Ruapehu - IGNS - Science Alert Bulletin V95/34

Sunday 8 October 1995
1700 hours NZDT (UT +13)
Ruapehu Volcanic Activity

Situation Summary

As of 1700 hours the situation is as follows:

The period of very strong low-frequency volcanic tremor which followed the
large eruption at 1503 hours yesterday (Saturday - see Media Release
V95/34) continued until about 2200 hours on October 7.  Tremor levels then
decreased for about 2 hours before again increasing to intense levels
until about 0600 hours today, and then remained at lower but still high
levels until 1100 hours. Since 1100 hours, tremor has decreased to
moderate levels.   No discrete large volcanic eruption earthquakes have
been recorded in the last 24 hours.  Bad weather has prevented
observations of Ruapehu summit today, and no eruptions have been reported
to us.

Conclusions and Alert Status

No substantial eruptions have occurred at Ruapehu during the last 24
hours.  The intensity of volcanic tremor indicates that the present
eruption episode is continuing.  The Alert Level remains at 3.

[Correction: The eruption reported as producing "ashfall and a small lahar
into the Whangaehu catchment" at 1114 h on 7 October (see Media Release
V95/33) appears to have occurred at 1214h.  It was accompanied by a M2.8
volcanic earthquake.  A smaller eruption (M2.7), which is not known to
have produced a lahar, occurred at 1114h.]

Dr IA Nairn for
Dr CJN Wilson, Programme Leader, Volcanology