Summer 2018 Kilauea Eruption
Our sympathy goes out to those who were impacted by this eruption. We are grateful to everyone who worked so hard during the summer of 2018: Civil Defense, Red Cross, National Guard, FEMA, Hawaii Volcanoes National Park, and especially the USGS. For more details on the eruption, visit the web site of the Hawaiian Volcano Observatory. Below is a brief overview.
Periodically, lava erupts along Kilauea’s East Rift Zone, and heads downhill towards select areas of Puna. In the past few decades, molten lava has moved relatively slowly through Kapoho, Royal Gardens, and Kalapana. This was the pattern everyone was used to.
Volcanic Activity in Early 2018
In the spring of 2018, Kilauea was inflating, indicating that magma was accumulating beneath the volcano. At the summit, Halemaumau lava lake was active, but downrift at Puu Oo, no lava was visible, despite inflation directly below the vent.
The Magma Conduit Widens in May 2018
Many people guessed that there might be a breakout of lava from Puu Oo. But instead, a large earthquake (M 6.9) occurred on 4 May 2018, and the underground conduit between Puu Oo and areas downrift suddenly widened by about 8 feet. This wider conduit allowed magma that had been accumulating under Puu Oo to flow downhill, towards Leilani Estates. The underground magma soon encountered older pods of cooler, stored magma that had been left over from older eruptions (likely including 1955 and 1960.) The new magma pushed out the old magma, which was viscous and therefore moved slowly. Scientists from the Hawaiian Volcano Observatory worked 24/7 to track the eruption; colleagues from the other volcano observatories flew in to lend a hand; Civil Defense ordered residents to evacuate as needed.
Lava Begins to Flow Faster
After the initial pods of older, viscous stored magma had been ejected, the fresh magma was able to erupt. This lava was very fluid and moved quickly, and there was an enormous volume of material, since it included magma stored beneath both Puu Oo and Halemaumau. The eruption centered on Fissure 8, which produced spectacular fountaining, with tephra landing on nearby homes and infrastructure. Lava eventually made its way through Leilani Estates and Kapoho, all the way to the ocean, taking out hundreds of homes that were located downhill.
The Summit Caldera Collapses
Meanwhile, at the summit of Kilauea, magma was draining from beneath Halemaumau and flowing towards Leilani Estates and Kapoho, through the newly widened conduit deep inside the rift zone. After the magma left the summit, the ground above was no longer supported, and the section of the caldera above Halemaumau Crater began to collapse, at the rate of a meter per day. In areas adjacent to the caldera, cracks appeared along roads and trails, and the National Park wisely closed access to everyone except emergency personnel and scientists. UH Hilo Geology staff and students assisted in documenting the cracks for the Park.
UH Hilo Lends a Hand
One problem with the collapse of Kilauea summit was that the Hawaiian Volcano Observatory building, located on the edge of the caldera, developed dangerous cracks, and staff had to evacuate. Fortunately, at the University of Hawaii at Hilo, spring semester had just ended; both the Geology building, and a large laboratory in the building that houses CSAV, were empty for the entire summer, and available for HVO to occupy as their temporary quarters. This arrangement allowed HVO staff to continue operations without interruption, and also led to enhanced collaboration between the Observatory and UH Hilo, via the CSAV Cooperative Research Agreement with the USGS-HVO.
The Eruption Ends, 4 August 2018
Lava flows in Puna stopped in early August (except for minor activity), and the summit collapse came to a finish as well.
Next, the important work of rebuilding infrastructure could begin, but not immediately—for example, thick lava flows in Puna were still too hot to bulldoze over, for creating new roads. In Hawaii Volcanoes National Park, damage had to be carefully assessed, of buildings, roads, and trails, before work could proceed, for safety.