boats have as yet been in the neighborhood of the volcano." There were many other news reports on the eruption, one describing the eruption as "a terrific earthquake which burst the mountain asunder leaving a large gap," which could possibly suggest the crack formation in the volcano's crater, however, it is unlikely. Supposedly, the volcano was ejecting "flames" from its crater, and the eruption terrified natives in the area. Newspapers seemed to suggest that the ash had traveled for more than , reaching the opposite side of the Cook Inlet. 1989–1990 The volcano erupted on December 14, 1989, and continued to erupt for over six months. Sudden melting of snow and ice at the summit caused by pyroclastic flows and dome collapses caused lahars, or mudflows, which flowed down the north flank of the mountain. A majority of the mudflows coursed to Cook Inlet, about from the volcano. The lahars entered a nearby river, worrying officials that they might destroy an oil storage facility located along it. Since lahars were produced repeatedly, scientists realized that they could use these to analyze a trial period for a newly developed device proposed to measure the movement of rocks against each other. This device, now known as an Acoustic Flow Monitor, alerts nearby stations to possible lahars. The eruption also caused an airliner to have all four engines fail after a Boeing 747-400 jumbo jet operated by KLM Royal Dutch Airlines flew into a cloud of volcanic ash. Damage from the eruption was estimated at $160 million, the second costliest volcanic eruption in United States history. 2009 Pre-eruption On January 24, 2009, a magnitude 5.8 earthquake hit the region at a depth of 98 kilometers. The relation to the eruption is unknown, but was the strongest in the vicinity since 2001. On January 30, 2009, scientists from the Alaska Volcano Observatory (AVO) warned that an eruption was imminent, sending experienced Alaskans shopping for protection against a dusty shower of volcanic ash that could descend on south-central Alaska. 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 fly over conducted by the AVO detected "significant steaming from a new melt depression at the mouth of