Volcano Watch: The missing slow slip events on Kilauea’s south flank

USGS graphic The top panel is from before the 2018 Kīlauea eruption and shows two steps corresponding to slow slip events (SSEs). The bottom panel is from after 2018 and shows no evidence of step-like motion indicative of SSEs, although the slight curve does suggest that a post-eruption increase in seaward motion is slowly returning to background. The inset photo is of the KAEP instrument site, on Kīlauea’s south flank.

Over the past two decades, both scientists and members of the public have anticipated the occurrence of slow slip events (SSEs) on Kilauea’s south flank. These events are recorded by the Hawaiian Volcano Observatory’s continuous GPS network, which show as much as 2 cm (0.75 inches) of increased seaward motion of the flank over 2-3 days — equivalent to about an M6 earthquake.