Jul 26 1999, 3:00 pm - White Island Volcano

Summary

Minor eruptive activity has recommenced at White Island from a new vent to the south of the vents active earlier this year. Volcanic ash was erupted from this vent during the later part of last week and the weekend. Ash emissions decreased significantly on Sunday July 25. A small lake is still present within Metra Crater. Only weak volcanic tremor has been recorded during periods of known the ash emission. During an over flight on Saturday July 24 the steam and gas plume was observed extending over 40 km downwind of the volcano.

The alert level remains at Alert Level 1.

Observations

An overflight was made between 13:40 and 13:52 on July 24. A weakly ash charged steam and gas plume was rising to about 600 m above the active vent, before being blown downwind for over 40 km. The plume carried very minor volcanic ash. Viewing conditions within the Main Crater area were poor, although the local wind was from the south-east at 12 - 15 knots.

Views obtained were sufficient to ascertain that neither PeeJay Vent nor the new vent immediately east of it was the source of the volcanic ash cloud. The ash cloud appeared to originate from an area about 60 - 100 m to the south-west, towards the gully system that drains south-east in to Metra Crater. This active vent was continuously emitting ash. There was no evidence of ash accumulating on the Main Crater floor or on the outer flanks of the cone, indicating no significant ash emission has occurred. There was also no evidence of impact craters.

Tour operators visiting the island on Wednesday July 21, experienced minor ash emissions. While on Friday July 23 several aircraft operators observed a plume extending to 3000 m above the island. Tour operators also report ash emission stop after 08:30 on Sunday July 25.

In summary, minor eruptive activity has recommenced at White Island. With the recommencement of activity the possibility of larger scale eruptions is again present. Hence all visitors to the island should exercise caution.

Brad Scott
Volcano Surveillance Manager