Sep 29 1995, 11:30 am - Ruapehu Volcano

Situation Summary

As of 11:30 the following new information is available:

• Overnight the levels of volcanic tremor has varied within parameters similar to the last six days. Strong low frequency tremor dominated from 14:00 to 22:00 on 28 September. From 22:00 to this reporting time the level has been lower, but still remains elevated above pre‑eruption levels. A large volcanic earthquake (M3.2) was recorded at 08:41 and was accompanied by an eruption column.

• The eruption at 08:41 produced an eruption column to about 6000 m, a lahar down the Whangaehu catchment (observed) and ashfall south of the volcano.

• Eruptive activity at the volcano was relatively quiet through the night, but clearly activity is still continuing.

• Institute staff have been unable to conduct an overflight this morning, due to weather conditions. Views obtained late yesterday (28 September) confirm crater lake is still present but it is considerably smaller than it previously was. Several blocky islets could be observed through the lake surface indicating much of the lake may be relatively shallow. There is still sufficient water to produce lahars as was demonstrated by the 08:41 eruption.

Conclusion and Alert Status

The eruption involving new magma is continuing at Ruapehu. In the light of the activity this morning and the present level of seismic activity, we advise that the Alert Level for Ruapehu remains at Level 4.

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