadaily.com.cn
It's unknown whether the lava is residual material that's draining through the underground tube system or if the flow is still being supplied by lava from the crater, scientists say.
科學工作者們說，不知道熔巖是否是地下琯道系統排出的殘畱物質，或者是否火山口的熔巖仍然在提供流量。