WELLINGTON, Aug. 8 — Geologists in New Zealand were monitoring two active volcanoes on Wednesday, warning that they could erupt at any time.
Scientists with the government's Institute of Geological and Nuclear Science (GNS Science) said activity at Mount Tongariro, which erupted for the first time in 115 years late Monday, was weak with some steaming vents visible below cloud level.
Explosions at a new vent area below one of its craters had thrown blocks of lava out more than 1.5 kilometers, said a statement from GNS Science.
A brief period of good weather Wednesday morning allowed GNS Science and Department of Conservation (DOC) scientists to make an observation flight around the central North Island volcano, but they could not see above the cloud line.
Previously steaming ground at more than two areas appeared to be more vigorous, said a statement from GNS Science.
"Blocks of old lava and hydrothermally altered lava up to approximately one meter size have been ejected by the eruption. There are extensive areas to the east and west of the new vents where falling blocks have formed impact craters in the ground," it said.
All the block appeared to be angular shapes more typical of existing old rock, rather than fresh lava or scoria.
DOC Ruapehu area manager Nic Peet said in a statement that debris from the eruption had dammed three small tributaries of the Mangatipua Stream, forming three new lakes.
DOC and GNS staff were checking the risk that the water build- up posed to downstream bridges and culverts, he said.
Monday's eruption disrupted domestic flights to towns and cities in the center and east of the North Island on Tuesday, but no further disruptions were reported Wednesday.
Meanwhile, GNS Science reported that a small cone was forming in the lake on White Island, a marine volcano about 50 km off the east of the North Island.
The color of a gas plume coming from the island, which is also a major tourist attraction, had changed from white to light brown, indicating more ash was escaping.
"This is the first time ash has been produced from White Island since 2000 and may represent the start of a new phase of activity, " said a statement from GNS Science.
"Visitors to White Island are now at the highest level of risk since the end of the 2000 eruptions," it said.
GNS volcanologists planned to visit the island this week to assess the situation and take further samples and measurements. (PNA/Xinhua)