Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Education and Planning Cut Death Toll in Samoa Tsunami

06.11.2009
Community-based education and awareness programs minimized the death toll from the recent Samoan tsunami, though there are still ways to improve the warning and evacuation process, according to a team of researchers that traveled to Samoa last month.

The team, funded by a National Science Foundation (NSF) grant, collected data Oct. 4 through Oct. 11 to document the impacts of the 8.1 earthquake and the ensuing tsunami that occurred on Sept. 29. They examined flow depths, run-up heights, inundation distances, sediment depositions and damage patterns at various scales.

“In addition to timing – the fact that the tsunami struck in the daylight morning hours when most people were on their way to work or school – tsunami education, awareness and evacuation exercises really contained the death toll,” noted Hermann Fritz, one of the principal investigators and an associate professor of civil and environmental engineering at the Georgia Institute of Technology. “The technical solution doesn’t always work for coastlines near the epicenter with less than 30 minutes between earthquake and onslaught of the tsunami. Earthquakes with durations of more than 30 seconds serve as a natural warning, resulting in a spontaneous self-evacuation.”

Nearly 190 people were killed in the tsunami, with the majority of deaths reported in Samoa, a country governing the western part of the Samoan Islands in the South Pacific Ocean. The two main islands of Samoa are Upolu and Savai’i. American Samoa, a territory of the United States southeast of Samoa, is comprised of main island Tutuila, the Manu’a Islands, Rose Atoll and Swains Island. The Samoan government estimates the total damage from the tsunami at $147 million.

The team’s survey circled all of the main Samoan islands and spanned 350 kilometers from Ofu in the east to Savai’i in the west. The researchers learned that the tsunami impact peaked at Poloa near Tutuila’s western tip and Lepa at Upola’s southeast coast. Maximum run-up heights reached 17 meters at Poloa, and inundation distances and damage were recorded at Pago Pago, more than 500 meters inland. The harbor at Pago Pago, well-protected from ordinary storm waves, is vulnerable to long-period tsunami waves.

In addition, researchers noticed a marked difference between the evacuation process in Samoa and American Samoa. While most villagers in Samoa knew to rapidly evacuate after experiencing an earthquake, only a month earlier they had been told that cars help with evacuations, a deadly directive since most roads run parallel to the beach.

“Many perished trapped inside cars waiting in congested small roads or in long lines behind vehicles stopped by landslides or debris on the road,” said Costas Synolakis, principal investigator and professor of civil engineering at University of Southern California. “I have been on more than 20 tsunami field surveys, and in many ways this was one of the most surprising in terms of how carnage varied over fairly short distances. This was also the first time we noted what we suspected: misinformation kills.”

Emile Okal, a seismologist and professor of earth and planetary sciences at Northwestern University, conducted approximately 120 interviews with tsunami survivors in 70 different locations around Tutuila and Upolu. He found that most people were educated about tsunamis and knew how to react because of community-based educational programs, not ancestral stories.

“The last significant tsunami in Samoa occurred in 1917 and was very similar in seismology to the Sept. 29 tsunami. Surprisingly, no one I interviewed said they knew of family members being in a similar situation,” Okal observed. “Since the 2004 Indian Ocean tsunami and the 2007 Solomon Islands tsunami, there has been a concerted effort on the part of the local government in American Samoa to post signs and conduct evacuation drills in some Samoan communities. Many villages were completely destroyed, so I am impressed that the death toll was not larger. The bottom line is education worked.”

While Synolakis agreed that the death toll was probably minimized due to educational efforts, he said there is still a lot of progress that can be made. While working in the field on Oct. 7, the team experienced a real tsunami warning and witnessed first-hand the tremendous confusion and disorganization that followed.

“Although there are warning signs along the beaches in American Samoa, there is no information about where the evacuation routes are,” he said. “It’s also just as important to let people know when it’s safe to come back as it is to warn them. We definitely have our work cut out for us.”

The collected field data serves as benchmarking and validation of numerical tsunami models with wide-ranging applications including forecasting, warning and sediment transport. The researchers will present their findings at special sessions at the American Geophysical Union Fall Meeting in San Francisco this December. Brief publications summarizing the immediate results will follow in research journals.

This survey was partially supported by the Pacific Earthquake Research Center (PEER).

Nancy Fullbright | Newswise Science News
Further information:
http://www.gatech.edu

More articles from Earth Sciences:

nachricht NASA eyes Pineapple Express soaking California
24.02.2017 | NASA/Goddard Space Flight Center

nachricht 'Quartz' crystals at the Earth's core power its magnetic field
23.02.2017 | Tokyo Institute of Technology

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>