Mount Tongariro eruption takes New Zealanders by surprise: volcanic lesson will be repeated many more times in the future

August 7, 2012 – NEW ZEALAND – Ash from New Zealand’s Mount Tongariro covers houses and farmland in this still image taken from video, August 7. A New Zealand volcano dormant for more than a century has spewed boulders and spread an ash cloud over the center of the country, disrupting air traffic but causing no other damage or injuries. A volcano quiet for more than a century erupted in a New Zealand national park, spreading thick ash for several miles and causing some residents to evacuate their homes. Some domestic flights were canceled Tuesday. Mount Tongariro spewed ash and rocks for about 30 minutes late Monday night after a few weeks of increased seismic activity. It didn’t cause any injuries or damage in the sparsely populated central North Island region. Tongariro National Park has three active volcanos, is a popular tourist destination and was the backdrop for many scenes in the ‘Lord of the Rings’ movies. Some residents left their homes as a precaution, and authorities temporarily closed roads. National carrier Air New Zealand canceled or delayed domestic flights to towns near the mountain, though by Tuesday afternoon, it said it was resuming service to locations where the ash cloud had cleared. No international flights were affected. Police said a witness to the eruption described flashes and explosions followed by a cloud of ash coming from a hole in the north face of the mountain. The Department of Conservation said three hikers were staying in a hut on the opposite slope of Mount Tongariro when it erupted but they walked out of the area safely. Steve Sherburn, a volcanologist at the government agency GNS Science, said the eruption spread a layer of ash one or two inches thick for several miles. He said he’d heard reports of ash traveling on wind currents to coastal towns 60 miles away. He said the eruption was likely caused by steam pressure building within the mountain. The nation’s civil defense ministry said eruption activity was subsiding though it still urged caution for people who were in the vicinity of the volcano. The park has closed hiking trails and sleeping huts on the mountain for now. –CSM

Caught by suprise: GNS Science volcanologist Michael Rosenberg said volcanic activity could continue for weeks. “This eruption caught us by surprise. We’ve been monitoring the area after earthquakes, but we didn’t expect this,” he told TVNZ. –Discovery News

Unpredictable menace: Monday’s Tongariro eruption could be the start of a multitude of larger eruptions, spewing even more ash into the air, a disasters and hazards expert says. Dr. Thomas Wilson, lecturer in hazards and disaster management at Canterbury University, says activity on the mountain could change quickly. However, it is difficult to know what will happen next and although things could get worse the volcano might settle down completely or small eruptions could continue. “I can’t give you any probabilities on the likelihood of these scenarios,” he said. “But we can’t rule anything out at this stage.” The volcano erupted at 11.50pm, spewing ash from the Te Maari craters on the northern side of the mountain. It has disrupted flights over the central North Island, and aerial news footage shows a fine covering of ash downwind from the volcano. What happened in southern Japan following the eruption of the Shinmoedake volcano in 2011 is similar to what would happen in New Zealand if a much larger eruption was to occur at Tongariro, Dr Wilson says. Centimetres of ash covered farms and towns, impacting on agriculture but it took just six months for things to return to normal.  –3 News