In this Jan. 2, 2005 file photo, a wide area of destruction is shown from an aerial view taken over Meulaboh, 250 km (156 miles) west of Banda Aceh, the capital of Aceh province, Indonesia. Residents living in tsunami-scarred Aceh province should prepare themselves for a possible repeat of the 2004 disaster, a leading seismologist said, noting historical data indicates tremendous stresses building up along the explosive fault could unleash again anytime within the next half century. (AP Photo/Dita Alangkara, File) |
JAKARTA,
Indonesia (AP)—Seismologists say last week’s powerful earthquake off
western Indonesia increased pressure on the source of the devastating
2004 tsunami: a fault that could unleash another monster wave sometime
in the next few decades.
“The spring was pushed a little bit tighter,” said Kerry Sieh, director of the Earth Observatory of Singapore.
The timing of another megathrust temblor, if it’s on the way, “could have been advanced by a few years,” he said.
Last
week’s 8.6-magnitude earthquake also showed that tsunami-ravaged Aceh
province, close to the epicenter, remains unprepared for the next Big
One. Though the quake caused little damage, the country’s
disaster-management chief acknowledged that evacuation efforts were “a
big mess.”
Indonesia,
located on the “Ring of Fire,” an arc of volcanos and fault lines
encircling the Pacific Basin, has unleashed some of the deadliest
seismic events of the past century. But the 9.1-magnitude quake that
struck in 2004, triggering a 100-foot-high tsunami and killing 230,000
people, caught scientists off guard because its fault, west of Sumatra
island, had long been quiet.
Since
then scientists have conducted a flurry of research, looking at tsunami
sand deposits, uplifted coral and GPS data. By observing past patterns
of quakes, which tend to be cyclical, they better understand what might
happen next, though it’s impossible to make predictions with any
certainty.
The
two last behemoth quakes occurred around 1393 and 1450, and Sieh said
the 2004 earthquake may be just the first part of a similar couplet.
Stresses
loading up on the fault for centuries were relieved only about halfway
eight years ago, Sieh. And last week’s tremor effectively squeezed the
overlapping tectonic plates that form the fault.
“The next megathrust rupture could be in 50 years or in five,” he said. “It’s impossible to know.”
He
said a separate section of the fault, hundreds of miles (kilometers) to
the south, also could snap within the next 30 years, sending a tsunami
slamming into Padang, a low-lying Sumatran city of 1 million.
Last
week’s quake was a “strike slip” quake, which means it thrust from side
to side, not vertically, and therefore did not generate a large
tsunami.
Danny
Hilman Natawidjaja, a geologist with the Indonesia’s Institute of
Science, agreed that last week’s quake piled a small amount of new
stress onto the megathrust, and that “both Aceh and Padang need to be
prepared.”
“Authorities
need to take a good look at what didn’t work well last week and find a
way to fix it,” he said. “Hopefully, this is an opportunity to learn.”
Countries
along the Indian Ocean have spent millions of dollars installing buoys
capable of detecting waves generated by seismic activity, and building
up a vast communications network, from alarms on beaches to systems that
deliver warnings by TV, radio, Internet and mobile phone text message.
But
last week’s quake shows that Aceh has a long way to go, even though
there was almost no damage and the only deaths were from heart attacks.
Had
it been the next Big One, sending waves crashing to shore within 30
minutes, tens of thousands of people could have died in Aceh, where
about three-quarters of the 2004 deaths occurred.
Traffic
was at a complete standstill as the provincial capital, Banda Aceh,
emptied out, people screaming and crying as they piled into cars and
motorbikes to try to get to high ground. Many said that after two hours
they had only moved six miles (10 km). Some finally gave up, abandoning
their vehicles and walking.
“It was a big mess,” said Syamsul Maarif, head of the national disaster management agency.
“What we found out last week … was that evacuations were nothing like the simulations,” he said.
Among
the proposals now being discussed are adding new evacuation routes and
expanding existing roads to high ground out of Banda Aceh. Officials
also are thinking about building more strong, tall structures along the
way so that people unable to get out of town would have better chance of
surviving.
Only
seven buildings, all built with the help of international aid that
poured in after the 2004 disaster, have been set up as emergency
shelters. Maarif said some buildings such as shopping malls, mosques and
schools should be added to the list of possible safe havens.
Associated Press writer Fakrurradzie Gade contributed to this report from Banda Aceh, Indonesia.
Source: The Associated Press