when was the last time mount ruapehu erupted
25 September 2007
title: Mount Ruapehu text: between major eruptions. Ruapehu is largely composed of andesite and began erupting at least 250,000 years ago. In recorded history, major eruptions have been about 50 years apart, in 1895, 1945 and 1995–1996. Minor eruptions are frequent, with at least 60 since 1945. Some of the minor eruptions in the 1970s generated small ash falls and lahars (mudflows) that damaged skifields. Between major eruptions, warm acidic Crater Lake forms, fed by melting snow. Major eruptions may completely expel the lake water. Where a major eruption has deposited a tephra dam across the lake's outlet, the dam may collapse after the title: Mount Ruapehu text: increased chemical changes, gases and temperature. The warning was used to let visitors know the potential of an explosion was higher than usual and could happen at any time. This could also be a follow-up to the previous year's 2007 eruption. A GeoNet New Zealand Bulletin was released on 21 July 2008 stating that "the current phase of volcano unrest appears to be over, however Ruapehu remains an active volcano. Future eruptions may occur without warning." However the level has remained at 1, where it has been since 1997. On 5 April 2011 Geonet changed Mount Ruapehu's Volcanic Aviation Colour title: Mount Ruapehu text: small eruptions that spread thin layers of ash across both Whakapapa and Turoa ski areas, the ski fields opened for the 1996 season. Turoa closed on 29 September – earlier than usual, while Whakapapa stayed open until Labour Weekend. After the 1996 eruption it was recognised that a catastrophic lahar could again occur when Crater Lake bursts the volcanic ash dam blocking the lake outlet. This is the same mechanism that caused the 1953 lahar. The lake gradually filled with snowmelt and had reached the level of the hard rock rim by January 2005. The lahar finally occurred on 18 title: Mount Ruapehu text: March 2007 (see below). Ruapehu erupted at 10.30pm on 4 October 2006. The small eruption created a volcanic earthquake at a magnitude of 2.8, sending a water plume 200 m into the air and tall waves crashing into the wall of the crater. On 18 March 2007, the tephra dam which had been holding back Crater Lake burst, sending a lahar down the mountain. An estimated 1.4 million cubic metres of mud, rock, and water travelled down the Whangaehu river. The Department of Conservation had received warning signals from the lahar warning system (ERLAWS) at around 10:30 that morning and title: Mount Ruapehu text: corrosion on the turbine blades which had to be rebuilt. Episodic eruptions continued until the end of November 1995. Within hours of a major eruption during the night being reported on 25 September 1995, news media were trying to get live video of the eruption and amateur photographers had published eruption images on the World Wide Web. A web camera, dubbed the world's first "Volcano Cam", was set up. Since then Ruapehu has been monitored by at least one and sometimes several volcano cams. Another, smaller, eruption phase began on the morning of 17 June 1996. Despite a series of