Saturday, January 22, 2011

The Power of Volcanoes

National Museum held an very interesting and information talk on The Power of Volcanoes in conjunction with their Pompeii exhibit. Pompeii is a Roman town which was buried in volcanic ashes in 79 CE.

Instead of the usual 1 speaker, we had 2 volcanologists addressing the audience. Dr Chris Newhall from Earth Observatory, S'pore started by highlighting how a volcanic eruption in one country could have international impact due to the inter-connectivity of global aviation. We listened to a taped conversation between the pilots of a commercial plane and the airport control tower when the plane was caught in volcanic 'cloud'. We could hear the stress voice of the pilots when the plane's engine stalled. The speaker then related this back to the Icelandic Mount Eyjafjallajoekull’s eruption in April 2010, which caused the greatest disruption in air travel in major parts of Europe and the UK since the second World War.

Dr Antonius Ratdomopurbo, Volcano Seismologist who has spent more than 2 decades studying volcanic activities in Indonesia showed pictures and video clips on the deadly eruption of Indonesia’s Mount Merapi in 2006 and 2010. We learn that volcanoes 'explosive' forces is also classify just like earthquake magnitude. It range from 1 to 8, the higher the number, the more powerful the eruption forces. Each increase in number reflects a multiple of 10 times more the damaging force. The number give an indication of the volume of volcanic lava/ashes and also how wide spread will be the damage.

We were told that though Mount Merapi eruption is consider minor (classify as 3 and 4 in 2006 and 2010 respectively), the damage done by the lava and volcanic ashes which can spread far and wide is severe. Mount Merapi which is in Central Java erupts frequently every few years.

Mount Pinatubo in Luzon, Philippines, eruption in 1991 was considered the second largest eruption of the 20th century. It last eruption was more than 400 years ago. Normally the more powerful the volcanic eruption, the longer the time interval between next eruption. Mount Pinatubo volcanic cloud spread a radius of more than 500km !

We learned that even low tech observation and measurement method could still give an accurate prediction on the likelihood of a volcano erupting. For example, the diameter of the crater increases and the physical contour of the crater changes in shape. The difficulty is in predicting exactly when it will erupt and the severity of damage which affects the area of evacuation.

Prof Tommy Koh was in the audience and he asked the speakers if S'pore could be affected by Indonesian volcanic activities. The answer is yes, if the volcano nearest to S'pore erupts and the wind direction is blowing in our direction. S'pore could be affected by the volcanic ashes up to a few cm thick.

The audience also raised the question of the impact of volcanic activities on proposed nuclear plants to be built in Asean region. Though there is way to protect the plant from volcanic ashes but it is still a danger to have such plant sited in volcanic belt and earth quake zone. Seems like in the past, there has been no guideline on this matter. Hopefully more stringent standard would apply to suitability of nuclear facility location.

No comments: