An unusual pattern of recurring seismic quiescence at Kalapana, Hawaii

An unusual pattern of recurring seismic quiescence is observed in the Kalapana, Hawaii region of Kilauea Volcano. Statistically significant intervals of quiescence preceded the Kalapana earthquakes of 1975 (M7.2) and 1989 (M6.1) and a third quiescence is presently underway. The sensitivity of the volcano flank to continuing magmatic activity in the nearby east rift zone complicates interpretation of these observations. The current quiescence episode may be caused by magmatic processes in the east rift zone or by changes within the flank of Kilauea. The latter possibility, if correct, may represent a precursor to another earthquake.