Ruapehu - IGNS - Science Alert Bulletin V95/53

Monday 23 October 1995
1600 hours NZDT (UT +13)
Ruapehu Volcanic Activity

Situation Summary

As of 1600 hours, the following information is available.

*     Seismic activity has been relatively low during the last 24 hours,
with low levels of  background volcanic tremor recorded on the Chateau and
Dome (summit) instruments. Numerous degassing eruption type events (bursts
of increased tremor without sudden onsets) have been recorded, commonly
lasting for 1 to 3 minutes.  Several of these bursts have been correlated
with observed ash eruptions, and all are probably associated with emission
of some ash.    Strong gas emission has continued today, with the plume
dispersed downwind.

*     Detailed partial stereoscopic analysis and comparison of crater
photos taken during  overflights on 18 and 20 October has indicated that
the southern vent was substantially deepened between these dates.  The
presence of a lava dome within the crater has not been confirmed.

Conclusions and Alert Status

The present eruption episode is continuing at a reduced level, with
significant gas emission and intermittent small ash eruptions.  
The Alert Level remains at 3.

IA Nairn for
Dr CJN Wilson, Programme Leader, Volcanology