Mount Pinatubo, Philippines Zoe Rose

Causes of the volcanic eruption On July 16, 1990, a magnitude 7.8 earthquake (comparable in size to the great 1906 San Francisco earthquake) struck about 100 kilometres northeast of Mount Pinatubo on the island of Luzon in the Philippines. At Mount Pinatubo, this earthquake caused a landslide and there was an increase in steam emissions from a pre- existing geothermal area, but otherwise the volcano seemed to be continuing its 500-year-old period of inactivity. In March and April 1991, however, some magma started rising toward the surface from more than 30 kilometres beneath Pinatubo which triggered small earthquakes and on 2 April 1991 this caused powerful steam explosions that blasted three craters on the north flank of the volcano. Thousands of small earthquakes occurred beneath Pinatubo through April, May, and early June, and many thousand tons of sulphur dioxide gas was also emitted by the volcano.

From June 7 to 12, the first magma reached the surface of Mount Pinatubo. Since it had lost most of the gas contained in it on the way to the surface, the magma oozed out to form a lava dome but did not cause an explosive eruption. But then huge amounts of gas- charged magma reached the surface and exploded in a spectacular eruption. When even more highly gas charged magma reached Pinatubo's surface on June 15, the volcano exploded and that ejected more than 5 cubic kilometres of material. The ash cloud from this eruption rose nearly 40 kilometres into the air. At lower altitudes, the ash was blown in all directions by the intense cyclonic winds.

Consequences

Social effect 847 People Killed from collapsing roofs, 100 from the mud flows known as lahars, the rest from diseases in the evacuation centers. 650,000 workers lost jobs $700 Million Damages 1.2million people lost homes and had to migrate to shanty towns in another city. Electricity went off, water was contaminated, road links were destroyed, and telephone links were cut

Environment effect The ash in the atmosphere caused global cooling by 0.5°C Fast flowing volcanic mudflows (lahars) caused sever river bank erosion, undercut bridges etc Volcanic ash was blown in all directions over hundreds of Kilometers, smothering fields and buildings.

Economic effects Farmland destroyed by falling ash and pumice, unusable for years, the 1991 harvest was destroyed and 650,000 people lost their jobs $700 Million Damages Heavy rainfall caused buildings to collapse. Houses and bridges destroyed needed replacing and Manila airport had to be closed.

Management predictionpreventionpreparation 75,000 people were evacuated due to accurate predictions. There was no monitoring until the 3rd of April but seismometers were put into place. USA air force helicopters helped evacuate people. Warning sign like gas and steam looked for. Long and short term aid organized especially from the Red Cross and the United States. Alert systems were put into place to warn people of eruption. Evacuation camps were built for refugees. Government Shelters

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