CNN
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A deadly earthquake has turned buildings to rubble in West Java, Indonesia has once again exposed the dangers of living in poorly built homes in one of the most seismically active regions on the planet.
Since Monday’s quake, survivors have had to sleep temporarily or in shelters away from vulnerable homes as aftershocks rocked buildings already hit by the quake 5, 9 on the Richter scale killed at least 310 people, according to the head of the National Disaster Management Authority (BNPB).
Lieutenant General Suharyanto said 24 more people were still missing.
According to the United States Geological Survey (USGS), the quake’s shallow depth – just 10 kilometers (6 miles) – put additional pressure on structures across West Java, where more than a million people are displaced. suffered very strong shocks.
Visiting the site on Tuesday, Indonesian President Joko Widodo promised that damaged homes – more than 56,000 of them – would be rebuilt to be earthquake-resistant.
“The homes affected by this earthquake were required by the Minister of Public Works and Housing to use earthquake resistant building standards,” he said. “These earthquakes happen every 20 years. So the houses have to be earthquake resistant.”
But in a developing country, where about 43% of the population lives in rural areas, in poorly constructed and unsafe homes, the task of constructing earthquake-resistant buildings remains a daunting task. big challenge.
As of Thursday, more than 61,000 people have been displaced, according to the National Disaster Management Authority (BNPB) – and experts say the damage can be mitigated with the right infrastructure.
Indonesia, an archipelagic nation of more than 270 million people, lies along the Ring of Fire – a strip that encircles the Pacific Ocean, where most active volcanoes and most earthquakes occur when plates tectonics collide with each other, causing tremors.
Of the 310 people killed in Monday’s quake, at least 100 were children, many of them at school when the quake struck. One 6 year old boy was pulled from the wreckage of the house two days later, but many others were not so lucky.
The earthquake shook the foundations of buildings, causing concrete structures to collapse and roofs to collapse. The photos show pieces of metal, wood and broken bricks. West Java Governor Ridwan Kamil said most of those killed were either crushed or trapped under the rubble. Others were killed in the landslide.
Cleo Gaida Salima said that when she heard about the earthquake, she tried to call her mother in Cugenang, Cianjur but didn’t pick up, so she decided to ride a motorbike from her home in Bandung there.
The journey – about 65 kilometers (40 miles) – usually takes less than two hours. But with roads completely blocked by landslides, it took her 24 hours.
“All the houses are covered in mud,” she said, adding that she was reunited with her family who survived the earthquake.
“We all cried with emotion and happiness,” she said. “Our whole family immediately ran to the rescue. The earthquake was very strong.”
In Indonesia, houses are traditionally built from organic building materials including wood, bamboo and thatched grass, due to the hot and humid climate in the country.
These are considered sustainable homes and are largely durable in the event of an earthquake. However, increased deforestation and high wood prices have led people to choose alternative materials, according to a 2009 study on post-disaster reconstruction in Indonesia from the Association of Architectural Sciences.
The study says more and more homes are being built of brick and concrete, and while the facade may look modern, underneath, the construction is very poorly interconnected.
What’s more, the low quality of concrete and poor reinforcement make these structures increasingly vulnerable to collapse during earthquakes – while causing maximum injury due to the weight of the material, the report said.
Earthquake resistant structures are designed to protect buildings from collapsing and can work in two ways: by making buildings more solid, or by making them more flexible so they shake sway and slide across the shaking ground instead of collapsing.
Architects have been developing this technology for decades, and engineers often adapt local materials and techniques to the area.
Architect Martijn Schildkamp, founder and director of the consulting firm Smart Shelter, says his firm has helped build about 20 schools in Pokhara, an earthquake-prone region, in the region. central Nepal, 7 years before the great earthquake.
When the earthquake hit in 2015, more than 8,000 people were killed, but the schools, built from traditional techniques and materials from the landscape, such as rubble brick, did not collapse. to pour.
“Our schools are not collapsing,” he said. “They just suffered some cosmetic damage.”
He said that in developed countries like Japan, knowledge, infrastructure and money are always available to build earthquake-resistant buildings, but the high cost of constructing such structures makes it difficult to build. construction becomes more difficult in developing countries.
In Nepal, many people build their houses with mud mortar, which is very brittle, Schildkamp said. “If it was completely unreinforced, there would be no further reinforcement in the building. This is something that would fall apart very easily,” he said.
Schildkamp’s team used cement mortar and inserted horizontal reinforcing piles into the structure to strengthen it, instead of vertical piles.
Schildkamp said building regulations should prevent the proliferation of poorly built structures, but in some countries the government is not doing enough to enforce these rules.
“We need knowledge and strategy in these countries. And we need governments to enforce these building codes,” he said.
In West Java, hopes of pulling more survivors out of the earthquake’s rubble are fading.
Aftershocks are also complicating efforts, and residents are now living in fear of the next disaster that could once again knock down their unstable homes.
While President Widodo said the government would pay about $3,200 to each owner of severely damaged homes, many families in Cianjur have lost everything. And now, they face the almost impossible task of rebuilding.
