Indonesia needs earthquake proof houses. Building them is a big challenge



CNN

A deadly earthquake that destroyed buildings in West Java, Indonesia has once again exposed the dangers of living in poorly constructed homes in one of the most seismically active areas on earth.

Since Monday’s quake, survivors have been sleeping rough or sheltering away from homes vulnerable to collapse as aftershocks shake buildings already compromised by the 5.9-magnitude quake that killed at least 271.

The shallow depth of the quake – just 10 kilometers (6 miles) – increased the pressure on structures across West Java, where more than a million people were affected by the extremely strong tremor, according to the US Geological Survey (USGS).

When Indonesian President Joko Widodo visited the site on Tuesday, he promised that damaged homes – more than 56,000 of them – would be rebuilt to be earthquake-resistant.

“The houses affected by this earthquake are required to use earthquake-resistant building standards by the Minister of Works and Housing,” he said. “These earthquakes happen every 20 years. So the buildings should be earthquake resistant.”

But in a developing country where about 43% of the population lives in rural areas, in mostly unsafe and poorly built homes, the task of creating earthquake-resistant buildings remains a huge challenge.

As of Thursday, more than 61,000 people were displaced, according to the National Agency for Disaster Management (BNPB) – and experts say the damage could have been mitigated with the right infrastructure.

A man reacts as rescue workers search for victims in an area hit by landslides after Monday's earthquake in Cianjur, West Java province, Indonesia, November 22, 2022.

Indonesia, an archipelago nation of more than 270 million people, sits along the Ring of Fire – a band around the Pacific Ocean where most active volcanoes lie and most earthquakes occur when tectonic plates push against each other and cause tremors.

Of the 271 people killed in Monday’s earthquake, at least 100 were children, many of whom were at school when the quake struck. A 6-year-old boy was pulled alive from the rubble of his home 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 cave in. Photos showed broken metal scraps, timber and bricks. Most of the dead were crushed or trapped under debris, according to West Java Governor Ridwan Kamil. Others died in landslides.

Cleo Gaida Salima said that when she heard about the earthquake, she tried to call her mother in Cugenang, Cianjur, but when she didn’t answer, she decided to drive there from her home in Bandung on a motorbike.

The journey – about 65 kilometers (40 miles) – usually takes less than two hours. But with roads completely blocked by mudslides, it took every 24 hours.

“All the houses were covered in dirt and 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 out to save themselves. The earthquake was very strong.

Indonesian search and rescue team evacuate bodies from destroyed buildings in Cianjur Regency, West Java Province, November 22, 2022.

In Indonesia, houses were usually constructed of organic building materials, including timber, bamboo and thatch, due to the country’s hot and humid climate.

These were considered sustainable homes and mostly durable in the event of an earthquake. However, increasing deforestation and the high cost of lumber led people to choose other materials, according to a 2009 study on post-disaster reconstruction in Indonesia by The Architectural Science Association.

More and more houses were built from brick and concrete, and although the facade looked modern from below, the construction was poorly held together, the study says.

In addition, low-quality concrete and poor steel reinforcement make these structures increasingly vulnerable to collapse in an earthquake – but cause maximum damage due to the weight of the materials, the report said.

A man stands near houses damaged after an earthquake in Cianjur, West Java province, Indonesia, on November 21, 2022.

Earthquake-resistant structures are designed to protect buildings from collapse and can work in two ways: by making buildings stronger or by making them more flexible, so they sway and slide over shaking ground rather than crumbling.

Architects have been developing this technology for decades, and engineers often adapt materials and techniques to the region.

Architect Martijn Schildkamp, ​​founder and director of Smart Shelter Consultancy, said his company helped build about 20 schools in earthquake-prone Pokhara, in central Nepal, seven years before a major earthquake.

When the earthquake struck in 2015, more than 8,000 people died, but the schools, made of traditional techniques and materials from the landscape, such as broken stone walls, did not crumble.

“Our schools didn’t collapse,” he said. “They suffered only cosmetic damage.

He said that in developed countries like Japan, the knowledge, infrastructure and money are readily available to build earthquake-resistant buildings, but the high cost of building such structures makes it more difficult in developing countries.

In Nepal, many people build their homes with mudstone, which is very brittle, Schildkamp said. “If it is completely unreinforced, there is no additional reinforcement in the house. This is what will collapse very easily,” he said.

Schildkamp’s team used cement masonry and inserted horizontal reinforcement posts into the structure to strengthen it, instead of vertical ones.

Building codes should prevent the proliferation of poorly built structures, but in some countries, governments are not doing enough to enforce the rules, Schildkamp said.

“We need knowledge and orientation in these countries. And we need the government to make these building codes mandatory,” he said.

In West Java, hope to pull more people alive from the earthquake rubble is fading.

Aftershocks also hamper efforts, and residents now live in fear that the next disaster could topple their unstable homes again.

While President Widodo said the government would provide compensation of up to about $3,200 each to the owners of heavily damaged homes, many families in Cianjur lost everything. And now they face the almost impossible task of rebuilding.

Leave a Comment

Your email address will not be published. Required fields are marked *