In 2018, Kīlauea’s long-lived Pu‘u‘ō‘ō eruption, on the middle East Rift Zone, and decade-old summit lava lake eruption ended. A large lower East Rift Zone eruption partially drained the summit magma reservoir, which caused portions of the unsupported summit caldera floor to collapse.
Kīlauea 2018 lower East Rift Zone Eruption and Summit Collapse
In 2018, Kīlauea’s long-lived Pu‘u‘ō‘ō eruption, on the middle East Rift Zone, and decade-old summit lava lake eruption ended. A large lower East Rift Zone eruption partially drained the summit magma reservoir, which caused portions of the unsupported summit caldera floor to collapse. The event was significant for being the largest lower East Rift Zone eruption and summit collapse in at least 200 years; it was also sadly the most destructive eruption in Hawaii over the same time period.
Collapse of Pu‘u‘ō‘ō and dike migration down Kīlauea East Rift Zone
Increased pressurization of Kīlauea’s magmatic system, indicated by high lava lake levels at the summit and increased rates of ground tilt, likely enabled magma to intrude past Pu‘u‘ō‘ō, a vent that had been erupting nearly continuously on Kīlauea’s middle East Rift Zone since 1983. Pu‘u‘ō‘ō shield collapsed on April 30, 2018, forming a crater; this reflected a sub-surface change that allowed a dike body of magma to move below ground towards the lower East Rift Zone.
Progression of the dike down-rift was reflected in the similar spatial progression of earthquake activity, and on May 3, 2018, lava broke out onto the surface within Leilani Estates, a residential subdivision on the lower East Rift Zone of Kīlauea. Early in the eruptive sequence, several fissure vents opened that were slightly offset from the rift zone, where they began erupting spatter and sticky, viscous, lava flows that did not travel far from the vents they were being erupted from. Geochemical analyses indicated that this initially erupted lava had been stored and cooling beneath the surface of the rift zone for decades.
A magnitude 6.9 earthquake occurred on May 4, 2018 and dilated the rift zone by approximately 5 m (16 ft). The earthquake was likely caused by pressure induced by the dike continuing to intrude into the lower East Rift Zone.
As the dike progressed into the lower East Rift Zone, and during the initial days of the eruption there, the lava lake that had been active within Halema‘uma‘u crater at Kīlauea’s summit began to drain. By May 10, 2018, the lava lake had dropped out of view, and rockfalls were common in the summit vent area, generating small ashy plumes. On May 16, the first of a dozen minor explosive events occurred, with a plume consisting of ash-sized fragments of the crater walls (no fresh lava was present) and small crater-wall blocks; slightly elevated summit sulfur dioxide (SO2) emissions accompanied these events. The USGS Hawaiian Volcano Observatory (HVO) abandoned observatory buildings near Kīlauea summit, as frequent earthquakes in the summit region began to damage the structures.
Change in eruption dynamics and focus on fissure 8
In mid-May of 2018, the character of the eruption on the lower East Rift Zone changed. Hotter and more fluid magma began to erupt from multiple vents, which allowed lava flows to travel faster and farther; geochemical analyses indicated that this change was facilitated by the arrival of “fresher” magma from the summit reservoir. These larger lava flows generally moved in a southeast direction, with lava flows first crossing a highway and entering the ocean the following day—May 19, 2018—near Mackenzie State Recreational area.
In late May, larger areas of the summit began to subside and collapse incrementally as the lower East Rift Zone eruption continued to slowly drain Kīlauea’s summit magma chamber. The collapses and associated activity progressed cyclically; earthquakes in the summit region would increase until the unsupported floor of the caldera dropped—in a piston-like manner—down by several meters (several yards), after which earthquake activity would diminish. Over the next day or so, the earthquake activity would progressively increase again. Up to 700 earthquakes equal to or greater than magnitude 4 occurred between each summit collapse event, which culminated in a near-daily magnitude 5.2–5.4 earthquake.
On May 27, 2018, activity returned to one of the fissure vents that had been active earlier in the eruption—fissure 8. By the following day, eruptive activity became focused at fissure 8, where an 80-m-high (260 ft) lava fountain rapidly produced a tephra cone. A channelized lava flow from fissure 8 travelled in a northeast direction to enter the ocean at Kapoho Bay on June 3, 2018.
