WELLINGTON, Sept. 20 (Xinhua) -- The alert level at New Zealand's Taupo Volcano was raised to Level 1 for the first time on Tuesday.
Although this is the first time the volcanic alert has been raised to Level 1, this is not the first volcanic unrest at Taupo, said GeoNet, which provides geological hazard information for New Zealand.
"There have been 17 previous episodes of unrest over the past 150 years. Several of these were more severe than what we are currently observing at Taupo," said a GeoNet statement.
GNS Science Volcanology Team Leader Nico Fournier said none of these episodes, or the many other episodes which would have occurred over the past 1,800 years before written records were kept, ended in an eruption.
The last eruption at Taupo Volcano was around 232 AD, Fournier said. "The chance of an eruption at Taupo remains very low in any one year," he said, adding the minor volcanic unrest has been causing the ongoing earthquakes and ground deformation at Taupo Volcano since May 2022.
GNS Science, through the GeoNet program, continually monitors Taupo Volcano and other active volcanoes for signs of activity.
"While some of the earthquakes may be felt in areas around Lake Taupo, the deformation is currently only detectable by our sensitive monitoring instruments," Fournier said.
The earthquake sequence beneath the central part of Lake Taupo has continued, he said, adding almost 700 minor earthquakes, mainly at a depth of 4 to 13 km beneath the lake, have now been located.
"We interpret the ground uplift and earthquake activity to be caused by the movement of magma and the hydrothermal fluids inside the volcano. We have also sampled springs and gas vents around the lake for changes in chemistry that may be related to the earthquake and ground uplift," Fournier said.
While Volcano Alert Level 1 is mostly associated with environmental hazards, the potential for eruption hazards also exists, he said.