Scientists are baffled by the rapid appearance of over 100 sinkholes in Croatia.
The unprecedented phenomenon began after two massive earthquakes struck central Croatia in December 2020. The earthquakes were 5.2 and 6.3 on the Richter scale and killed seven people near the town of Petrinja.
Scientists believe the geological events triggered the chasms but what’s perplexing is the speed at which the sinkholes are developing.
“Experts say that these sinkholes would have formed naturally anyway over time, but the earthquake acted as sort of a catalyst which sped up the whole process, unfortunately. And then we saw smaller sinkholes appearing in the ground,” Nenad Tomasevic, a local, told the Associated Press.
It typically takes sinkholes decades or centuries to form in areas rich with limestone deposits. The holes, some of which are under houses, have forced residents to evacuate. Even farmers are now afraid to work the land in fear of being swallowed by the ever-growing holes.
Meanwhile, low-level tremors are continuing to force more sinkholes to open up. The environmental impact, along with the pandemic lockdowns, has made life difficult for the local subsistence farmers who rely on corn and potato crops. Thus far, the largest sinkhole is 30 meters wide and some are as deep as 15 meters.
Scientists from Italy and Slovenia are working with experts to get to the bottom of the issue. The unusual development will allow them to study how earthquakes and other geological events can affect sediments and groundwater.
“We plan several methods [of exploration) here. We have already performed some geophysical profiles, seismic and also electrical. We plan to do maybe magnetotelluric (electromagnetic) methods here,” Josip Terzic, a hydrogeologist, told the Associated Press.
“We will have a site scan screening of this biggest, largest sinkhole, to map the underwater morphology of it. As far as I know, it’s approximately 12 meters deep under the water here,” Terzic added.