In Aotearoa New Zealand, we use a volcanic alert level system to describe how active volcanoes are.
Volcanic alert level one means minor unrest. And in the volcanic alert level system, it is the lowest level of unrest at a given volcano.
Lake Taupō, until very recently was at volcanic alert level zero. So why are we changing the volcanic alert level to one at Lake Taupō?
One of the key things is over the past few years, we've really started to understand better what volcanic alert level one means at Lake Taupō Volcano, and with the current level of activity that we've recorded, the earthquakes and the ground deformation, we feel it is appropriate to set the alert level at one.
Behind me is Lake Taupō, and when we mention Lake Taupō, people think about very very large eruptions. There has been some large eruptions, like 30,000 years ago that created a huge crater now filled with this lake.
And then later on, 1800 years ago, another big eruption created another of those calderas inside the bigger one. But the reality is that the vast majority of the eruptions at Lake Taupō are actually quite small.
Over the last 29 eruptions, only two of them were actually large. All the other eruptions were very small size, probably similar to what happened to Ruapehu in 1995, 1996.
Lake Taupō, like most large volcanoes go through some quiet periods and periods with a bit more unrest. When we've got those periods of unrest, we start to see more symptoms.
At the surface, we see some earthquakes. We also see the ground deforming slightly. Not something that people can usually see, but something that we can measure with our monitoring network.
Since May 2022, we have recorded about 600 earthquakes in the lake area. Some of them were actually big enough to be felt by people. The vast majority of those earthquakes were actually quite small and wouldn't be felt, but they would be recorded by our instrumentation.
So remember, if in the future you feel one of those, drop, cover and hold. In addition to being a large volcano,
Lake Taupō is also crossed by a number of really big faults which are crossing the whole region, what we call the Taupō Volcanic Zones. And when we do have earthquakes occurring inside the lake, they are either occurring
along some of those faults or they are occurring around the body of magma, those molten rocks that we know exist under the surface at depths since the last eruption.
So a key thing for us as we try to understand what those earthquakes actually mean during those periods of earthquakes, is to try to understand where they occur and what process they actually related to.
And we keep monitoring the volcano and we will keep you updated on the activity.