Breaking Volcanic News: New Zealand
March 21, 2007
Photo: Since last May Mt Ngauruhoe has had 20-30 earthquakes a day. Photo / Mark Mitchell
Now it's Ngauruhoe Volcano rumbling into life - Mt Ngauruhoe, Mt Ruapehu's volcanic neighbour, is getting restless. The two mountains are believed to share the same magma source beneath the Earth's crust. Mt Ngauruhoe has shown "significant" increases in earthquakes over the past eight months, stirring after more than 30 years of deep sleep. Ngauruhoe had been shaking about twice daily between 1975 and May last year. However, since then it has regularly had between 20 and 30 earthquakes a day, peaking at more than 50 shakes within 24 hours. The unrest at both mountains relates to a special low-frequency type of earthquake, which is often linked to the underground movement of gas, hot water or magma. Before Sunday's lahar, between four and 60 small earthquakes were recorded daily at Mt Ruapehu's Crater Lake. But in the 24 hours following the lahar about 100 earthquakes were detected. The increased unrest had almost certainly been caused by the crater lake emptying out 1.29 million cubic metres of water, causing its level to drop 6m. "There's a hint they've tapered off now but because things are so variable we need to watch this over the course of a week."
ECUADOR - As the Tungurahua volcano returns to slumber after erupting earlier this month, it is still urgent to maintain a sufficient number of shelters in good condition to provide for the population should the volcano resume activity – which could at any time be as extreme as it was last summer when the volcano erupted in August. Ash from the volcano has affected people in the region who depend on agriculture as their sole source of income. Road passage is also an unpredictable danger right now, while everything is covered in ash, since rain may move the ash deposits and cause landslides and avalanches.