Re: Geology, Earthquakes & Volcanism News and Discussions
Posted: Sun Jul 11, 2021 10:17 am
The Croatian village where the land became 'Swiss cheese'
https://www.bbc.com/future/article/2021 ... -sinkholes5th July 2021
Villagers in north-east Croatia feared their homes might be swallowed when almost 100 enormous sinkholes appeared in a month. Now scientists are trying to understand if the land that is left is safe.
It happened suddenly and without warning. Where there should have been the emerging first shoots of potato seedlings behind the orchard in Nikola Borojević's spacious garden, there was now huge hole. Measuring 30m (98ft) wide and 15m (49ft) deep, it quickly filled with water. And it wasn't the only one.
Within the space of a few weeks, dozens of similar holes had opened up around the village of Mečenčani and neighbouring Borojovići in north-east Croatia. The one outside Borojević's home in Mečenčani appeared on 5 January, just six days after a 6.4 magnitude earthquake struck the area around the nearby city of Petrinja. It was the strongest earthquake to have hit Croatia for more than four decades, killing seven people and destroying thousands of homes.
While landslides and sinkholes are known to be triggered by earthquakes, along with other strange geological phenomena such as liquefactions – where the solid ground begins to behave like a liquid – the sheer number of holes appearing around the two villages surprised and baffled experts. A month after the earthquake, there were almost 100 sinkholes spread over a 10 sq km (3.8 sq miles) area, with new ones opening every week.
The hole in Borojević's garden is now the largest in the area. When it first appeared it was 10m (33ft) wide, but started to grow almost immediately.