The 1991 eruption of Mount Pinatubo was one of the largest volcanic eruptions of the 20th century. Explosive activity began in early April as a series of well explosions from a crack that opened on the north side of Mount Pinatubo.
On June 12, the first spectacular eruption of the volcano sent a column of ash about 20 kilometers into the atmosphere. Additional explosions occurred overnight and on the morning of 13 June. Seismic activity during this period continued reaching the ash cloud at 40 kilometers.
Several lowland towns were flooded or partially buried in mud. More than 800 people were killed from the collapse of roofs under wet heavy ash and several more were injured.