Stonebarrow Hills, Dorset

Landslide case study

Stonebarrow Hill, Dorset location map
Information icon

Stonebarrow Hill, Dorset location map.

Expand icon

This landslide complex (Figure 1) is to the east of Charmouth in Dorset and parts of this site are sometimes also known as Fairy Dell and Cain’s Folly. This landslide is well known as one of England’s largest and most active landslide complexes, alongside that of the Black Ven landslide immediately to the west of it, and is a National Trust coastal site. National Landslide Database ID 840/1.

Figure 1 Evans Cliff Landslide, a landslide on the western flank of Stonebarrow Hill.
Information icon

Figure 1 Evans Cliff Landslide, a landslide on the western flank of Stonebarrow Hill.

Expand icon

The cliffs are very high at the centre of the complex (140 m). A major landslide event occurred in 1942, a further movement in 1968, and more recently, a significant re-activation consisting largely of mudslides took place in December 2000. This resulted in closure of the coast path along the main backscarp. Movement continues at this site.

Geology and landslide trigger

The landslide mechanism is dominated by multiple retrogressive rotational movements and mudslides/mudflows. As at Black Ven, these act in the upper part of the slope (Gault Formation overlain by Upper Greensand Formation), the mudslides draping over the ‘middle’ bench (Dyrham Formation), and the lowermost unslipped sea-cliff bench of Lias Group (Belemnite Marl and Black Ven Marl Members) mudstones and onto the beach. The upper part of the slope is formed in the Upper Greensand and Gault Formations overlying the Dyrham Formation. The Stonebarrow Hill complex has been described in the literature (Brunsden & Jones, 1976; Lee & Clark, 2002).

The main part of the landsliding at Stonebarrow Hill is occurring in the upper and middle sections of cliff. Major re-activation of this part of the landslide took place on 28 December 2000, during which large slumps generated mudflows and debris flows, which cascaded over the lower cliff and deposited onto the beach (Figure 2). The remains of these were still visible after two years, but had almost completely disappeared by 2003. The landslide was caused by unusually high rainfall from mid-August to late December 2000, during which time 700 mm of rain fell at the Pinhay weather station near Lyme Regis.

Figure 2 Falls from beneath a thin limestone bed in the lower cliff of the Black Ven Marl Formation.
Information icon

Figure 2 Falls from beneath a thin limestone bed in the lower cliff of the Black Ven Marl Formation.

Expand icon

Survey

As part of a cliff monitoring programme at BGS, data has been collected from the cliffs at Stonebarrow. The principal method of survey is long-range terrestrial laser scanning (terrestrial LiDAR) — see Terrestrial LiDAR Survey Techniques.

Series of photographs from 2008

The site was revisited in December 2008 and the following photographs were taken:

Photo gallery

Contact the Landslide Response Team

Tel: 0115 936 3143 Email: landslides@bgs.ac.uk

You may also be interested in:

fall at Pennington Point. (Photo: © Eve Mathews)

Landslide case studies

The landslides team at the BGS has studied numerous landslides. This work informs our geological maps, memoirs and sheet explanations and provides data for our National Landslide Database, which underpins much of our research.

Show more
Storegga landslide

Landslides in the UK and around the world

BGS maintains the National Landslide Database, with over 16 500 records, and is the definitive source of landslide information in Great Britain.

Show more
Debris flow on A83

Understanding landslides

What is a landslide? Why do landslides happen? How to classify a landslide. Landslides in the UK and around the world.

Show more
Holbeck Hall Landslide

How to classify a landslide

Landslides are classified by their type of movement. The four main types of movement are falls, topples, slides, and flows.

Show more

Was this page helpful?

  • How can we make this section better?*

  • Please select a reason*

  • How can we make this section better?*