An investigator from the fire department takes photographs of a large sinkhole that swallowed up part of a dirt track and an olive grove in Kalpaki, a rural area outside Ioannina in northwestern Greece, on Saturday.

The sinkhole is estimated to have a depth of 20-30 meters at least, and an overall surface area of around 200 square meters, and is believed to have been caused by a series of earthquakes that struck the region a week ago.

On October 14, Ioannina was hit by a strong tremor measuring 5.4 on the Richter scale and followed by hundreds of aftershocks, some of them quite powerful.