Insight

Building Conservation Network
Period Property Restoration and Conservation

The 6.9 magnitude earthquake that hit Morocco on Friday, September 8 has claimed almost 3,000 lives. A further 5,530 people are injured, and the death toll is expected to rise.

The epicentre was high in the Atlas Mountains. Entire villages have been flattened. Neighbourhoods in Marrakech, the Old City in particular, suffered significant damage.

Much of the media coverage has focused on the region’s traditional architecture. Antonio Nogales, head of Spain’s United Firefighters Without Borders NGO told Reuters that the chances of survival are greatly reduced due to the traditional building materials turning to rubble and not creating pockets of air in the way that steel-and-concrete buildings can when they collapse.

Interviewed by the Washington Post, US earthquake geologist Wendy Bohon said these were not buildings “built to withstand the strong shaking from their base. So they are very likely to collapse and damage like we’ve seen.” These views assume these traditional structures are weak and liable to damage, ill-suited to an earthquake-prone region.

In the immediate aftermath of an earthquake, it is common for local building cultures to be blamed for their own destruction. My research into earth buildings shows, however, how this type of structure is in fact designed to be resilient. Vulnerabilities arise when patterns of knowledge transfer – and the traditional systems of repair and maintenance – are disrupted. Further, when new materials, such as concrete and cement, are introduced, they can be incompatible and so can reduce the buildings’ seismic resilience.

The resilience of earth buildings

Earth has been used as a building material for at least the last 12,000 years. Ethnographic research into earth being used as an element of Aboriginal architecture in Australia suggests its use probably goes back much further.

The huge variety in earthen architecture – which encompasses everything from defensive, religious and elite structures to everyday housing – reflects local geographies, geologies and climates.

There are adobe structures in the American south west and the mudbrick of Mali’s grand mosque in Djenne. Rammed earth or “pise” was used in both Yemen’s 11th-century tower houses in Sanaa and Shibam and 17th-century farm buildings in Switzerland.

The use of cob, meanwhile, stretches from the Great Wall of China to 16th-century houses in south-west England. And turf is characteristic of traditional Scottish, Icelandic, Norwegian, Irish, Greenlandish and Faroese buildings. Used elsewhere as mortar, render, plaster and wall infilling, earth is a resilient material.

These building cultures are uniquely adapted to their locality. In seismic regions in South America and north Africa, in particular, horizontal timbers, fibres or netting are often incorporated to resist the displacement and lateral movement and reduce damage.

In Morocco, both single story and multi-storey houses are constructed from mudbrick, rammed earth (where walls are built up with layers of compressed earth between wooden shutters), stone and timber. More recently breezeblock has been added into this architectural mix. The thermal properties of earth ensure these traditional buildings stay cool in the height of the summer.

A history of mis-characterisation

Too often, building materials wrongly characterised as “primitive” are equated with inevitable destruction. There is a long history of earthen buildings, and traditional construction methods, being labelled as “primitive”.

In colonial accounts of discovery, this characterisation was used as a tool to discredit indigenous cultures and justify what was thought to be the “civilising” influence of colonisation. The British proponents of the Tropical Modernism architectural movement, among others, claimed to have “invented” architecture in West Africa.

This resulted in a shift away from vernacular architecture to colonial architecture and its “new” materials. Earth buildings, today, are still often classified “unsafe” with limited building codes or standards to enable the use of the material. This can be used to justify the shift from traditional building cultures to commercial building materials. You can make money from a bag of cement, but not from a bag of “free” earth.

Across the world – from Mali to the UK – traditional patterns of what ethnographers term “knowledge transmission” have been disrupted. This is made particularly visible within cultural heritage conservation.

When the knowledge and skills required to look after historic buildings, or build new ones using traditional methods is lost, the structures in question become more vulnerable. They can either suffer from inadequate maintenance or alterations – such as replacing earth plaster with concrete render – which makes them weaker.

Elsewhere, repairs from earlier seismic events have not always been made because the loss of traditional skills means no one knows how to do it properly. This can set in motion a negative cycle where structures are then much more vulnerable in subsequent seismic events.

As with the earlier colonial narratives of earth as a primitive material, the news coverage of seismic events needs to be sensitive to the local building cultures. This can lead to local communities being pressured into abandoning traditional methods in favour of modern cement block buildings. If these new buildings are poorly constructed, with little regard to seismic threats, they in turn become vulnerable to further damage.

A large adobe citadel on a hill.
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Arg-e Bam, known as the Citadel of Bam, Iran, which was almost completely destroyed in the 2003 earthquake.
Aliyeh41|Wikimedia, CC BY-SA

Following the 2023 Turkey-Syria earthquake, experts ascribed the extensive damage to recent construction in concrete, steel and brick, that had been undertaken without regard to building codes, not to mention the region’s traditional building culture.

After the 2003 earthquake in Bam, Iran, in which 90% of the urban fabric was damaged and 34,000 people died, there was, similarly, intense scrutiny of the traditional building culture. Yet subsequent studies revealed that the traditional earth buildings, had in fact fared much better than recent restoration work and more modern buildings of breezeblock and cement.

Seismic events are traumatic for local communities at their heart. Failing to understand the resilience of traditional building cultures makes the same communities even more vulnerable.

This article was amended on September 18 2023 to correct a typo in a picture caption which incorrectly placed Bam in Iraq, when it is, in fact, in Iran.

Louise Cooke, Senior Lecturer in Conservation, University of York

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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