The ‘stealth’ lavas of Kilauea: the 2014-2015 volcanic crisis in Puna

Abstract:

The 1983 onwards eruption of Kīlauea took a complex turn and changed course in June 2014 when activity switched to a new vent northeast of Pu‘u ‘Ō‘ō. New flows were directed into lower Puna, a district which had not experienced lava since 1845. The new flow was the longest seen in Hawaii in 500 years and in October—November 2015 it threatened buildings in Pāhoa town and critical lifelines (roading, electricity) to a larger population of some 10,500 people in lower Puna.

The behavior of long-lived slow-moving flows of this type is exceptionally difficult to predict over time and the lava advanced as narrow lobes, typically only a few inches high and feet-wide, guided by small changes in ground slope and local barriers, before widening and thickening over time scales of days. New lobes have then broken out either from the front or margins of the flows, often taking unpredictable paths, and allowing the flows to cover progressively larger areas. The uncertainty as to where the flow would appear next made the human response very challenging. At the same time slow advance gave lots of warning time and has led to both a globally unique set of ‘just-in-time’ measures to mitigation lava impacts and development of a resilient, strong, articulate community. The lava flow retreated back ‘up-slope’ in mid-2015 but remains a hidden threat that could return to threaten Pāhoa and neighboring subdivisions.