Eruption 21 November 2012
21 November 2012 Eruption
Tongariro eruption time series.pdf (1.45 MB)
After reviewing monitoring data, videos and images for the 21 November 2012 eruption at Tongariro, GNS Science confirms that the eruption lasted approx 5 min, with an ash column and plume being ejected 3-4 km above the Upper Te Maari crater.
The eruption was recorded by GeoNet’s webcam. Watch a video of the eruption.
The point of origin of the 21 November 2012 eruption was similar to that from the eruption August 6, 2012. During the recent eruption, two small pyroclastic density currents were produced at the base of the column, to the West and North of the crater, and reached a limited distance of a few hundred meters downslope. These pyroclastic density currents are a mixture of ash, volcanic gas and atmospheric air flowing horizontally and being driven by gravity. Scientists believe that these were produced by part of the ash column not being energetic enough to rise, causing it to collapsing at the base and flow downhill. There is no evidence at this stage of big blocks having been ejected far from the crater during the eruption.
From the preliminary examination of ash, GNS Science volcanologist Michael Rosenberg reported that “we haven't found any evidence yet of magma having reached the surface during the eruption”. More ash sampling and analyses by New Zealand volcanologists are planned or already underway.
There was no observed warning immeditately prior to yesterday’s eruption. Future eruptions could also occur with little or no warning.