Coral mining, landscaping and other instances of human development in Sri Lanka helped last December’s devastating tsunami sweep even further inland than it might have, causing intense destruction, scientists said Thursday.
They recommended that officials and developers in areas that might be threatened by tsunamis take note.
“The implications are applicable for any other tsunami,” Harinda Joseph Fernando of Arizona State University said in a statement. “We’d like this report to sound an alarm that governments have to be more careful about enforcing coral poaching and destroying the beaches’ natural defenses.”
The Dec. 26 tsunami killed more than 176,000 people and left about 50,000 missing and hundreds of thousands homeless in several Indian Ocean countries including Indonesia, Sri Lanka, India, Thailand and the Maldives.
It was triggered by a giant earthquake just off the coast of Indonesia’s island of Sumatra — an area vulnerable to more such quakes.
Fernando and colleagues visited Sri Lanka and found the east coast, which was directly hit by the wave of water, had floods of up to 30 feet to 35 feet (10 meters).
Development's role
The west coast was hit more indirectly as the tsunami wrapped around the island, and some areas were affected to a greater extent than others.
“We noted a number of instances where human development likely modified the run-up behavior of the tsunami,” they wrote in their report, published in Friday's issue of the journal Science.
“The Samudra Devi, a passenger train out of Colombo, was derailed and overturned by the tsunami, killing more than 1,000. In the immediate area, substantial coral mining had occurred, related to tourism development,” they added.
There, the tsunami inundation was as deep as 25 feet (7.6 meters). Similar damage was seen in the town of Yala.
“One resort, for the purpose of better scenic views, had removed some of the dune seaward of its hotel. The hotel was destroyed by the tsunami,” wrote the researchers, who included experts at Cornell University, Texas A&M University, the U.S. Geological Survey, Georgia Institute of Technology, University of Washington, the University of Southern California and New Zealand’s National Institute of Water and Atmospheric Research.
Neighboring areas where the dunes were intact were not as badly damaged.
“In essence, by removing some of the natural coastal protection in a localized area, a conduit was created through which the tsunami energy could flow more freely,” the researchers said.
Separate report on Indonesia
In a second report, Jose Borrero of the University of Southern California said the tsunami flooded some parts of Indonesia’s Aceh region with as much as 100 feet (30 meters) of water and pushed the coastline as far as a mile (1.6 kilometers) inland.
The waves washed up hills as high as 80 feet (24 meters) above sea level in some areas and inundated 25 square miles (10 hectares) near Banda Aceh.
Borrero noted that it took considerable time and effort to survey the devastated area.
“In future events, satellites could be directed to image affected regions and guide emergency response, allowing for more focused damage assessment and field measurements,” he suggested in his report.
Experts say pressure is building along the same Sumatran fault line and another quake will come — the only question is when.
On Wednesday, John McCloskey of the University of Ulster said the area under the Mentawai islands west of Sumatra is most at risk of an earthquake with a magnitude of 8 to 8.5 or stronger.
