Rainfall an unlikely trigger of Kilauea’s 2018 rift eruption

If volcanic eruptions could be forecast from the occurrence of some external process, it might be possible to better mitigate risk and protect lives and livelihoods. Farquharson and Amelung¹ suggested that the 2018 lower East Rift Zone (ERZ) eruption of Kīlauea Volcano—the most destructive eruption in Hawai‘i in at least 200 years²—was triggered by extreme precipitation, which caused increased pore pressure that resulted in mechanical weakening of the volcano. Here we argue that Kīlauea’s 2018 eruption was instead caused by significant pre-eruptive pressurization, that pre-eruptive rainfall was not extreme, and that there is no significant correlation between rain and eruptions at Kīlauea. Understanding the causal mechanisms of volcanic eruptions is vital for hazard assessment and mitigation, and misattribution may compromise monitoring, preparedness, communication and response efforts.