Singapore and the big earthquake within 30 years

Scientists warn of big quake, tsunami
Temblor to hit within 30 years, threatening 1 million lives in Sumatra
Amresh Gunasingham, Straits Times 12 Dec 08;

SUMATRA will be ground zero when the next big earthquake hits, an international team of scientists warned.

A massive earthquake measuring 8.8 on the Richter scale will hit within 30 years, generating 10m-high tsunamis and threatening over a million people living along the western Sumatran coast.
'Tidal waves of this height will certainly cause a lot of destruction and displace hundreds of thousands of people living near the coastline,' said Mr Danny Nata-widjaja, co-leader of a project on regional earthquakes and a member of the Research Centre for Geotechnology at the Indonesian Institute of Sciences.
A tsunami will affect more than a million people living along the coastline, particularly in the densely populated cities of Bengkulu and Padang - the provincial capital of western Sumatra which has a population of 400,000.

Although Singapore may feel some tremors, it will not be affected by the quake, the researchers said.

Since 2005, Padang has been hit by more than five earthquakes measuring 6.5 or higher on the Richter scale. The authorities are trying to shore up Padang's defences by improving roads and buildings.

A local government official, Mr Hendri Agung, said that the city is now hampered by the fact that more than half the population is located within 5km of the shore.

'The main road leading up to higher ground is also too narrow to carry out an evacuation process,' he said, adding that the evacuation could take hours.

Ms Patra Rina Dewi, executive director of Komunitas Siaga Tsumai (Kogami), a non-profit tsunami alert community active in western Sumatra, estimates that rescue operators have only 20 to 30 minutes to evacuate the population.

'It is a big problem given the distance from the shoreline...We can safely assume that at least 60,000 people could be lost if a tsunami hits the city,' she said.

The warning comes barely a year after another powerful earthquake in Sumatra, which killed more than 20 people.

Warnings of another tsunami are based on a study led by eminent geologist Kerry Sieh, 57, director of the Earth Observatory of Singapore at the Nanyang Technological University.

Using data from coral reef upliftment - when a quake occurs, coral reefs are lifted above sea level and die, leaving evidence in the coral's growth patterns - the scientists established a geological record dating back 700 years, which shows a pattern of large earthquakes occurring every 200 years.

'Today, there is no other place on earth that has experienced such a close sequence of quakes in over 100 years,' he said.

The study also determined that the earthquake which struck last year was only the beginning of the next big sequence of earthquakes for the 700km-long stretch of the Sumatran coastline.

The findings were published in today's edition of the prestigious journal Science.

Killer tremors since 2000
Straits Times 12 Dec 08;

# Sept 14, 2007

A succession of powerful earthquakes - one measuring 8.4 on the Richter scale - struck Indonesia over three days, causing thousands of people to flee their homes in fear of a tsunami. The death toll eventually rose to 21.

# July 24, 2005

An earthquake measuring 7.2 on the Richter scale hit India's southern Andaman and Nicobar islands and part of Indonesia. No tsunami was caused and there were no injuries.

# March 28, 2005

A powerful 8.7 Richter earthquake struck northern Sumatra in Indonesia. At least 500 people were killed by collapsing buildings on Nias Island.

# Dec 26, 2004

The world's most powerful earthquake in 40 years caused massive tidal waves that destroyed villages and coastal holiday destinations across South Asia and South-east Asia.

The epicentre was located 9.6km under the Indian Ocean south-east of Banda Aceh, Sumatra.

The death toll eventually rose to more than 225,000 people in 12 countries.

The magnitude 9.2 earthquake was the largest since a 9.2 quake struck Alaska in 1964.

# Nov 2, 2002

A powerful earthquake struck close to Sumatra and killed at least two people. The tremors caused flooding, landslides and widespread damage.

Experts put the strength of the quake at between 6.4 and 7.1 on the Richter scale.

The epicentre was located under the sea, south of the coastal town of Manokwari in the Indonesian province of Irian Jaya.

The big one within 30 years
NTU don helps local NGOs plan escape routes, educate public
Ong Dai Lin, Today Online 12 Dec 08;

FOR the past four years, he has been working with Indonesian non-governmental organisations on developing evacuation routes for earthquakes and teaching the public how to rebuild their lives after a tsunami.

Professor Kerry Sieh, director of the Earth Observatory of Singapore in the Nanyang Technological University, warns that an earthquake with a magnitude of 8.8 on the Richter scale may strike West Sumatra within the next 30 years.

Such an earthquake will trigger a tsunami with waves as high as 5 metres, Prof Sieh said.

