 By January 31 , volcanic earthquakes increased to several per hour , and a large hole in the glacier on the side of the mountain was spotted . Scientists began to monitor seismic data from the mountain twenty @-@ four hours a day in an effort to warn people in nearby communities . A flyover conducted by the AVO detected " significant steaming from a new melt depression at the mouth of the summit crater near the vent area of the 1989 @-@ 90 eruption . " 
