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Geologic Investigations of the Kīlauea Summit Collapse

The 2018 Kīlauea Summit and lower East Rift Zone eruption resulted in 3.5 months of lava discharge, destroying more than 724 structures but fortunately no fatalities. 

Kīlauea geologic investigations: tasks and benefits 2019

This eruption was unprecedented, allowing the first opportunity for the volcano science community to directly observe caldera formation (in the modern instrumented era) because of magma withdrawal from the summit region and its subsequent eruption downslope in the lower East Rift Zone.  Caldera formation was observed through the thousands of M5.3 earthquakes recorded, the GPS instruments in the summit region, and remote sensing technologies (satellites, airborne lidar, and unoccupied aerial systems (UAS)) following the event.  Overall, Halemʻumaʻu pit crater within Kīlauea’s summit caldera was widened by a factor of 2 and deepened by a factor of 3.

Scientific investigations of the current state of Kīlauea are needed to properly interpret the data from the monitoring networks and characterize the ongoing and future threats and hazards to Hawai‘i Volcanoes National Park and surrounding communities.  An integrated program of geophysical, geochemical, and geologic investigations are necessary to understand the shallow magma reservoir status and evolution post-2018. This work will improve our understanding of summit and rift zone structure and magmatic plumbing, the history and likelihood of dangerous explosive eruptions from the summit region, and our understanding of the rift zones where the greatest concentration of risk exists on Kīlauea. Seventeen different research projects are supported by this funding. 

Geologic Investigations Projects: 

Gravity surveys as a means of volcano monitoring:  In 2010, HVO began a new form of volcano monitoring at a station on the rim of Kīlauea’s Halemʻumaʻu crater—continuous gravity recording.  Subtle changes in gravity can signal magma changes below the surface; gravity increases when magma rises to shallower depths beneath a volcano, and gravity decreases when magma drains away. 

Color photograph of instrument
The USGS Hawaiian Volcano Observatory’s Absolute Quantum Gravimeter is undergoing set-up, testing, and calibration before installation at the summit of Kīlauea. USGS image by A. Ellis.

Kīlauea’s summit collapse in May 2018 destroyed this monitoring station, impacting HVO’s ability to provide critical data on subsurface magma changes. Data from a second continuous gravity station, installed at Kīlauea’s down-rift cone Puʻuʻōʻō in 2014, revealed a signal that preceded the collapse of the cone by 1 hour on April 30, 2018—the first signal associated with the onset of the 2018 lower East Rift Zone dike intrusion and eventual eruption. This instrument was recovered and later installed in the post-2018 Kīlauea caldera to monitor potential future eruptive activity, including recording an anomalous signal days before the start of the September 29, 2021, eruption.  Data from this instrument allowed USGS to advise Hawaiʽi Volcanoes National Park (HAVO) on potential hazards and for HAVO to take effective hazard mitigation measures to protect park visitors.

Supplemental funding has greatly enhance HVO’s gravity monitoring program. Funding was used to replace and expand the continuous gravity station network for Kīlauea. New Instruments installed at three additional locations, including Kīlauea’s Southwest Rift Zone, have allowed USGS to become a global leader in gravity monitoring.  The purchase the first federally owned and operated absolute quantum gravity meter, a priority instrument type identified by the National Science and Technology Council’s Subcommittee on Quantum Information Science, will provide stable long-measurements of the absolute gravity field at Kīlauea and form the backbone of HVO’s new continuous monitoring program. This expanded gravity monitoring program offers realistic possibilities of advanced warning in changes of volcanic activity that might not otherwise be available.



Return to 2019 Supplemental Appropriations Activities.


Additional Resources

WATCH Nature's Hawaii’s surprise volcanic eruption: Lessons from Kilauea 2018

Namiki, A., Patrick, M.R., Manga, M., and Houghton, B.F., 2021, Brittle fragmentation by rapid gas separation in a Hawaiian fountain: Nature Geoscience, v. 14, no. 4, p. 242-247.

Houghton, B.F., Cockshell, W.A., Gregg, C.E., Walker, B.H., Kim, K., Tisdale, C.M., and Yamashita, E., 2021, Land, lava, and disaster create a social dilemma after the 2018 eruption of Kīlauea volcano: Nature Communications, v. 12, no. 1, p. 1223.