More on Big Waves

Costas Synolakis writes in the Opinion Journal on warning systems for Tsunamis, and on educating people to run to high ground when they feel tremors and are near the water.

The images from Sri Lanka, India and Thailand that have filled our screens--and the descriptions from survivors--are sadly all too familiar, at least to those of us who have conducted tsunami field surveys. At times, some of us thought that we were revisiting images from Flores in 1992, or East Java in 1994, Irian Jaya in 1996, Papua New Guinea in 1998 and Vanuatu in 1999--to just mention catastrophes in countries with similar landscape and coastal construction.

The response of local residents and tourists, however, was unfamiliar, at least to tsunami field scientists for post-1990s tsunamis. In one report, swimmers felt the current associated with the leading depression wave approaching the beach, yet hesitated about getting out of the water because of the "noise" and the fear that there was an earthquake and they would be safer away from buildings. They had to be told by tourists from Japan--a land where an understanding of tsunamis is now almost hard-wired in the genes--to run to high ground. In another report, vacationers spending the day on Phi Phi were taken back to Phuket one hour after the event started. In many cases tsunami waves persist for several hours, and the transport was nothing less than grossly irresponsible.

Contrast these reactions with what happened in Vanuatu, in 1999. On Pentecost Island, a rather pristine enclave with no electricity or running water, the locals watch television once a week, when a pickup truck with a satellite dish, a VCR and a TV stops by each village. When the International Tsunami Survey Team visited days after the tsunami, they heard that the residents had watched a Unesco video prepared the year before, in the aftermath of the 1998 Papua New Guinea tsunami disaster. When they felt the ground shake during the 1999 earthquake, they ran to a hill nearby. The tsunami swept through, razing the village to the ground. Out of 500 people, only three died, and all three had been unable to run like the others. The tsunami had hit at night.

Which says volumes about the value of education.

The angry questions that hundreds of thousands of family members of victims are asking, especially in Sri Lanka and India, are "what happened?"--and "why did no one warn us before the tsunami hit?" The Pacific Tsunami Warning Center had issued a tsunami bulletin and had concluded that there was no danger for the Pacific nations in its jurisdiction. Why didn't it extend its warning to South and Southeast Asia? It is perhaps clear with hindsight that an Indian Ocean tsunami warning center should have been in place, or that the Indian Ocean nations should have requested coverage from the Pacific Tsunami Warning Center.

Yes.

Clearly, the hazard had been grossly underestimated. To give governments the benefit of the doubt, the last transoceanic tsunami that had hit the region was in 1882, and this was caused by Krakatoa's eruption. Other large earthquakes along the Sumatra trench had not caused major tsunamis, or if they had, they had not been reported as devastating. Floods occur nearly every year, as do storms. Natural hazards that are less frequent tend to be ignored. No nation can be ready for every eventuality--as 9/11 painfully demonstrated--at least before a major disaster that identifies the risk. Without the governments of Indian Ocean nations having identified the risk, they probably did not feel they needed the services of the Pacific Tsunami Warning Center, however free. Even simple and inexpensive mitigation strategies such as public education possibly did not even occur as a possibility. The rapid tourist development of Sri Lanka may also have contributed to the government's inaction toward suggesting that some of the region's most beautiful shorelines may have hidden dangers.

But the occurrence of this massive and destructive tsunami does prove that megatsunamis can occur in the Indian Ocean. The Intergovernmental Oceanographic Commission should continue its efforts to develop a long-term approach to tsunami hazard mitigation through a coordinated program involving assessment, warning guidance, and mitigation aimed at at-risk communities. Improved numerical wave propagation models, new scientific studies to document paleotsunamis, and the deployment of tsunameters will help better monitor tsunami occurrences and develop inundation maps that will guide evacuation plans. As is done among Pacific nations, Indian ocean scientists, disaster managers, policy makers, and local communities need to work together toward the common goal of creating tsunami-resistant communities with access to accurate, timely tsunami warnings. A tsunami warning center needs to be established as soon as practical in the region, and the Pacific Tsunami Warning Center should act as an interim warning center.

Many developing countries do not have the resources and will need substantial assistance. Even among nations in the Pacific rim, only three have comprehensive inundation maps, and none, including the U.S., have probabilistic tsunami flooding maps that reflect the realities of the past 30 years. Unesco's Intergovernmental Oceanographic Commission and the U.S. should help the effort in implementing the U.N.'s global tsunami hazard mitigation plan before the next Asian tsunami disaster strikes.

Please. If we do it right, this disaster can be the "Titanic" tragedy of the 21st Century, encouraging us to at least use our hindsight to accomplish what we wish we'd done from the get-go.

H/T: Dean's World.