Investigating bedrock landslides in the Atlas Mountains of Morocco

Professor Anne Mather is researching this natural hazard in the Saharan margins

I am currently working on a research project, funded by a Thesiger-Oman Fellowship from the Royal Geographical Society, in the arid Saharan margins of the High and Anti-Atlas Mountains of Morocco.

This project is investigating the occurrence and timings of large (kilometer-scale) bedrock landsliding.

Landsliding is essentially the collapse of a slope, and bedrock describes the material that makes up the landslide – in this case it is mostly composed of solid rock.

This project will examine the nature of the hazard today and under past climate regimes to better understand the impact of changing climate and human intervention on these large and previously unstudied slope instabilities in the NW Saharan margin.

I first developed an interest in geomorphology as a young child. I was always wanting to know how the landscape had come to be, a bit like a detective trying to piece together a crime scene - the landforms were the clues.

Landslides in the river valleys

This project came about because of our University of Plymouth research team from SoGEES (School of Geography, Earth and Environmental Sciences) were undertaking an investigation of the evolution of the river valleys, and we started to notice lots of large unreported landslides within the river valleys.

No-one knew they were there or how old they were, and yet in many cases, these landslides lay adjacent agricultural fields and nearby villages in the valley floors, indicating a considerable risk to the local community who live and work there.

The landslides pose a risk in terms of the actual slope failure and also their potential to block the river valleys. Where this happens, there is the potential for lakes to form behind the landslides which can be suddenly released when the landslide dam weakens, creating an enhanced flooding risk downstream.

University of Plymouth students on a field trip analysing a landslide with a hotel built into it, Dades river Valley, High Atlas Mountains.

Landslide (right-hand side of valley) above agricultural fields and village in the High Atlas Mountains.

How do you investigate a landslide?

To carry out this research we undertake analysis of satellite imagery and digital elevation models (DEMs) of the landscape. However, many of the landslides in the High Atlas Mountains are difficult to recognise using this approach alone as their morphology is very subtle. So we obtain higher resolution data using ground mapping with GPS and laser technologies.

We typically use aerial drones to create 3D surveys of the sites, although this has proved problematic in Morocco as UAVs are banned, and we are in the process of seeking special permissions.

We can combine the survey data and rock samples for material strength analysis to determine how the landslide failed, and also take samples from suitable sites to enable an age range to be placed on the landslide activity.

Experiencing local life in the Atlas Mountains

We get around in the field through a combination of 4x4, walking and in some cases need to access sites via a canoe along the river. On a recent field season, we hired a ‘standard’ 4x4 vehicle for the first time (an open pick up) with local number plates. Prior to this, we had always had vehicles that had government plates.

Without the government plates we had a totally different experience. We became more approachable and a curiosity, so it wasn’t long before we seemed to be the rural taxis. If we stopped or slowed down, people would hop on the back to have a lift. On one morning we gave the local teachers a lift into one of the villages as they would live in the village for the week and return to their homes at the weekend. As highly respected and valued members of village life, through the teachers we experienced a glimpse into the value of education in these rural communities.

The most memorable moments of this research for me revolve around interactions with the local people, such as the early morning singing of the Amazigh (Berber) women as they collect wood from the sides of the canyons, treading treacherous paths in flimsy sandals. Their sounds fill the valley.

Sharing research with students

We share the research we have undertaken across a number of modules in Geography and Geology that examine natural hazards, landscape evolution and desert environments.

Some students may undertake remote analyses of these landslides for dissertation research projects as part of their degree, and we have had students undertaking hazard analysis of the field sites in the High Atlas Mountains as part of residential field trips to the region.

Our Moroccan academic colleagues with our PhD student Jesse Zondervan and the teachers in the ‘rural taxi’ pick up.

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