Geologist conducts a VLF (very-low-frequency) electromagnetic surve...

HVO geologist conducts a VLF (very-low-frequency) electromagnetic s...

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.


Image Dimensions: 3264 x 2448

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