Mount Pinatubo Eruption

Mount Pinatubo in 1991.  Courtesy Wikipedia Commons

Having climbed up Mount Pinatubo last Sunday, I thought it might be useful to do a little research on the eruption which took place in June 1991 and put this "forgotten" volcano back on the map. Ironically, we were in Manila a little while after the Pinatubo blast and got stuck here for four days.  All flights were cancelled because of the volcanic ash raining down everywhere.

 As I understand it, Mount Pinatubo lay dormant for about 450-500 years.  It was not generally known to be an "active" volcano. It was not in any way noticeable like other famous Philippine volcanoes such as Mount Mayon (near Legazpi in the Bicol region) which is picture perfect and what every kid would immediately recognize as a volcano.  

Mount Pinatubo Smoke Plume, 1991.  Courtesy USGS.

Pinatubo was a shy volcano--a real sleeper.  Interestingly, the indigenous Aeta people who live on and around Pinatubo had folk memories of a huge explosion many moons ago--except that it was caused by a giant turtle that the hunters had chased up the mountain.  Trapped at the top of the mountain, the giant turtle began digging down into the mountain and then sent out a lot of fire and rocks to drive the hunters away!

After a series of earthquakes which began  in June 1990, Mount Pinatubo finally erupted on June 15, 1991.  The eruption went on  for nine hours and the top of the mountain actually collapsed, thereby causing further earthquakes and the caldera we see today.  The collapse reduced the summit by about 800 feet!


The various earthquakes of the preceding year had alerted vulcanologists and the authorities to the danger and a series of evacuations were undertaken before the ultimate blast.  The evacuations literally saved tens of thousands of lives.  I was told that only about six people were killed by the eruption itself.  The real problems came when Typhoon Yunya passed close to the volcano during or almost immediately after the eruption.  What are the odds of being hit by a volcanic eruption and a typhoon at the same time?

The massive rainfall combined with ash and volcanic debris brought down landslides and walls of lahar, that grey, cement-like deposit that we drove through and over last Sunday and which, ultimately, covered huge areas of this region of Luzon.  Houses collapsing under the weight of ash and torrents of lahar caused up to 800 deaths. Whole towns and villages were wiped out or severely damaged, including the town of Capas where we picked up our 4-wheel drive vehicles.  One year later, further waves of lahar killed many more people and heavy rainfalls continue to pose a danger of lahar action.

Mt. Pinatubo before eruption.  Courtesy Wikimedia Commons

Quite apart from the physical damage, millions of tons of sulphur dioxide were spewed into the atmosphere and caused reduced temperatures around the world for a number of years after the eruption.  In fact, Pinatubo had the largest impact on the stratosphere since Krakatoa in Java, Indonesia, blew its top in the late nineteenth century.  The plume from Pinatubo reached 21 miles high and was spread over 250 square miles. Of course, it was spread world wide as time went on and was responsible for some of those magnificent sunsets we saw     back then.

It also led to the forced evacuation of the US Clark Air Base which has now been returned to the Philippines.  It is very sad to see the damage that Mount Pinatubo has done to the agriculture in the surrounding area and to the various river systems that became clogged with lahar.  This region of Luzon was once called the "rice basket" of the Philippines.  It has a moon-like quality to it now and many people have been forced off the land.

We can only hope and pray that Mont Pinatubo goes back to sleep for another 500 years--or even longer.  It looked very peaceful and beautiful last Sunday; but its vast power and destructiveness have left terrible scars across this beautiful part of the country.

If you want to see some more photos of the eruption, have a look at:

http://www.livescience.com/14476-photos-mount-pinatubo-largest-volcanic-eruption.html