Near the coast, the fissure 8 lava flow field expanded, entering the ocean in numerous locations, and forming a large lava delta. Eventually, the direction of the channelized flow shifted southward, around the west side of Kapoho Crater, and small ocean entries proceeded southwest along the coast approaching Pohoiki Bay.
Kīlauea’s summit continued to incrementally collapse as the lower East Rift Zone eruption slowly siphoned magma from the summit storage system. In total, 62 collapse events occurred. Several hours after the floor of Kīlauea’s summit experienced a collapse, the lava eruption rate at fissure 8 in the lower East Rift Zone would surge, reflecting increased pressurization of Kīlauea’s magma system as a result of the summit collapse event.
The last collapse event occurred at Kīlauea’s summit on August 2, 2018, and, on August 4, 2018, lava eruption rates and SO2 emission rates at fissure 8 in the lower East Rift Zone greatly decreased. Lava was intermittently visible within the fissure 8 cone over the next month, and ocean entries slowed and eventually ceased by August 21, 2018. Active lava was last visible within fissure 8 on September 5, 2018.
Impacts, significance, and interpretations
Locally, the destruction caused by Kīlauea’s 2018 lower East Rift Zone eruption was unprecedented in modern history. An area of 35.5 square kilometers (over 8,700 acres) was covered with lava, which includes the addition of 875 acres of new land created near the eastern extent of the Island of Hawai‘i. Residents were displaced as lava covered over 700 structures and 48 kilometers (30 miles) of road; other uncovered properties in the lower East Rift Zone became inaccessible as lava flows blocked access.
Much of the State of Hawaii, and areas as far as Guam, were also impacted by vog—volcanic air pollution caused by interaction of the atmosphere with nearly 200,000 metric tons of SO2 being emitted each day of the 2018 lower East Rift Zone eruption. These emission rates are the largest ever measured on Kīlauea, representing a total of 10 Mt (megatonnes, or millions of tonnes) of SO2 between May and early August 2018.
After Kīlauea summit lava lake drained and the summit began to collapse in 2018, concern grew regarding the potential for violent explosions, as had occurred during a similar (but smaller) sequence of events at Kīlauea summit in 1924. However, the 2018 events proceeded passively at the summit, with none of the anticipated violent explosions occurring. Whereas models for the 1924 events suggested that interaction of hot rocks and groundwater incited explosions, the primarily lithic-ash (composed of older rock material, as opposed to fresh lava) plumes and slightly increased SO2 emissions during the 2018 events suggested that magmatic gas was a driver.
At Kīlauea summit, infrastructure within Hawai‘i Volcanoes National Park was damaged by the more than 60,000 earthquakes that accompanied the summit collapse events. In total, the summit caldera deepened by more than 500 meters (1600 feet) and the volume of summit collapse approximately half the volume of lava erupted in the lower East Rift Zone—approximately 0.8 cubic kilometers (0.2 cubic miles) of summit collapse compared to 1.5 cubic kilometer (0.4 cubic miles) of lava erupted.
The large volume of Kīlauea summit collapse and lower East Rift Zone eruption in 2018 was likely facilitated by the relatively low elevation of the 2018 vents, over 900 meters (3,000 feet) lower than the summit. Once a pathway was established for magma to be transported from the summit to fissure 8, named “Ahu‘ailā‘au” after the eruption, hydrostatic (magmastatic) pressure enabled the eruption to continue at a high rate not observed previously on Kīlauea.
Modern monitoring techniques were applied to Kīlauea’s 2018 events and enabled efficient hazard assessment. Changes in chemistry of lava eruption from Kīlauea’s lower East Rift Zone in 2018 were measured in near real-time and heralded changes in eruption style and associated hazards. Detailed simultaneous monitoring of the summit and East Rift Zone eruption site demonstrated the hydraulic connection between the two; monitoring crews were able to anticipate increased lower East Rift Zone eruption site hazards associated with lava surges caused by summit collapse events. New monitoring techniques were developed, such as use of Unoccupied Aircraft Systems (UAS) for monitoring vent and lava flow dynamics and measuring volcanic gas emissions; digital elevation models were updated during the eruption to more accurately forecast lava flow paths. This comprehensive monitoring regime advanced knowledge of Kīlauea’s magma plumbing system and eruption dynamics and allowed for better hazard assessments.
