Mam Tor

This is Mam Tor (Mother Hill) in the Derbyshire Peak District.

The side of Mam Tor has a fantastic example of a rotational landslide.

It’s called a rotational landslide because the bit that moves slides down a curve.

At A, we have the cliff face that has been left behind as the other rock has slid away.

At B, what was a horizontal surface is now tipped backwards towards the hillside.

This messes with the drainage so water may get ponded up.

At C, the debris at the front of the landslide has been pushed into a mess of little hills. (Mam Tor being the Mother Hill)

As you can see from the cliff behind, Mam Tor is made up of numerous rock layers. With a good dose of rainfall to lubricate, the slope becomes unstable.

Movement tends to be in bursts, closely related to periods of prolonged and heavy rainfall, but the average is ¼ metre per year.

So it really wasn’t such a good idea to try to maintain a road across this area.