Earth Institute News

posted 05/12/05

Fellows See What Worked, and What Didn't

April 29, 2005
Matara, Sri Lanka

By Guillermo Franco, Cristina Rumbaitis del Rio, Bijan Khazai and J. Carter Ingram

Building Foundations Did Not Support Houses
The tsunami easily devastated structures because their foundations did not support the houses, and because the load-carrying brick walls rested on footings grounded on sand. Buildings with two or more stories that were built with reinforced concrete — typical of wealthier inhabitants — resisted the tsunami much better, sustaining little to no damage.

Revising Expectations
From NGOs and news reports, we expected to see less structural damage where there were mangroves along the coast. It turns out that dense areas of mangroves are very rare in Sri Lanka, unlike other areas in the Indian Ocean basin, because very few places have the alluvial soil and tidal regime necessary to sustain them.

Resilience of Coastal Trees
What is very striking is that some of the coastal trees are largely intact, particularly coconut trees. These trees, with their long slender stems, woody and extensive root mats, and enlarged trunks, seemed to be very resilient to the force of the incoming wave. Interestingly, we have seen that the factors that contribute to tree resilience are similar to those that influence the resilience of buildings: foundation, geometry and height.

Sand Dunes Provide Protection
Sand dunes appear to have provided the greatest protection from the wave’s forces. Along the coast, we noticed in places where intact sand dunes were higher than about 10 meters, little (if any) damage occurred behind them.

For example, in Yala National Park, sand dunes played a crucial role in protecting people from the tsunami. The Yala Safari hotel, unprotected by sand dunes and completely exposed to the ocean, experienced massive damage; 49 people at the hotel died when the tsunami hit.

In comparison, the Yala Village hotel, located about 500 meters away, was protected by an extensive dune system and experienced little to no damage, despite having similar structures as the Yala Village hotel.

Starting Over
In addition to investigating areas of impact, we also visited several relocation camps where tsunami survivors have been living since late December.

Oceans of blue and white tents and temporary wooden huts are ubiquitous all along the coast.

We visited with a fisherman and his family living on the grounds of a Buddhist temple. Even though the living conditions of his family are dire, they are among the more fortunate. The fisherman had already acquired a boat and motor so he would be ready to go out to sea at the start of the next fishing season.

Later in our trip, we met with a group of fishermen who invited us to eat the fish they had caught, despite the fact that they had made no profit on the day’s catch. It has been inspiring for us to see people who have gone through so much hardship continue to smile. We are amazed by their generosity and kind spirit.