Monday 30 December 2013

Fifty meter sinkhole opens up in Peak District, Derbyshire.

A sinkhole 50 m across and 40 m deep opened up near the village of Foolow in the Peak District, Derbyshire, England, early in the morning of Monday 30 December 2013. No buildings were damaged nor any injuries reported, but a power line was broken and had to be re-routed following the event.

The Foolow Sinkhole on 30 December 2013. F Stop Press.

Sinkholes are generally caused by water eroding soft limestone or unconsolidated deposits from beneath, causing a hole that works its way upwards and eventually opening spectacularly at the surface. Where there are unconsolidated deposits at the surface they can infill from the sides, apparently swallowing objects at the surface, including people, without trace.

The precise cause of this sinkhole has yet to be determined, and it under investigation by the British Geological Survey. Much of the Peak District lies on porous limestone which can be eroded away by water percolating through the rock, forming numerous cave systems that are a popular tourist attraction in the area. When such caves reach the top of the limestone layers unconsolidated sediments above collapse into the resulting voids abruptly, creating sinkholes at the surface. The area has suffered high levels of rain over the past week (as has much of the UK), so erosion in such a cave system would not be a surprise. 

The area where the sinkhole opened is also a site of historic lead mining, and it is possible that an abandoned mine could have caved in causing the hole at the surface. Such mine collapses are also more likely in wet conditions, which can weaken mine supports and exposed strata.

The approximate location of the Foolow sinkhole. Google Maps.

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