Geologist conducts a VLF (very-low-frequency) electromagnetic surve...
Detailed Description
HVO geologist uses a handheld device that can receive very-low-frequency (VLF) radio waves in order to measure lava discharge within a tube. This device, simply called a VLF, measures the shape of the electromagnetic field induced around an active lava tube by transmissions from very-low-frequency radio transmitters scattered around the globe. By making measurements along a transect over an active lava tube, it is possible to derive the cross-sectional area of molten lava within the tube. If the velocity of the lava stream can be determined, such as by measuring it through a nearby skylight (opening in the tube roof) with a radar gun, then the effusion rate can be determined.