Following the summit collapse and lower East Rift Zone eruption of Kīlauea in 2018, the volcano entered a brief period of quiescence. Water that appeared in the base of the collapsed area in July 2019 grew into a large lake that was monitored with many of the techniques developed during Kīlauea’s 2008–2018 summit lava lake and 2018 eruption. In December 2020, an eruption began within Halema‘uma‘u at the summit. The erupting lava quickly vaporized the water lake and replaced it with a larger lava lake. The lava lake filled 229 meters (751 feet) of the 2018 collapsed area and was active through May 2021.
Resources Relating to Kīlauea's 2018 Activity
- Preliminary summary of Kīlauea Volcano's 2018 lower East Rift Zone eruption and summit collapse (pdf)
- 8 May 2018 – Preliminary Analysis of Current Explosion Hazards at the Summit of Kīlauea Volcano (pdf)
- 29 June 2018 – Volcanic Hazard at the Summit of Kīlauea Update (pdf)
- 29 June 2018 – Frequently Asked Questions about Deformation at Kīlauea's Summit (pdf)
- 15 July 2018 – Preliminary analysis of the Kīlauea lower East Rift Zone eruption: Fissure 8 prognosis and ongoing hazards (pdf)
- Chronology of Events for 2018 Kīlauea activity (pdf)
- Frequently Asked Questions about Kīlauea Volcano's Summit Earthquakes (pdf)
- Video of Feb. 4, 2020, presentation: "Seismicity of the 2018 Kīlauea Volcano eruption"
- Video of Jan. 30, 2020, presentation: "What can lava tell us? Deciphering Kīlauea's 2018 eruption through chemistry"
- Video of Jan. 30, 2020, presentation: "Kīlauea lower East Rift Zone 2019: quiet but insightful"
- Video of Jan. 21, 2020, presentation: "Transitions: What's next for HVO and the volcanoes it monitors?"
- Video of May 9, 2018, Community meeting held at Hawai‘i Volcanoes National Park
- USGS geonarrative describing Kīlauea Volcano's 2018 events
Kīlauea 2018 Eruption Data
- Damby, D.E., Peek, S., Lerner, A.H., and Elias, T., 2018, Volcanic ash leachate chemistry from increased 2018 activity of Kīlauea Volcano, Hawaii: U.S. Geological Survey data release.
- Hawaiian Volcano Observatory staff, 2018, Preliminary map of the 2018 lower East Rift Zone eruption of Kīlauea Volcano, Island of Hawai‘i: U.S. Geological Survey.
- Lee, R.L., Gansecki, C., Lundblad, S., Mills, P., Adams, D.T., Conrey, R., and Wagoner, L., 2019, Whole-rock and glass chemistry of lava samples collected during the 2018 Lower East Rift Zone eruption of Kīlauea: U.S. Geological Survey data release.
- Mosbrucker, A.R., Zoeller, M.H. & Ramsey, D.W., 2020, Digital elevation model of Kīlauea Volcano, Hawai‘i, based on July 2019 airborne lidar surveys: U.S. Geological Survey data release.
- Patrick, M.R., Dietterich, H., Lyons, J., Diefenbach, A., Parcheta, C., Anderson, K., Namiki, A., Sumita, I., Shiro, B., and Kauahikaua, J., 2019, Cyclic lava effusion during the 2018 eruption of Kīlauea Volcano: data release: U.S. Geological Survey data release.
- Patrick, M.R., Younger, E.F., and Tollett, W., 2019, Lava level and crater geometry data during the 2018 lava lake draining at Kīlauea Volcano, Hawaii: U.S. Geological Survey data release.
- Zoeller, M.H., Perroy, R.L., Wessels, R.L., Fisher, G.B., Robinson, J.E., Bard, J.A., Peters, J., Mosbrucker, A.R. and Parcheta, C., 2020, Geospatial database of the 2018 lower East Rift Zone eruption of Kīlauea Volcano, Hawai‘i>: U.S. Geological Survey Data Release.
