Morocco earthquake: What makes buildings resilient to the disaster?

Quakes kill few, but resulting building collapse kills many more. How do we keep people safe in their own homes?

A woman sits sadly by the rubble of destroyed buildings in the aftermath of the deadly 6.8-magnitude September 8 earthquake in Morocco. While earthquakes can’t be prevented, the ways buildings are constructed can help to mitigate deaths and injuries during an earthquake and its aftershocks. | Photo Credit: FADEL SENNA/AFP

The primary cause of death in an earthquake is not the shaking ground, but crumbling roofs, crashing walls, and collapsing buildings. This has been the case historically and as well in Morocco. On the night of September 8, an earthquake struck under the Atlas Mountains, with the epicenter roughly 75 kilometers away from Marrakech, a popular tourist destination.

The quake’s magnitude was 6.8 and the ground in the region shook violently. The internet is full of videos of panic-stricken people rushing in and out of narrow alleys as buildings powder down into crushing debris. 2,901 people have died from the after-effects of the earthquake, Morocco’s Interior Minister said on September 12, and more than 5,500 have been injured.

As officials scramble to rescue people trapped under buildings in remote villages dotting the Atlas, that figure is still rising. The last time Morocco suffered a similar quake was in 1960 in Agadir, where 12,000 died.

How do earthquakes cause building collapse?

The high toll of the current quake on September 8 was partly because of the timing of the event. As the quake struck close to midnight, many of the victims were fast asleep, tucked away in their homes. On the other hand, experts say a lack of disaster-resilient infrastructure and poor town planning could have played a big role in raising the casualty rate.

Traditional construction methods used in many parts of Morocco and the old buildings there were not regulated for disaster resilience—and cannot handle an earthquake of this scale, according to Mehrdad Sasani, a professor of civil and environmental engineering at Northeastern University in the US. A major problem in Morocco was the usage of mud-brick construction and masonry that did not have “reinforcement”, he told DW.

Materials like concrete, gravel, and mud are preferred in Morocco as they stand barrier to the scorching heat. These houses are designed with extreme temperature resilience in mind, but cannot withstand earthquakes very well. “Due to their rigid construction and limited capacity to absorb the energy of strong ground-shaking, these structures are at risk of collapse,” according to the US Resiliency Council.

They add that non-ductile concrete buildings make up most earthquake losses around the world. Similar problems caused such mortality and injury rates in the Turkey-Syria earthquakes that took place earlier in 2023.

How to make buildings resistant to earthquakes?

While earthquakes cannot be prevented, the ways buildings are constructed can help to mitigate deaths and injuries during an earthquake and its aftershocks. “There are a few important steps that need to be taken to improve the earthquake resistance of [mud and gravel] structures: Higher quality materials, reinforcement, and improved workmanship and good building layout,” said Sasani. Using a quality-controlled mixture of clay and sand, and “adding straw will help controlling micro cracks”, he said.

However, this structure must be reinforced by a frame made from flexible materials like bamboo or steel. Steel, for example, bends considerably before breaking, therefore strengthening larger buildings against quakes. Earthquake-prone Japan, for example, has been using steel to provide earthquake-resilience in buildings since 1923.

Quake resilience innovation

What new innovations in quake resistance could help Morocco rebuild with greater earthquake resilience? The World Economic Forum recommends buildings to be fitted with “base isolation” systems to separate the building from its foundations using springs or runners.

“This means that when an earthquake starts, the resulting movement will not impose stress on the structure of the building,” the forum says. Many buildings in Japan and Chile use this technology. The costs of such constructions are often prohibitively high, so other countries have been looking for simple and cost-effective strategies against quake damages.

Nepal, another country affected by frequent earthquakes, is using one technique of blending affordable materials like straw bales, used tires and plastic bottles into construction techniques.

Elsewhere in Africa, the South African Housing & Infrastructure Fund will implement concrete 3D-printed houses that are both earthquake resilient and cost-effective. 3D printing the concrete will allow builders more customisation including designing structures that can handle erratic forces caused by an earthquake.

Given that building damage is the leading cause of death in an earthquake, implementing smart building engineering will not only save property and infrastructure from collapse, but most importantly, it would save lives and prevent injury.