十万个为什么·科学阅读30篇（4）

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为什么某些熔岩管在喷发后数十年仍保持温暖？

Lava tubes form when the outer surface of a lava flow cools and hardens while molten rock continues flowing beneath.
After the eruption ends, residual heat slowly escapes through cracks and porous basalt walls.
These tubes act like natural insulation because basalt has low thermal conductivity and traps infrared radiation effectively.
Scientists measure temperatures inside ancient tubes using infrared sensors and find readings up to 20°C above ambient air.
The slow cooling process can last thirty years or more depending on tube diameter and surrounding rock density.
This retained heat supports unique microbial communities that thrive in stable, warm, dark environments.
Unlike surface rocks, tube interiors avoid daily temperature swings, enabling long-term thermal inertia.
Geothermal energy researchers study these systems to model subsurface heat retention in volcanic regions.
Some caves even host ice deposits despite warm air—proof of complex local humidity-temperature balance.
Understanding this helps predict geothermal potential and assess hazards near dormant volcanoes.