Discovery

The Big Smoke Becomes Reality

By Robert Turnbull is in the fourth form at Kelston Boys High School in Auckland.

The threatening purple and dirty orange clouds interspersed with bright bolts of fire have finally cleared, leaving a dull grey sky. Seven metres of ash, mud, pumice rocks and lava has been deposited over an area from the Firth of Thames to Warkworth.

Latest pictures from the Sojourner and Mars? War of the Worlds perhaps? Unfortunately not! This is the aftermath of a volcanic eruption occurring somewhere in greater Auckland. Many Aucklanders do not consider the volcanoes in their own back yard to be a real threat and, as a result of this, they are unprepared for a volcanic episode.

Many of Auckland's 49 known volcanoes are extinct, while some, notably Rangitoto, are only dormant. There is a possibility that these dormant volcanoes once again could spew forth their fury. However the stronger, more frightening, probability is that an eruption will occur in a new location. Unlike New Zealand's most recent eruption at Ruapehu in the midst of a relatively unpopulated National Park, any eruption in Auckland must have a greater impact because of the population density.

David Scott, a local resident at Ohakune during the 1995/96 eruption of Ruapehu, says that it was the uncertainty and "not knowing what the volcano was going to do next" which was the most frightening. The actual eruptions, especially at night with the hot molten rock being thrown up into the sky, were "quite a spectacle". The eruption caused an absolute standstill for business in the area which made a huge impact on people's lives and, even a year later, things have not picked up to pre-eruption levels. Ohakune suffered from only three ash dumpings, most fallout going northeast towards the Bay of Plenty. The effect on Auckland would be a thousand times greater simply because such a vast population would be in closer proximity to any eruption.

Scientific research seems to favour the theory that an eruption occurring in Auckland will be what is known as an "explosive" type. Pressure builds in a subterranean magma chamber partly due to the Earth's gravitational force field. Magma is forced upwards and comes in contact with subterranean water. The combination produces a phreatic explosion catapulting volcanic and crustal material into the air.

If an eruption did occur in Auckland what would it look like? Possibly like Kilauea in Hawaii, which is a basalt volcano, the least destructive and comparatively tame. It could be a sulfurous red hot cauldron producing a Rangitoto-shaped cone and fiery fountains of lava hundreds of metres into the sky. Or it could blast from the ground like a nuclear bomb as happened long ago at Three Kings, Auckland's largest explosive volcano.

Scientists use local seismographs to take readings closer to the action to provide more detail. People on different emergency committees would come from all over New Zealand to study and help if there was a likelihood of a volcanic eruption.

The Auckland Regional seismologist will be the first person to be aware that all is not right. If he/she feels something is wrong, the local members of the emergency committee will be contacted and a meeting will be held.

If there was a continuation of tremors of reasonable amplitude and frequency, a volcanic eruption would be taken into consideration. In New Zealand there is a five-stage alert system and the volcanic tremors would be a Stage Two alert -- they have confirmed that the abnormal is true.

Civil Defence would also play a major part in this operation. At Stage Two, the head of Civil Defence for the Auckland region, David Keay, says he would still require more information but he would contact local police commanders and possibly have a quick meeting with the emergency services. At this stage the first radio broadcasts would be made and that would be followed by a deluge of calls from worried citizens -- but some calls could provide useful information in pinpointing the location of the possible vent. Stage Three is when the volcano is leading seriously towards an eruption episode. The emergency services would step up a gear. By this stage an eruption site can be accurately pinpointed by the tremors and earthquake clusters.

Although an eruption is imminent, Civil Defence themselves admit that people are reluctant to abandon their homes and businesses without the visual evidence of an open steaming vent. This would add to Civil Defence's difficulty of an orderly evacuation as in these circumstances a full-scale eruption is only a matter of hours away.

The effects on urban Auckland would be devastating. It would grind the city to an absolute standstill and block sewage and storm water drains which would lead to flooding and make roads impossible to travel on.

In the end the question remains -- not if, but when? Scientific research would seem to indicate that the Auckland volcanic field is "hotting up", part of a worldwide trend which has seen more frequent and violent spells of volcanic activity.

More than 50,000 years ago there were approximately ten volcanoes in the Auckland field; 50,000 to 20,000 years ago another 27 came to life; in the last 20,000 years approximately another nine plus Rangitoto (the latest) which spewed out more ash and rock than the previous ones altogether. Rangitoto last erupted 600 years ago and analysing scientific data would suggest Auckland is well and truly due for another volcanic episode!

Just as Easy as

By Emily Hodgkinson

There are drug patches available on the market today; for smokers who want to quit there are nicotine patches, for example. However, most of the thousands of drug molecules in existence are too big or too water soluble to easily slip through the skin. They are stopped by the paper-thin outside layer of the skin which consists of dead skin cells glued together by a fatty molecular substance. This layer bars all but the smallest and oiliest of molecules from entering the body. This is why designers are devising schemes such as using sound and electricity to push the bigger chemicals through the skin.

Repelling Dogs

By Alice Doig

This year 53 Salvation Army collectors were bitten severely by dogs. Dog bites were the most common cause of absence from work at NZ Post. Two thousand ACC claims were because of dog attacks. So what can be done about it?

Andrew Rakich might have the answer. He has developed an unusual way of fending off dogs with a synthetic skunk spray...

Chemists at Victoria Link have worked out ways of synthesising the three most potent chemicals and mixed up a cocktail dissolved in alcohol which they then put into a high-discharge aerosol can.

See also Viewpoint

Alice Doig is a pupil at Aotea College
Emily Hodgkinson is a pupil at Wanganui High School
Robert Turnbull is in the fourth form at Kelston Boys High School in Auckland