Volcano Watch: Kilauea gets weighed in

  • A. Flinders/USGS photo University of Wisconsin-Madison Ph.D. candidate and Hawaiian Volcano Observatory volunteer, Claire Ruggles, measures variations in the strength of gravity (grey box) and precise location (GPS on antenna) on Jan. 7 at the summit of Kilauea.

Measurements of gravity can be used to determine how mass is distributed beneath a volcano. At Kilauea, the Hawaiian Volcano Observatory performs routine microgravity surveys to monitor volcanic activity and to determine changes in gravity. Those changes can indicate whether magma is accumulating in a volcano’s magma reservoir. The surveys measure small gravity changes over time at precisely controlled locations (“benchmarks”) spread across the volcano’s summit region.