Description: From McGimsey and Wallace (1999): "On May 19, 1997, seismicity at Iliamna abruptly and dramatically increased. Analysis by AVO seismologists suggested that the activity probably resulted from a local avalanche or rockslide. A large avalanche of mixed snow, rock, and ice cascaded down the east flank on June 30, 1994, producing a similar seismic signature (Neal and others, 1995). An AVO field crew dispatched to make observations verified that indeed a large avalanche, composed mostly of ice and snow with some rock debris, had originated at the 7,500-foot (~2,300-meter) level and had cascaded down the east flank, mimicking the 1994 avalanche." This activity does not constitute a volcanic eruption.