Jul 9 1996, 2:00 pm - Ruapehu Volcano

Overnight activity continued from the active vent in the south part of the summit crater. The level of seismicity associated with the activity has also varied overnight. The level of seismic activity decreased through to about 19:00 (Monday evening) and remained lower until 22:00, when discrete explosion events started to reappear on the seismic records. Explosion earthquakes were occurring every three to five minutes, and continue at this time, but are becoming weaker.

A fixed-wing overflight was made from 12:00 to 12:30. Activity at the volcano consisted predominantly of small ash poor events, which occurred every 3 - 5 minutes. They jetted ash and blocks to about 100 m above the vent, and feed an ash poor plume which is rising to about 3300 m (11,000 feet) before being blown off to the east. The plume is ash poor, and little ash fall is expected while this condition continues. The plume is however gas and steam rich and will produce a vog (volcanic fog) situation. Observations from todays flight and the seismic signals suggest the Strombolian type eruptions are declining.

An attempt is been made to make a COSPEC flight

The seismicity accompanying today's activity is similar to that recorded yesterday afternoon. This level and style of activity is consistent with an alert level of 3.

We advise the alert level remains at level 3.

Brad Scott (for Colin Wilson)
Volcanology Programme Leader