Volcanoes quiet

Ruapehu Bulletin, Volume 12, Issue 558, 18 October 1994, Page 8

Volcanoes quiet

Volcanic eruptions have dominated the headlines during the last month, however none of the eruptions were in New Zealand. Several of the Institute of Geological and Nuclear Sciences staff at Wairakei are keenly following the Rabaul eruptions as they have worked and lived there. Although the Rabaul eruptions have been small, a lot of volcanic ash has been erupted. The scientists from NASA have produced some data from their satellites which show that more than 1 .5 million squarekilometres down wind of the eruptions were showered

with ash, reaching right across Papua New Guinea and almost to the northern tip of Australia (Cape York). Sleep in New Zealand New Zealand' s volcanoes continue to sleep. Crater Lake at Mount Ruapehu continues to cool slowly and is now down to 14 degrees Celsius. The crater lake temperatures at Raoul Island are starting to rise but this is normal for these lakes as the climate has a significant effect on their temperatures.

White Island was visited on 5 October and no further activity has occurred. Earthquakes have continued - our autolocation system has located 34 in the last month. The greatest concentration was in the Okataina volcanic centre. All were small, less than magnitude 3.6 on the Richter scale. The behaviour of Inferno Crater lake at Waimangu has changed again. This crater lake occupies a crater formed in 1886 when Mount Tarawera erupted. Presently the lake level is rising and falling about 2m and overflowing every 3-5 days. Usually the water level rises and falls 8m, overflowing every 38 days. This type of activity has occurred before. Lottery grant The only big news on the local earthquake front this month is that IGNS has recei ved a $35 ,000 grant from the Lottery Board to establish three seismometers about Taupo Volcano. They hope ultimately to have fi ve and say this is a good start. The above is a summary of volcanic, earthquake and geothermal activity in the Taupo Volcanic Zone. This summary is based on studies and observations by staff at the Wairakei Research Centre, Institute of Geological & Nuclear Sciences Ltd, observations by tour operators, Department of Conservation staff and the general public - it covers the period from early September to early October 1994: