Scientists have discovered a magma chamber in New Zealand that explains the recent earthquakes in the area. This odd discovery could be the beginning of a new volcano although this is not expected to happen anytime soon.
The buildup contains enough magma to fill 80,000 Olympic-size swimming pools and has squeezed up beneath the surface near a coastal town of Matata, about 200 kilometers southeast of Auckland, according to Geophysicist Ian Hamling, lead author of the study published in the online journal Science Advances.
Hamling assured that the magma remained about 10 kilometers below the surface, so deep enough that he did not expect a volcano to develop within his lifetime. The phenomenon has two possible scenarios, a volcano could develop over hundreds or thousands of years, or the magma could eventually cool and harden, he said.
The findings were qualified as a big surprise by Hamling because there have been none active volcanoes near Matata for at least 400,000, the actives ones were far away in the country. The baby volcano study showed that the molten rock can accumulate underground in complex and unexpected patterns, but this does not indicate that an eruption is imminent, as reported by Nature.
GPS data and satellites images were used by the researchers to study ground motions in the Taupo Volcanic Zone. The region, which goes down the center of New Zealand’s North Island, has seen 25 enormous eruptions over the past 1.6 million years.
Also, the collected data also showed an area of land about 400 square kilometers that have risen by 40 centimeters since 1950. This is also an unexpected finding that the researchers encountered when they were just looking for some information about the volcanic activity.
According to Hamling, there was a period of quick uplift between 2004 and 2011 that likely triggered thousands of small earthquakes. Scientists had previously thought the tectonic shifts were the cause of the earth movements, although the new evidence pointed out that the quakes were likely triggered by magma stressing and breaking rocks.
A 2015 study found that much of the central Taupo Volcanic Zone was subsiding, or sinking, as it is expected after magma erupts and drains from an underground chamber near the volcano. But another northern area along the Bay of Plenty coast seemed to be happening the complete opposite.
“I just discounted it at the time, because we were so focused on looking at the more volcanic part,” Hamling said.
After that, the team eventually took a closer look, taking in data from global positioning stations as well as from geodetic surveys from 1950. It was then when it was determined that the ground had risen by 5 millimeters per year since then, and the amount almost doubled in the 2000s. After 2011 the measures dropped back to the lower rate.
Researchers hope that the findings will encourage or give a practical tool for scientists to develop a warning system for the future earthquakes in the area. About 650 people are living in the Matata town, where the magma chamber is located, and about 10,000 residents in the near city of Tauranga.
According to Elaine Smid, a volcanologist at the University of Auckland, Tauranga is already is a constant danger because the city is close to an active volcano area, where the ashfall comes from the Taupo volcanic. The possible earthquakes could represent a further compromise to the city’s security, even though it is unclear if the magma chamber will directly have any consequences for its citizens.
However, Nico Fournier, a volcanologist with GNS Science, commented that some other geologic process may be at work and can explain the earthquakes based out of the town of Taupo. There has been no increase in volcanic activity in the northern Taupo region.
A “zombie volcano”
Matthew Pritchard, a geophysicist at Cornell University in Ithaca, New York, assured that the study is not the first one to suggest that magma is pushing into Earth’s crust somewhere other than under an active volcano.
Examples have been found in the central Andes, Pritchard said. He addressed the phenomenon as “zombies volcanoes”, due to they showed signs of life when they supposed to be dead.
“Not to be too glib, but we are not undergoing a zombie-volcano invasion,” he added.
The magma chambers could also be found now because the technology has improved satellites’ vision and researchers have a better view of ground movements currently.
Hamling and his team want to continue studying the Bay of Plenty area in detail by using a range of techniques to probe exactly the size and shape of the magma chamber. Half of the surveyed area is offshore, and researchers need to rely on inferences from what happened on the land to gauge the changes underwater, he said.
Source: Science Advances