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24 June 2005 - 1257

Detailed Description

Lava in tube inside flow with `a`a crust. It is often mistakenly claimed that lava tubes form only in flows with pahoehoe crust. In reality, tubes form in basaltic lava flows before they become either pahoehoe or `a`a, because those terms apply only to solid crust, not liquid lava. 1257


Public Domain.