By Carrie Fellner

Padang earthquake (Image: John Orford)

Experts say poor building construction greatly intensified the devastating effects from the Sumatran earthquake in Indonesia.

In September 2009, schools, hospitals and over 2,000 homes were destroyed as landslides wiped out entire villages and 20-foot waves washed people out to sea.

Professor Michael Griffith and his colleagues from the University of Adelaide, traveled to Padang after the quake and worked with engineers and seismologists from Indonesia to conduct damage surveys in the region.

The team studied almost 4,000 buildings in three weeks.

“For the size of the earthquake, there were quite a few buildings that had pretty major damage. Percentage wise, I guess maybe 25 percent of the buildings had significant damage to them,” Griffith said. “There were some buildings that were less than five years old that had maybe a complete collapse.”

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Mark Edwards, a project leader at Geoscience Australia, oversaw the damage survey and said falling houses and buildings are the most significant contributor to high death tolls in earthquakes.

“One of the problems that was quite evident was the materials used for constructing schools and public buildings, medical facilities, were not up to specification. So the concrete was weak, and we had problems with the masonry infill, where they’ve got brick walls between forming walls, the bricks being quite weak,” Edwards said.

“One member of the team went to a new construction site were there were building a new building and he could actually break the bricks with his hands.”

Edwards said that the lack of strength at the base of the buildings also made the constructions less sturdy and labeled the designs “soft storey behaviour”.

The type of columns and reinforcements used in the buildings meant that when the Sumatran earthquake hit, the top of the buildings were more susceptible to swaying and collapse.

“Now the way we stop that sort of nasty behaviour is that we make sure that that lower floor is stiff enough, so that the defamation caused by the earthquake is spread up through the structure and not concentrated in the lower floor.”

Edwards believes that the modern design specifications should be enforced in Indonesia to prevent similar damage from occurring if another natural disaster were to hit the country again.

“It’s all very well having standards that would lead to quite resistant buildings, but if you don’t enforce them, then they’re not going to happen. Especially if there’s a cost premium, you know, to build things to a higher standard,” Edwards said.

The team also found that human activity in the region heightened the damaging effects caused by earthquakes and other natural disasters.

Dr Damien Kingsbury from Deakin University, said that poor land management practices, and environmental degradation, led to the landslides that wiped out entire villages during the Padang quake.

“If you take trees off a hillside there’s nothing to hold the soil together and when it gets wet it slides down the hill,” Kingsbury said.

“It’s a fairly common problem, basically when there’s nothing, when there’s no root system to hold the soil together on steep slopes, where the soil is fairly fragile, it can drop away very easily.”

According to Griffith, practices such as slash and burn techniques and deforestation may have been responsible for some of the collapses in Padang.

“The collapses I saw were primarily situated down along the port or the river, where the soil conditions were pretty poor and so those buildings being so old and run down and on bad soil conditions, they suffered pretty severely and there was quite a bit of damage down that area,” Griffith said.