New Zealand’s Latest Feature: A 6-Story Sinkhole From An Ancient Volcano
If you want to see some big holes, visit Michigan in the spring.
If you want to see the earth disappear into a gaping abyss, you’ll have to fly south.
Geologists have located what is possibly the biggest sinkhole ever recorded in the New Zealand Islands. According to IFL Science, the terrestrial maw could have been left by a volcano that last erupted eons ago.
The 200-meter wide sinkhole is located a little over 9 miles south of Rotorua on New Zealand’s north island. After seemingly appearing overnight, a nearby dairy farmer has been forced to put a fence around the hole so his cows down’t fall in, the Associated Press reports.
“It wasn’t until I came down in daylight that I actually saw just how big it was,” farm manager Colin Tremain told ABC News. “We’ll keep it fenced off as it is to keep stock out, although stock aren’t stupid, they’re not going to walk into a hole, they can spot danger.”
Of course, it’s more than just a massive hole. Scientists are now interested in it for its geological significance.
The hole is at least six stories deep, and three times larger than any other before seen by GNS Science volcanologist Brad Scott, who told the AP that the chasm could have developed over years, as limestone rock under the topsoil degraded into dust.
According to the U.S. Geological Services, there are three types of sinkholes to be found in the world
- Dissolution sinkholes are formed when rain and surface water dissolve carbonate rock underground, forming small depressions.
- Cover-subsidence sinkholes are formed when exposed limestone and carbonate rock are eroded by surface drainage, often resulting in ponds and wetlands.
- Cover-collapse sinkholes like that in New Zealand, develop underground over long periods of time, eventually revealing themselves in a catastrophic collapse.
“Sinkholes are not uncommon in volcanic terrains, particularly those composed of basalts like the lavas currently erupting in the East Rift Zone in Hawaii right now,” Paul Wetmore, an associate professor of geology at the University of South Florida told Live Science.
This could mean the New Zealand sinkhole is evidence of a previously unknown volcano, which scientists are eager to study and understand.
“They’re making a good situation out of a bad event,” said Adam Milewski, an associate professor of hydrogeology at the University of Georgia. “The hard part for all of us is that all of the things we generally like to study are in the ground.”