“There are about 1.5 million people living along the coast who are susceptible to a potential tsunami,” he said.

Cities along the coast of West Sumatralike Padang and Bengkulu are in the path of the tsunami, and the potential loss of lives there could be more than the 90,000 lost in Banda Aceh in 2004 when the Boxing Day tsunami struck, warned Professor Sieh.

Professor Sieh said: “(Indonesian NGO) Kogami has been focusing on developing evacuation routes, teaching neighbourhoods the best way to go, teaching them what to do after the tsunami if they lose their homes.

“There are other NGOs that are thinking about vertical evacuation structures. You build platforms so that the water can go underneath.

“Others, like civil engineers in local universities, are talking about making sure that new buildings (can withstand) the shaking.”

Other parts of Indonesia will be less vulnerable as the tsunami will be directed southwest into the southern part of the Indian Ocean, but islands such as Mauritius are in its path, he said.

Singapore will feel the tremors of the earthquake but will be largely spared from its destructive impact, he added.

Since 2000, Prof Sieh and nine other scientists have been studying the coral reefs of the Mentawai islands, off the coast of West Sumatra.

The growth bands of the ancient coral allow the scientists to study sea-level fluctuations off West Sumatra dating back to 1300 AD.

They found that a sequence of earthquakes happened once in about 200 years and three cycles of the earthquakes have occurred thus far.

Professor Sieh said: “With the Sept 2007 Sumatra earthquakes, we are now entering into the next cycle ...

“If the remaining earthquakes happen as just one event, it will be an earthquake of about 8.8 magnitude.”

“If they happen as a series of earthquakes, the magnitudes could be smaller,” added Professor Sieh.

The team’s research paper was published in the US-based journal, Science.

The team plans to refine its coralreef research and improve its globalpositioning network to better predict earthquakes.

Sumatra quake likely in few decades
Yahoo News 11 Dec 08;

WASHINGTON – Another devastating earthquake along the coast of western Sumatra is likely during the lifetime of many people now living there, researchers are warning.

More than 200,000 died when a quake in that region generated a tsunami across the Indian Ocean on Dec. 26, 2004, and quakes have continued, including a major shock in 2007.
A research team led by Kerry Sieh of the California Institute of Technology reports in Friday's edition of the journal Science that a quake with loss of life and property equal to that of 2004 could occur within the next few decades.

The researchers reached their conclusion studying earthquake history of the region and sea-level changes recorded on corals.

They found a series of events from 1350 to 1380, from 1606 to 1685 and from 1797 to 1833. The 2007 quake seems to be part of a similar pattern, they suggested, but the history is so variable they cannot make an exact forecast.

"Nevertheless, to those living in harm's way on the coasts of western Sumatra, it should be useful to know that the next great earthquake and tsunami are likely to occur within the next few decades, well within the lifetimes of children and young adults living there now," Sieh's team concluded.

Coral may predict future Indian Ocean quake: study
Yahoo News 11 Dec 08;

HONG KONG (Reuters) – A study of Indonesian reefs showed corals record cyclical environmental events and could predict a massive earthquake in the eastern Indian Ocean within the next 20 years, researchers said on Thursday.

The study of corals off Indonesia's Sumatra island showed they have annual growth rings, like those in tree trunks, which record cyclical events such as earthquakes, the scientists said.

"If previous cycles are a reliable guide we can expect one or more very large west Sumatran earthquakes ... within the next two decades," Kerry Sieh, professor at the California Institute of Technology's Tectonics Observatory, told reporters in Singapore.

Scientists said the earthquake could be similar to the magnitude 9.15 earthquake which sparked the devastating 2004 tsunami and left 230,000 people either dead or missing across Asia.

More than 170,000 of those victims were in Aceh on the northwestern tip of Sumatra.

Sieh said while Thailand and Sri Lanka were unlikely to be affected, people in Sumatra should be prepared.

"The tsunami could be at five meters in Padang (in Sumatra). This is a worse case scenario," he said.

Sieh, whose team's research was published reported in Science journal, said corals off Sumatra's Mentawai Islands showed a major earthquake had occurred every 200 years since 1300.

"When earthquakes push the seafloor upward, lowering local sea level, the corals can't grow upward and grow outward instead," the researchers wrote in Science.

Earlier this month, Sieh and his colleagues reported in the journal Nature that an area off Sumatra that has been the source of disastrous earthquakes, still carried a lot of pent-up pressure that could result in another strong quake.

(Reporting by Matthew Webster in Singapore and Tan Ee Lyn in Hong Kong; Editing by Nita Bhalla and Sophie Hares)