Ruapehu - IGNS - Science Alert Bulletin V95/37

Wednesday 11 October 1995
1600 hours NZDT (UT +13)
Ruapehu Volcanic Activity

Situation Summary
As of 1600 hours the situation is as follows.

The weather conditions today have only allowed minimal observations of the
volcano.

Tremor levels have remained at weak to moderate levels, similar to those
which have prevailed since Sunday.  In the last 24hrs fifteen small
volcanic earthquakes have been recorded, and we only have visual
confirmation of any eruptive activity associated with three of these
earthquakes.

      Observers at Tukino reported 'rooster tails' from the Crater Lake at
about 3pm yesterday (an eruption earthquake was recorded at 1455h, ie
within 5 minutes of the observation).

      Residents of Iwikau Village on the north slopes of Ruapehu reported
minor ash fall between 2330 and 2400h last night, and again during this
morning. An eruption earthquake was recorded at 2318h last night and is
thought to represent the event which caused ash fall 12 minutes later.

      An eruption earthquake at 1452hr today was accompanied by an ash
plume from Crater Lake; it also produced a lahar into the Whangaehu
catchment, which passed the Round the Mountain track crossing at 1531hr.

Summary and Alert Status

No substantial eruptions have occurred at Ruapehu since the 1503h event on
Saturday October 7.  The intensity of volcanic tremor and the continued
small eruption earthquakes indicates that the present eruption episode is
continuing. We advise that the Alert Level remains at 3.

BJ Scott for
Dr CJN Wilson, Programme Leader, Volcanology
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