The Lochiel Landslip in 2010 and the Significance of Reinforcement Mechanisms

Abstract

The Lochiel Landslip was initiated in August 1974. It was the result of heavy winter rains, but was facilitated by the occurrence of hydrophilic clay interbedded with the quartzitic country rock. Monitoring has shown that whereas most of the minor features within the mass movement have been degraded and subdued, the headwall region remains active. The backing bluff that defines the tension scar has receded between 5 and 10 m during the last decade. The development of fissures some 90 m upslope from the present headwall suggests that this trend will continue. The widening of fissures located laterally and along the hillslope suggests that it too will fail. These changes illustrate the importance of reinforcement mechanisms in landform development. Seepage was facilitated once fissures had formed and the initial slippage left the strata upslope unbuttressed.

Keywords:

• Hummock Range
• Lochiel Landslip
• Proterozoic sedimentation
• monitoring
• reinforcement mechanism

Acknowledgements

The authors thank the Green family, now of Bute, South Australia. They drew our attention to the initial Landslip, which occurs on their property, and continue to facilitate our frequent visits to the feature.