Description of eruption There was a small eruption before the sun came up on April 5.The next day there was an ash plum with a diameter of 50 kilometers.This eruption caused about 25 cm of ash to fall on the slopes of the volcano.On April 8th and 9th a second explosion occurred and this one also had an earthquake. Hot mud flows flowed down the mountain at around 60 km an hour. A series of eruptions occurred in the next months. During the eruption ash shot up as high as 16.5 kilometers. The ash caused one planes engines to stop running but after falling 25,000 feet the engines were able to restart. The eruption caused the lava dome from 1918 to be replaced by a new crater 800 metered wide.