The 4 May 2018 Mw 6.9 Hawaii Island Earthquake and Implications for Tsunami Hazards

The 4 May 2018 (Mw 6.9) earthquake offshore of Kilauea Volcano has raised concerns about potential impacts of locally generated tsunamis in Hawaii. Iterative inversion of global seismic observations guided by forward modeling of regional geodetic and tsunami records yields a self‐consistent fault slip model to quantify the physical processes. This earthquake, similar to other large events in the area, is found to involve a shallowly dipping thrust fault, plausibly on the décollement between the island volcanic edifice and the old Pacific seafloor. The uplift and seaward displacement of Kilauea's south flank generate a tsunami that wraps around Hawaii Island, exposing all shores to direct arrivals and the interconnected insular shelves to resonating wave activities. The impact along the Hawaiian Islands can be categorized at three regional levels in terms of peak wave amplitude and arrival time with implications for tsunami hazards from future larger earthquakes and flank failures.