By Catherine Graue
Sitting at the collision point of several tectonic plates, Papua New Guinea is ranked the 10th most disaster-prone country in the world and is regularly rattled by earthquakes.
But as the developing nation undergoes a rapid period of urbanisation, there are fears buildings are not being constructed to a standard that can survive strong earthquakes — potentially leading to large numbers of casualties.
More than 125 people are estimated to have died in a magnitude-7.5 earthquake on February 26, which struck the country's remote highlands region.
The majority were killed when their houses were buried by landslides.
Those in the industry said PNG's current building standards are outdated and rely on decades-old seismic assessments which underestimate the risk posed by earthquakes.
Traditionally people have built homes made from natural materials with each home built to a style that was designed especially for the landscape.
Houses are built on stilts in flood-prone areas and with heavy thatched roofs to keep things warm in the highlands.
"The traditional buildings in PNG were fairly light structures, which were very flexible, and performed very well in earthquakes," Gary Gibson, a seismologist at the University of Melbourne who has a long association with PNG, told Pacific Beat.
"They usually didn't fall down or if they did, there wouldn't be many casualties, if any."
But PNG's population is booming; it's estimated to have grown from 2 million in 1960 to nearly 8 million now.
People are increasingly attracted to the country's urban areas, as youth seek employment opportunities, where the majority of people live in settlement communities.
Urban drift concerns
They are increasingly building more permanent structures from corrugated iron, rather than traditional homes made from natural materials.
That urban drift has concerned experts.
"Nowadays they're starting to build more substantial buildings and they are much more sensitive to earthquake shaking," Mr Gibson said.
"If the modern buildings are built according to a code they're no problem, but if they're not then a building collapse means casualties.
"Even a moderate earthquake by PNG standards, a magnitude-6 or -6.5 under one of the major cities, [such as] Lae, will have rather tragic consequences."
Building industry insiders say homes in PNG often aren't being constructed following the country's building codes.
"There's a lot of shoddy work going on," Australian builder Richard McGuinness said.
"We work with Catholic dioceses in the Mt Hagen [the largest town in the PNG highlands] area and we've just had to go in there and re-establish two buildings up there.
"I was asked to go in and do a review on the buildings because they started falling down and … we excavated some footings and discovered they weren't built to specifications," Mr McGuinness said, who is the managing director of construction company Hausman Building Solutions.
Mr McGuinness believes construction companies operating in PNG are forced to build "under an honours system" because building boards and physical planning departments rarely operate outside of the capital Port Moresby.
"We are self-regulating, we've got our own engineers and we try to get building board approval, and that's fine," Mr McGuinness, who has worked in PNG for more than 20 years, said.
"They [give the] rubber stamp but … there's nobody here to do an inspection."
Building code dates back to 1980s
PNG's geohazards management division has received Australian assistance in recent years to help it develop a new building code.
The division's acting director, Chris McKee, and his colleagues have worked closely with GeoScience Australia to develop an updated national earthquake hazard map, which will feed into a new building code.
"The current building code actually dates back to the early 1980s but, largely, it adopted New Zealand standards. So it's actually quite robust," Mr McKee said.
"But because of the information available at the time, for the whole of PNG, there were many gaps in the information base."
Mr Gibson said previous assessments underestimated the risk, and points to the recent highlands earthquake as something experts have known was a high risk of happening.
"The old map was based on very limited information and we've known about the Southern Highlands for quite a long while," the seismologist said.
"For 20 years it's been becoming obvious that it is active but not really as active as the subduction areas [in the New Guinea islands region]."
Mr McKee is optimistic their new assessments fill in the gaps.
"The revision of the building code will be informed by the seismic hazard assessment that we did, so we can give this information to architects and engineers so that they can design appropriately for any part of Papua New Guinea," he said.
Lessons to learn from Chile
Experts acknowledge the new regulations alone won't ensure buildings can stand up to earthquakes.
"Most developing countries go through a phase, it takes a while to get the code firstly written and then especially followed and enforced," Mr Gibson said.
But he thinks there are lessons PNG can learn from another quake-prone country.
"In Chile, people themselves understand that it's a good idea to build properly and people building buildings expect their designs to be resistant to earthquakes," he said.
"If you're building a large major structure, you would follow a code like we would in Australia.
"But if you're building a house, or something where you're not going to specifically do an earthquake calculation, what you come up with is a set of rules to follow for building that [structure] to be resistant to earthquakes.
"A local set of rules … can be produced that will help enormously in reducing the damage in an earthquake."
- Australian Broadcasting Corporation
- © ABC