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Continuous gravity measurements reveal a low-density lava lake at Kīlauea Volcano, Hawai‘i

Earth and Planetary Science Letters

By:
, , , and
DOI: 10.1016/j.epsl.2013.06.024

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Abstract

On 5 March 2011, the lava lake within the summit eruptive vent at Kīlauea Volcano, Hawai‘i, began to drain as magma withdrew to feed a dike intrusion and fissure eruption on the volcanoʼs east rift zone. The draining was monitored by a variety of continuous geological and geophysical measurements, including deformation, thermal and visual imagery, and gravity. Over the first ∼14 hours of the draining, the ground near the eruptive vent subsided by about 0.15 m, gravity dropped by more than 100 μGal, and the lava lake retreated by over 120 m. We used GPS data to correct the gravity signal for the effects of subsurface mass loss and vertical deformation in order to isolate the change in gravity due to draining of the lava lake alone. Using a model of the eruptive vent geometry based on visual observations and the lava level over time determined from thermal camera data, we calculated the best-fit lava density to the observed gravity decrease — to our knowledge, the first geophysical determination of the density of a lava lake anywhere in the world. Our result, 950 +/- 300 kg m-3, suggests a lava density less than that of water and indicates that Kīlaueaʼs lava lake is gas-rich, which can explain why rockfalls that impact the lake trigger small explosions. Knowledge of such a fundamental material property as density is also critical to investigations of lava-lake convection and degassing and can inform calculations of pressure change in the subsurface magma plumbing system.

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Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Continuous gravity measurements reveal a low-density lava lake at Kīlauea Volcano, Hawai‘i
Series title:
Earth and Planetary Science Letters
DOI:
10.1016/j.epsl.2013.06.024
Volume
376
Issue:
15 August
Year Published:
2013
Language:
English
Publisher:
Elsevier
Contributing office(s):
Volcano Science Center
Description:
8 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Earth and Planetary Science Letters
First page:
178
Last page:
185
Country:
United States
State:
Hawai'i
Other Geospatial:
Kilauea Volcano