The Rupture Process of the 2018 M_w 6.9 Hawaiʻi Earthquake as Imaged by a Genetic Algorithm-Based Back-Projection Technique

An episode of unrest began at Kīlauea in April 2018 that produced both significant volcanic output and high rates of seismicity, including a M_w 6.9 earthquake on 4 May 2018. In this study, we image the rupture process of this earthquake using a genetic algorithm-based back-projection technique. The dominant feature of the earthquake is a slowly propagating western rupture, which shares similar characteristics with the region's largest recorded event in 1975 (M_w 7.7). The location of this western segment suggests that small asperities on this section of the décollement that frequently fail as slow slip events may achieve seismic slip rates when rupture is initiated on adjacent sections of the fault. Given the interaction between volcanic and seismic activity in this region, imaging the rupture properties of these events can improve our understanding of future geologic hazards in this region.