What Lies Ahead for Kilauea? Perhaps Lo`ihi Knows. Remarkable Parallels Between the 1996 Eruption of Lo`ihi Seamount and the 2018 Kilauea Eruption

Date: 4/26/2019

Time: 11:45 AM

Room: Puget Sound

The cessation of eruptive activity at Kilauea in August 2018 marked the end of 35 years of continuous activity and begs the question of what we can expect with regard to the volcano’s future. This event exhibits remarkable similarity to the 1996 eruption of Lo`ihi seamount, and suggests that Lo`ihi’s long term eruptive behavior may provide insight into future activity at Kilauea.

The 1996 Lo`ihi earthquake swarm was preceded by over a decade of seismic activity. From 1986 to 1996, the seamount experienced several earthquakes per month, as well as near annual earthquake swarms. Although Lo`ihi’s location below sea level makes it difficult to determine when it was erupting, there is evidence of eruptive activity in 1990 and in early 1996, well before the earthquake swarm. The 1996 event began with increased seismic activity within Lo`ihi’s south rift zone, after which seismicity moved to the summit area. This parallels Kilauea’s behavior in April and May of 2018. In both cases summit activity was highly energetic: Lo`ihi experienced over 100 M4+ earthquakes during the event, and Kilauea’s activity included >50 M5+ events. Perhaps most striking, both summit swarms were associated with the collapse of a significant portion of the summit, creating Pele’s Pit on Lo`ihi and massively enlarging the Halema`uma`u crater on Kilauea. Relocations of Lo`ihi earthquakes confirm a tightly concentrated zone of summit activity that is likely associated with pit crater collapse.

Following the 1996 event, seismicity at Lo`ihi tapered dramatically, and it remained low until 2015. This period included two deployments of instruments directly on the volcano, confirming that the quiescence was real. Seismicity gradually increased, and near-annual swarms initiated again in 2015. If these similarities in behavior between these volcanoes are a guide to the future, we speculate that it may be as much as two decades before Kilauea becomes active again.

Presenting Author: Jacqueline Caplan-Auerbach

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