NEW ZEALAND’S deadly White Island volcano erupted on Monday (December 9) without warning, killing at least six and injuring many more – but why did the New Zealand volcano erupt without raising any alarms?
New Zealand authorities have confirmed the deaths of at least six people, eight are presumed dead and many more are still missing. The active volcano unexpectedly erupted on Monday around 1.11am GMT or 2.11pm local time when dozens of people were on the island. Among those injured by the blast were two British women and tourists from the US, Australia, China, Germany and Malaysia.
Authorities do not expect to find any survivors of the eruption and aerial sweeps of the volcano have not shed any hope on the situation.
On Tuesday (December 10), officials have also warned there is a 50 percent chance the volcano could erupt again.
White Island is one of New Zealand’s most active volcanic hotspots, located in the Bay of Plenty and 30 miles east of North Island.
The volcanic island is a popular destination among tourists thanks to its alien landscape and features.
Since the eruption, New Zealand was also hit a by a magnitude 5.3 earthquake.
White Island’s Monday eruption was a phreatic blast, meaning it was driven by the eruption of scorching steam.
Phreatic blasts typically occur when a source of water passes over molten magma or lava and instantly vaporises into steam.
The rapid buildup of steam and pressure underground triggers an eruption of steam, water, ash and volcanic debris.
Because there was very little lava involved in the actual blast, Professor Oliver Nebel of Monash University in Melbourne argued the eruption did not trigger any warning systems.
The geologist said: “Volcanoes are categorised into extinct, dormant and active.
“White Island belongs to the latter category, as part of the Pacific Ring of Fire – a network of volcanoes along the boundaries of the plates that make up Earth’s outer shell.
“The event on Monday appears to be a phreatic eruption. These types have less molten rock involved and more gas or vapour.
“This causes white smoke as apposed to black smoke.
“The gas that erupted would have ejected very fast – supersonic – is extremely hot and toxic.
“Because there is little lava involved, however, many of the regular warning systems that work on other, larger volcanoes may not have been triggered.”
However, two months before the eruption, New Zealand’s geological monitoring agency GoeNet warned of an increase in steam-driven activity on White Island.
On September 26, volcanologist Steve Sherburn reported “small-scale geyser-like eruptions” of mud and steam.
Some of the scorching jets reached heights of 32ft (10m) but the mini eruptions were not deemed unsafe to tourists.
The GeoNet activity bulletin also noted “they not pose any hazard to visitors to the island and are not a sign of increasing volcanic activity”.
Mr Sherburn said: “Recent measurements made on the island and the continuous data show no change in the monitored parameters outside of the expected signals for minor volcanic unrest.”
Then, just one week before the deadly eruption, GeoNet noted “moderate volcanic unrest” at White Island, suggesting the potential for an eruption.
The volcanic threat level at the time of the bulletin stood at three out of five.
Volcanologist Brad Scott said: “Observations and data to date suggest that the volcano may be entering a period where eruptive activity is more likely than normal.”
Despite the warning, tourists continued to visit the active volcano.
At the time of the eruption, everyone caught in the blast is understood to have been a tourist or tour guide.
Professor Ray Cas of Monash University said: “White Island is in a constant state of unrest and to allow tourists to walk right to the edge of a very active volcano time and time again is incredibly dangerous.”
The regular warning systems that work on other, larger volcanoes may not have been triggered