EARTHQUAKES RESILIENCEMorocco: Building with Earthquake Resilience
Quakes kill relatively few, but the resulting building collapse kills many more. How do we keep people safe in their own homes?
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, 2023, an earthquake struck under the Atlas Mountains, with the epicenter roughly 75 kilometers (45 miles) 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 around them.
At least 2,901 people have died from the after-effects of the earthquake, Morocco’s interior minister said on Tuesday, and more than 5,500 have been injured.
As officials scrambled to rescue people trapped under buildings in remote villages dotting the Atlas, that figure was expected to rise.
The last time Morocco suffered a similar quake was in 1960 in Agadir, where 12,000 died.
How Do Earthquakes Cause Buildings to Collapse?
The high toll of the September 8 earthquake 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 have said a lack of disaster-resilient infrastructure and poor town planning could have played a big role in raising the causality 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 United States.
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 serve as barriers to the scorching heat. These houses are designed with extreme temperature resilience in mind, but can’t 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, a nonprofit that promotes better design for buildings in earthquake-prone areas.
It added 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 in February 2023.
How Can We Make Buildings Resistant to Earthquakes?
While earthquakes can’t 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 said.
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-printed concrete will allow builders more customization, 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.
Edited by: Fred Schwaller
Sushmitha Ramakrishnan is a DW journalist. This article is published courtesy of Deutsche Welle (DW)
