Nov 28 1995, 3:00 pm - Ruapehu Volcano

Situation Summary

As of 15:00, the situation at Ruapehu is:

• Today the volcanic tremor has remained at a similar level to that observed for the last few days, with the mean seismic ground velocity about 3 - 4 μm/s. High frequency volcano-tectonic earthquakes continued to register on The Dome seismograph at the rate of 10 - 12 per day.

• Earlier today the weather conditions allowed visual observations, and some field work has been undertaken. As with most clear days recently, the gas plume was visible this morning. Fresh snow has fallen obscuring any evidence of possible eruptive activity over the weekend. An attempt is being made this afternoon to make an overflight and obtain COSPEC data.

  Days since last major ash fall* on 14 October 1995	45
  SGV** at Dome: mean for 24 hours to 4:00 pm on 25 November 1995	~3 - 4 μm/s
  Days since SGV** last ≥10 μm/s on 27 October 1995	32
  SO2 flux: last measured on 23 November 1995	963 t/day
  Deformation as of 17 November 1995***	steady state
  * 1 mm thickness at 5 km radius ** Seismic ground velocity *** EDM at Whakapapa, Turoa and Tukino

Conclusion and Alert Status

At present the level of volcanic activity is low, however we advise the Alert Level remains at 3.

B.J. Scott (for C.J.N. Wilson)
Volcanology Programme Leader