Natural sinkholes are rare, but researchers in China have just uncovered the largest cluster in the world, 49 of them covering an area of more than 231 square miles.
Government officials in the Shaanxi province in northwest China report the collection of sinkholes was found during a recent survey of land around Hanzhong City.
These tiankengs, as they’re also known, run along a ‘karst’ landform belt in the Qinling-Bashan Mountains of southwest Shaanxi. Karst landforms are the result of soluble rocks such as limestone, dolomite, and gypsum dissipating, tesulting in subterranean drainage systems with sinkholes, caves, and tunnels.
An international team of geologists discovered a chain of 49 sinkholes and more than 50 funnels ranging from 50 to 100 metres (164-328 feet) in diameter.
The holes are spread over four counties. One enormous sinkhole was found, deeper than the Eiffel Tower is tall, and wider than the height of the Empire State Building.
“The largest one was in Zhenba, which had the largest diameter of 520 metres [1,706 feet] and a maximum depth of 320 metres [1049 feet],” Wang Weihua, chief of the Department of Land and Resources of Shaanxi, told China Daily.
It pays to know the ground beneath you. Video: