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The Biggie!

The Pinatubo eruption of 1991 was one of the largest eruptions the world had seen for some 100 years.

An Imminent Eruption

Mount Pinatubo is located on the northern Island of Luzon in the Philippines. It is an active stratovolcano in the Zambales Mountains, NW of Manila.

In 1991 the volcano started to show signs of unrest around March and April time. Given all the signs that a very large eruption was imminent, the Philippine Institute of Volcanology and Seismology – assisted by the United States Geological Survey (USGS) – worked to convince local inhabitants of the high severity of the threat, and started evacuating people.

Image Credit: USGS

Eruption

On the 12-15th June 1991 the Volcano suffered major explosive eruptions that reduced the mountain’s height from 1,745 m (5,725 ft) to 1,485 m (4,872 ft), the eruption was 10 times that of the 1980 Mount St Helens one.

Image credits: USGS, Alberto Garcia

Ash in the Atmosphere

The volcano was being monitored by volcanologists including a team from the USGS who were working out of the US Clark Air Base, near the volcano. Satellites were also able to collect valuable information about how the ash and gases from the volcano were affecting the atmosphere.

video credit: USGS. for more information check out NASA Earth System Data Explorer

Pinatubo and short term climate change

Tanno and Iguda have found out that the monitoring of the atmosphere after the eruption showed that it lowered the global average temperatures by 0.5–0.6 °C.

Look at these false colour images of aerosol optical depth in the stratosphere, over a period from April 1991 to January 1994. Red colours show the highest values with dark blue showing the lowest. The Pinatubo/Hudson eruptions increased aerosol optical depth in the stratosphere by a factor of 10 to 100 times normal levels. (‘Aerosol optical depth’ is a measure of the prevention of light passing through a column of the atmosphere by the presence of airborne particles) (NASA).

Image Credit: USGS

This was one BIG eruption!!

You can see by these before and after shots taken by the USGS team, just how much of the mountain was blown away.

Pinatubo before Pinatubo after

After the volcano…

All the loose rock and ash is a major hazard after eruptions. Particularly in tropical areas where it rains a lot. It can get reworked into large mudflows, called ‘lahars’, which travel fast down valleys taking out bridges and buildings.

Image credit – USGS

Combined Effects

Tanno and Iguda have discovered that the volcano Mount Hudson in Chile erupted explosively close to the time of the Pinatubo eruption. It is thought that the combined effects of these two big eruptions helped to contribute to the short term climate changes that we saw from the NASA data.

Image credit – USGS

Ash plume image from August 1991 of the Mount Hudson eruption. Image Credit: NASA

YOUR MISSION, SHOULD YOU CHOOSE TO ACCEPT IT …

YOUR MISSION, SHOULD YOU CHOOSE TO ACCEPT IT …

YOUR MISSION, SHOULD YOU CHOOSE TO ACCEPT IT …

YOUR MISSION, SHOULD YOU CHOOSE TO ACCEPT IT …

Make a science poster about volcanic hazards!!

Using your knowledge gained from the Pinatubo and Mount St Helens, make up a poster that covers aspects of volcano hazards.

Your Task

  • You can design your poster on the computer or simply by using a set of pages stuck onto a larger page or piece of card.
  • One cool and easy way is to mix computer printed out pages (e.g. pictures and text) with your own pages. You can also link between pictures and pages with coloured string.
  • Remember to make your poster clear and simple enough for people to follow… what’s the title of yours going to be?

You can make your poster as colourful and interactive as you want – maybe, you could put flaps on it that reveal facts.

Science posters are often presented at conferences to show some research and topics that scientists have been working on.

– MISSION END –

– MISSION END –

– MISSION END –

– MISSION END –

Your Journey So Far …

Tanno and Iguda have explored these places up to now. You can go back and visit again by clicking below.

Stromboli

Vesuvius

Erta Ale

Iceland

Villarica

Mt Erebus

Mt St Helens

Sarychev

Mt Fuji

Pinatubo

Great to see you here, thank you for the visit! See you next time …

Tanno & Iguda