Volcano Watch: New research sheds light on relationship between Hilina fault system and large earthquakes

The Hilina Pali on Kilauea Volcano’s south flank is visible evidence of the steep Hilina fault system. Beneath this system lies the flat-lying decollement fault that has no visible surface expression but was responsible for the May 4, 2018, magnitude-6.9 earthquake. (Courtesy photo/Ingrid Johanson)

The pali (cliffs) of Kilauea’s south flank are some of the volcano’s most striking features. Reaching up to 500 m (1500 ft) high, they stand out against the otherwise gentle slopes of Hawaii’s most active shield volcano. These pali, including the Hilina Pali, the Holei Pali, and others, are often referred to as faults, and are together called the Hilina fault system. The faults form head-scarps; the above-ground evidence for a large landslide called the Hilina slump.