- Fact Sheet, Kīlauea – An Explosive volcano in Hawai‘i
- Anderson, K.R., Johanson, I.A., Patrick, M.R., Gu, M., Segall, P., Poland, M.P., Montgomery-Brown, E., and Miklius, A., 2019, Magma reservoir failure and the onset of caldera collapse at Kīlauea Volcano in 2018: Science, v. 366, no. 6470, eaaz1822.
- Butler, R., 2019, Volcanic earthquake foreshocks during the 2018 collapse of Kīlauea Caldera: Geophysical Journal International, v. 220, no. 1, p. 71-78.
- Gansecki, C., Lee, R.L., Shea, T., Lundblad, S.P., Hon, K., and Parcheta, C., 2019, The tangled tale of Kīlauea's 2018 eruption as told by geochemical monitoring: Science, v. 366, no. 6470, eaaz0147.
- Kauahikaua, J. and Trusdell, F., 2020, Have humans influenced volcanic activity on the lower East Rift Zone of Kīlauea Volcano? A publication review: U.S. Geological Survey Open-File Report 2020–1017, 17 p.
- Kehoe, H.L., Kiser, E.D., and Okubo, P.G., 2019, The rupture process of the 2018 Mw 6.9 Hawai‘i earthquake as imaged by a genetic algorithm-based back-projection technique: Geophysical Research Letters, v. 46, no. 5, March 16, p. 2467-2474.
- Liu, C., Lay, T., and Xiong, X., 2018, Rupture in the 4 May 2018 MW 6.9 earthquake seaward of the Kīlauea East Rift Zone fissure eruption in Hawaii: Geophysical Research Letters, v. 45, no. 18, September 28, p. 9508-9515.
- McMurtry, G.M., Dasilveira, L.A., Horn, E.L., DeLuze, J.R., and Blessing, J.E., 2019, High 3He/4He ratios in lower East Rift Zone steaming vents precede a new phase of Kīlauea 2018 eruption by 8 months: Nature, Scientific Reports, v. 9, August 14, article no. 11860.
- Neal, C.A., and others, 2019, The 2018 rift eruption and summit collapse of Kīlauea Volcano: Science, v. 363, no. 6425, p. 367-374.
- Olivier, G., Brenguier, F., Carey, R., Okubo, P., and Donaldson, C., 2019, Decrease in seismic velocity observed prior to the 2018 eruption of Kīlauea Volcano with ambient seismic noise interferometry: Geophysical Research Letters, v. 46, no. 7, April 16, p. 3734-3744.
- Patrick, M.R., Dietterich, H.R., Lyons, J.J., Diefenbach, A.K., Parcheta, C., Anderson, K.R., Namiki, A., Sumita, I., Shiro, B., and J.P. Kauahikaua, 2019, Cyclic lava effusion during the 2018 eruption of Kīlauea Volcano: Science, v. 366, no. 6470, eaay9070.
- Patrick M.R., Orr T., Anderson K., Swanson D.A., 2019, Eruptions in sync: improved constraints on Kīlauea Volcano's hydraulic connection: Earth and Planetary Science Letters, v. 507, p.60-61.
- Soule, A., Heffron, E., Gee, L., Mayer, L., Raineault, N., German, C.R., Lim, D., Zoeller, M.H. and Parcheta, C., 2019, Mapping the lava deltas of the 2018 eruption of Kīlauea Volcano: Oceanography, v. 32, no. 1, p.46-47.
- Wang, K., MacArthur, H.S., Johanson, I., Montgomery?Brown, E.K., Poland, M.P., Cannon, E.C., d'Alessio, M.A., and Bürgmann, R., 2019, Interseismic quiescence and triggered slip of active normal faults of Kīlauea Volcano's south flank during 2001–2018: Journal of Geophysical Research, Solid Earth, v. 124, no. 9, September, p. 9780-9794.
- Wauthier, C., Roman, D.C., and Poland, M.P., 2019, Modulation of seismic activity in Kīlauea's upper East Rift Zone (Hawai‘i) by summit pressurization: Geology, v. 47, no. 9, September 1, p. 820-824.
Maps, Videos, and Photos
- Photograph chronology showing imagery from Kīlauea
- Kīlauea maps
- Videos and short movie clips of Kīlauea
See the table summarizing Kīlauea activity over the past ~200 years here.