The vast expanse of Lake Taup's sky blue waters evoke an extreme sense of tranquility.
According to a new paper in the New Zealand Journal of Geology and Geophysics, geological unrest is about to start.
Lake Taup is the largest freshwater lake in New Zealand. The lake has a violent origin story.
The lake's waters are located within a prehistoric caldera which was formed during Earth's most recent supereruption.
Earth's surface sinks and the landscape is changed into a caldera when a caldera is formed after a supervolcano releases a lot of material.
The Taup volcano has been active 25 times. According to the new paper, its most recent eruption in 232 AD was one of the Earth's most powerful eruptions. The volcano has had at least four documented episodes of unrest, causing destructive earthquakes and a massive ground subsidence.
The researchers studied up to 42 years of data collected at 22 sites around and across the lake. There is proof that the supervolcano is still moving.
Finn Illsley-Kemp is the lead author of a novel surveying technique which uses the lake surface to detect small changes. The gauge is used to measure the vertical displacement of the lake bed.
To make sure the data is reliable, the gauges are weighted to reduce the impact of waves, and several measures are taken for each data point. There is a backup gauge installed at each site.
The measurement were recorded from just six stations. Between August 1982 and July 1983 there were eight more stations added.
The system detected rising or falling in the early 1980's. The central Kaiapo fault belt was rupturing after a swarm of earthquakes gently shook the region.
Over the past 35 years, seven discreet episodes of unrest have been recorded.
A robust dataset that has only become more detailed over time was created by the routine surveys that were carried out each year with additional sensors.
During periods of geological unrest, the north-eastern end of the lake tended to rise, while the lake bed near the fault belt's center sank.
The volcano in the vicinity of Horomatangi Reefs has caused 160mm of uplift, while the north of the lake has caused 140mm.
He thinks the location of Taup's magma reservoir, which is too hot and molten for earthquakes to occur, is this area.
The researchers think that the 16 cm of uplift is caused by magma moving closer to the surface during periods of unrest.
Taup is an active volcano that is connected to the surrounding tectonics.
The researchers think that the northeastern part of the volcano is more likely to be affected by the expansion of hot magma. They think that the sinking center of the Taup fault and the subsidence at the lake's southern end are related to deep magma cooling.
Illsley-Kemp has assured people that there is no evidence that the volcano will erupt in the near future.
"However, Taup will most likely erupt at some stage over the next few thousand years, and so it's important that we monitor and understand these unrest periods so that we can quickly identify any signs which might indicate a forthcoming eruption," he said.
Understanding the behavior of the caldera is what this research is about.
The study was published in the journal.
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