Sumatra Plus Four

The great earthquake and tsunami of Sumatra was four years ago today. The earthquake, approximately magnitude 9.2, was the second-greatest ever measured on a seismograph. (Read more about the earthquake.) It killed tens of thousands of people; but even so it was merely a regional tragedy. The tsunami spread death throughout the Indian Ocean and its shores, from Indonesia to South Africa, and made it a truly global catastrophe.

One widely believed lesson from the tsunami was that coastal forests, particularly mangrove swamps, are effective in blocking and damping tsunamis. Anyone who loves wildlands would be eager to believe this, adding it to the long list of reasons for preserving coastal greenbelts. But a team of researchers has found that it appears not to be true. This photopair accompanies the press release from Australia's ARC Centre of Excellence for Coral Reef Studies, showing a Sumatran coast armored by high sand dunes and thick forest. The tsunami wiped it all flat. Perhaps mangroves work for smaller tsunamis. The research team calls for a more thorough study.

The same spot, 1986 and 2005 — Photos courtesy www.coralcoe.org.au