24 June 2005 - 1257
![This is a photo of lava in tube inside flow with `a`a crust.](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/full_width/public/thumbnails/image/1257_0.jpg?itok=o5CVAats)
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
Sources/Usage
Public Domain.