VOA News - Jakarta May Be Largely Protected From Indonesia's Deadly Quakes

By Katie Hamann Jakarta 07 September 2009

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As the hunt for those killed in last week's Indonesian earthquake continues, residents of the capital, Jakarta, are wondering if their city could be at risk for bigger, more dangerous quakes. Despite the sharp, frightening shaking that the city experienced last week, experts say massive damage is unlikely.

Indonesian geologist stands near LCD screens displaying one of the aftershocks following a 7.2-magnitude quake, at Meteorology and Geophysics Agency in Jakarta (File)

Jakarta has been rattled by earthquakes on numerous occasions. They may cause pulses to quicken but usually they are greeted with nervous laughter and calm evacuations.

But for some the quake on September 2 was very different. The intensity of the quake, which rocked the city for more than a minute, caught many off guard.

At least 18 people were admitted to hospitals in Jakarta, some of them with injuries sustained as they evacuated buildings. Legs were broken and one person was severely injured during stampede as panicked shoppers and office workers surged out of buildings.

But the crowded city is more fortunate than much of the country, which sits atop tectonic plates that frequently slam together to cause massive earthquakes. Indonesia's 18,000 islands are part of the Pacific Rim of Fire, which stretches from the North and South American western coasts across the Pacific. It is particularly vulnerable to earthquakes, volcanoes and tsunamis.

Jakarta itself does not sit on a geological fault line. Geologists say that means it is likely the city will only ever feel the effects of earthquakes with epicenters more than 100 miles away.

Fauzi, who goes by one name, heads the earthquake and tsunami unit of Indonesia's Meteorology and Geophysics Agency. He says it is unlikely that quakes in the capital would be catastrophic.

"The center of the earthquake is not available in Jakarta," said Fauzi. "What we have is only receiving impact from the source of the earthquake somewhere south in parts of Java."

Fauzi says many people panicked unnecessarily last week and public education campaigns are needed to teach people how to respond to earthquakes.

Jakarta requires buildings over four stories to be able to withstand magnitude 7 quakes.

Adang Surahman, an earthquake engineering expert at Indonesia's Bandung Institute of Technology, says most of Jakarta's high-rises have been built to withstand what scientists refer to as the once in 500-year quake.

"Buildings in Jakarta are built to withstand horizontal acceleration of about 10 percent of gravity and this earthquake which just happened yesterday maybe about five percent of gravity," said Surahman.

Visions of soaring high-rises crumbling may grip the imagination but Surahman says it is the smaller one and two storey dwellings that are most vulnerable in places like Indonesia.

"Majority of buildings in Indonesia are non-engineered buildings, including maybe in Jakarta," added Surahman. "Let's say one-, maybe two-story buildings are not necessarily designed properly. That is my concern."

It is in these dwellings that most Indonesians live and, when large earthquakes strike, often die.

Most of those killed in last week's earthquake died when a landslide triggered by the quake swept boulders as big as trucks across a dozen homes in the village of Cikangkareng. More than 30 people remain missing there.

The government says as many as 88,000 people have been displaced by the disaster.