Student research into fault system following Kīlauea’s 2018 eruption yields important findings
UH Hilo students, working closely with scientists, have played important roles in collecting and analyzing the data following the 2018 eruption. Thus far, two groups of students have traveled to scientific conferences to present their findings.
Since the 2018 eruption, the Department of Geology at the University of Hawai‘i at Hilo has partnered with Hawai‘i Volcano Observatory (HVO) scientists to do “old school” leveling where it is the best approach available. UH Hilo has capable and enthusiastic geology students, and over the years many have volunteered to measure the cracks and faults.
The Koa‘e fault system connects Kīlauea’s East and Southwest Rift Zones south of the caldera. Faults here appear as low cliffs or “scarps” along Hilina Pali Road in Hawai‘i Volcanoes National Park. These fault-cliffs slip during major earthquakes, such as those of May 4, 2018, near the beginning of Kīlauea’s 2018 eruption.
Although newer techniques are now being used, for decades geologists have used an older approach called “leveling” to measure this movement. Leveling remains a valuable geodetic method some 170 years after it was invented, and U.S. Geological Survey (USGS) HVO scientists have used it for decades to study Hawai‘i Island volcanoes, with important results.
UH Hilo students, working closely with the scientists, have played important roles in collecting and analyzing the data through conducting leveling research following the 2018 lava event. Thus far, two groups of students have traveled to scientific conferences to present their findings.
“We are proud of the contributions these new researchers have made to the Island of Hawai‘i community and the wider world of science,” says UH Hilo Professor of Geology Steve Lundblad, who recently penned a column about the research.
Findings
Leveling requires teams of people working along an established grid in the field, and it’s time-intensive. Telescopes aimed at hand-held, graded stadia rods, essentially giant vertical rulers, at specifically positioned field stations.
USGS scientists first began leveling along the Koa‘e faults in the 1960s, providing a long-standing record of data and field stations already in place. Around each leveling station is an array of subsidiary “crack stations,” allowing measurement across individual Koa‘e faults and their related ground cracks.
When the Koa‘e faults move, they either slide vertically or open to create a deep crack. A dramatic example of opening was the Hilina Pali Road 2018 faulting near Kulanaokuaiki campground, which split the road. The prominent slope the road ascends is a result of repeated fault movement over several hundred years. Shortly after the end of the 2018 eruption, leveling revealed that the rates of change along the Koa‘e faults quickly returned to the much slower normal pace.
“We’ve learned several important things about the behavior of the fault system from the on-going Koa‘e leveling campaign,” writes Lundblad about the work of the scientists and students. “Most of the relief along these cliffs is created by large events. The faults are also very efficient ‘earth movers.’ Very few new cracks formed as a result of the large geologic events of 2018.”
