Geologists conduct a VLF (very low frequency) survey across the epi...
![HVO geologists conduct a VLF (very low frequency) survey across the...](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/full_width/public/vhp_img4403.jpg?itok=IKhYqS-J)
Detailed Description
HVO geologists conduct a VLF (very low frequency) survey across the episode 61g lava tube to measure the depth and cross-sectional area of lava flowing within the tube.