Lightning Associated with the August 18 , 1992 , Eruption of Crater Peak Vent , Mount Spurr Volcano , Alaska

The Alaska Volcano Observatory's lightning detection system detected and located 171 lightning strokes during the August 18, 1992, eruption of the Crater Peak vent of Mount Spurr volcano in Alaska. The strokes, predominantly intracloud, were detected during a 70-minute interval that began more than an hour into the eruption. All detected strokes were of positive polarity. The spatial distribution of the strokes in the horizontal plane defines a ring-like pattern approximately 10 km in diameter and displaced roughly 5 km to the east of Crater Peak. Although lightning was observed during the September 16-17, 1992, eruption of Crater Peak, no lightning was detected by the lightning detection system.