Oct 24 1997, 11:30 am - Ruapehu Volcano

Further to our last update (RUA-1997/13), activity at Ruapehu has remained at low levels. Volcanic tremor levels have been declining with time, but minor reactivations have occurred. These are usually accompanied by volcanic earthquakes. A small eruption accompanied a larger volcanic earthquake at about 9.20 pm on Saturday the 18th. This is the last known eruptive event. A topographic feature which appeared above the crater floor as a block of lava (spine), to the south of the fumarole field reported in RUA-1997/13, was observed on Friday (17th), but was not present on Thursday this week. The significance of this is not clear.

Volcanic tremor levels increased slightly yesterday afternoon, being sustained until about 9 pm. This was followed by a sequence of 14 small volcanic earthquakes. No eruptive activity has been reported with these volcanic earthquakes. Volcanic tremor levels have risen again this morning. As can be seen from the plot below it is weaker than the tremor earlier in this sequence.

The Alert Level remains at 2.

Brad Scott (for C.P. Wood)
Volcanology Section Leader