Community ready for Tongariro

Scientists have developed three possible eruption scenarios for Mt Tongariro, while locals have formed an evacuation plan should disaster strike.

The most likely scenario for the next seven days is that there will be no further eruptions, GNS volcanologist Steven Sherburn said in a statement this afternoon.

The second most-likely scenario was that another eruption similar to what occurred on August 6 would follow, and the least-likely scenario was that a larger eruption would occur.

If Mt Tongariro's Te Maari crater rumbles into life again, then the families living closest to it have an action plan to refer to, Taupo Civil Defence emergency manager Phil Parker said.

About 46 people live closest to the volcano, on State Highway 46. The families, which have since returned to their homes after leaving them last Monday night, would alert Parker and the Department of Conservation should the volcano erupt, or show signs that it may do so.

They have designated one of their own to co-ordinate the community response should they face an emergency, Parker said.

"They make that call initially because until we get down there and see the magnitude of it, it's community helping community."

They would evacuate to Hirangi Marae in Turangi if it was needed.

Emergency services, DOC, Civil Defence, New Zealand Transport Agency and district health boards met on Friday to discuss the plan. They would meet again tomorrow to update the situation, Parker said.

Road signs warning people of a volcanic hazard were erected along SH 46 in the weekend, but many seem to be ignoring the warnings as they stop to take photos, Parker said.

The volcano could erupt without warning so motorists were urged to continue driving rather than stopping to get a picture, he said.

Seismic activity underneath Tongariro and White Island, off the coast of Whakatane, has calmed in recent days, Sherburn said. The assessment of the most-likely scenarios was only valid for the next seven days and could be adjusted if things changed.

There were reports in the weekend that lahars had crossed the northern foot of Tongariro, but there had been no sightings since. There were some concerns that debris from the eruption, which was blocking two small streams, could produce larger lahars and GNS would be assessing the likelihood of this, Sherburn said.

People located south of Tongariro also reported smelling Hydrogen Sulphide gas over the weekend, which could produce some breathing difficulties.

Further tests have added weight to the theory that last week's eruption was predominantly gas-driven, but the involvement of magma in the future could not be ruled out.

Meanwhile, a plume of ash and steam continues to envelope White Island, but GNS has reduced its warning for pilots.

Visitors to New Zealand's largest and most active volcano were still at the highest level of risk since the 2001 eruptions.