Jul 20 1996, 9:00 am - Ruapehu Volcano

Volcanic tremor and activity at Ruapehu increased significantly at around midnight. At approximately 07:00, the sustained high tremor level (interpreted to represented continuous activity) which had been recorded for the previous 7 hours, was replaced by small eruption earthquakes with airwaves. These airwaves have produced sonic booms heard in Ohakune, Waikaremoana and Turangi. The sustained tremor level has increased again within the past hour and is punctuated by airwave-producing eruptions.

Pilots of commercial flights this morning have reported ash-charged plumes rising to heights of 20,000 to 25,000 feet (6,100 to 7,500 m) above Ruapehu and on-going light ash fall has been reported from National Park township. Ash fall has been reported overnight in Ohakune and there is a significant coating of new ash on the mountain.

A field party has left Wairakei at 9 am to monitor the ash fall.

This resumption of activity has anticipated based on recent events (see RUA-96/43), and at the time of writing the activity remains at a moderate level, significantly less intense than events of 17 June 1995.

The Alert Level remains at 3.

Bruce Houghton/Carol Bryan (for Brad Scott)
Volcano Surveillance Manager