CHILE: Asian Tsunami Highlights Past Tragedies, Future Risk

By IPS Correspondents Reprint | | Print |

María Cecilia Espinosa

SANTIAGO, Jan 7 2005 (IPS) - The devastating tsunami that struck Asia and Africa on Dec. 26 was a sobering reminder to Chile of the constant threat it faces as a country “bathed” by the Pacific Ocean, as its national anthem says. And worst of all, it is a threat for which the country is largely unprepared.

The killer waves that struck South and Southeast Asia and Africa, claiming over 150,000 lives, were painfully reminiscent of the tsunami that hit southern Chile in 1960.

Moreover, the recent catastrophe has alerted Chilean experts to the fact that if such a disaster were to strike this South American nation today, the authorities and population would face considerable obstacles in coordinating the efforts needed to ensure that the resulting damage was kept to a minimum.

With an area of 756,252 square kilometres, Chile is the seventh largest country in South America, but because it is essentially a long and extremely narrow strip of land along the western edge of the continent, it is the country with the greatest coastal area in relation to its total size, with over 4,300 kilometres of Pacific shoreline.

The entire country is located over the zone where the Nazca and South American tectonic plates meet, and collisions of the two create the kind of seismic movement that could trigger a tsunami.

As a result, there is considerable potential for Chile to be struck anew by a disaster of this kind, according to Carlos Aranda, head of the Seismological Service at the University of Chile.

On May 22, 1960, the largest earthquake ever recorded – measuring 9.5 on the Richter scale – took place between the southern Chilean provinces of Concepción and Chiloé.

The energy released by the quake was thousands of times greater than the atomic bombs dropped by the United States on Hiroshima and Nagasaki, Japan, in 1945, and a third of Chile’s population at the time (just over two million in total) was affected.

Waves almost 20 metres high lashed the coastline, flooding the city of Valdivia, the most severely hit. Close to 45 percent of the city’s buildings were destroyed, and total damages were estimated at one billion dollars, while roughly 6,000 lives were lost.

According to the University of Chile Seismological Service, the earthquake that triggered the recent Asian tsunami and the one that shook Chile in 1960 both occurred in subduction zones, where one tectonic plate is forced down beneath another. The Valdivia earthquake, however, released at least eight times more energy.

Moreover, Chile has a long history of previous quakes, including two in Valparaiso in 1730 and 1906, one in Concepción in 1835, two in Arica in 1868 and 1879, and one in Taltal-Coquimbo in 1922. All of them caused tsunamis.

People living near the ocean are of course particularly vulnerable, but given Chile’s long, narrow shape and extensive coastline, this means that a large proportion of its population is at risk.

The Chilean Army Hydrographic and Oceanographic Service (SHOA) has conducted studies which indicate that 28 cities could suffer significant devastation in the event of a tsunami.

The SHOA is connected to the Pacific Tsunami Warning System, based in Hawaii, which comprises dozens of censors and seismographs throughout the Pacific, interlinked by satellite.

The system issues an alert when an earthquake occurs, providing the location and allowing time to determine if it is likely to cause a tsunami, and how powerful that tsunami will be.

If the earthquake takes place in Japan, the waves would take between 22 and 25 hours to reach the Chilean coast, but if it occurs closer to home, the time to prepare is greatly reduced.

“If a quake occurs nearby, Chile will not have hours to prepare, as was the case in Southeast Asia, but merely a matter of minutes,” said Alberto Maturana, director of the National Emergency Office of the Ministry of the Interior (ONEMI).

“No city in the world is prepared for a catastrophe, even if it strikes in countries like the United States or Japan. When an event reaches catastrophic proportions, it overwhelms all attempts at preparation,” Maturana told IPS.

Nevertheless, he added, unlike the Asian and African countries hit by the Dec. 26 tsunami, Chile has developed a programme to educate the population about the risks and the measures that need to be adopted if disaster strikes.

Initiated three years ago, the programme is carried out in conjunction with the SHOA and other specialised agencies, and encompasses 92 coastal municipalities in Chile.

Some of them, Maturana noted, “have achieved certain objectives before the others, such as the planning and marking of evacuation routes in Arica and Antofagasta.”

Others have at least made progress in raising public awareness and educating communities on the actions they should take in the event of a tsunami.

According to Aranda, however, although all of the information and other elements needed for the development of the disaster prevention plans promoted by the authorities exist, they are not being properly carried out.

“I understand that only 15 percent of the local authorities responsible for emergency planning have attended the courses offered by ONEMI, which should be a priority, given the current circumstances,” he said.

Maturana agrees that the role of local governments is fundamental. “A real commitment is needed on the part of mayors and other municipal authorities to adequately mobilise the instruments within direct reach of their communities.”

In accordance with tsunami contingency plans, residents of and visitors to coastal communities should seek refuge in areas at least 20 metres above sea level when a warning is sounded, taking with them only essential items like flashlights, radios, batteries and matches.

Once the tsunami has passed, they should not consume food or water that has come in contact with the waves, in order to prevent epidemics.

“People should act automatically when they detect abnormal sea conditions,” said Maturana. “If they feel the movement triggered by a nearby tremor or earthquake, they should immediately evacuate with their families to higher land, without waiting for a siren or someone to inform them. The quake is a warning sign in itself, and the same is true if the tide suddenly begins to recede,” he said.

“The education and integration of the community, including drills and participation in the formulation of plans and programmes, should come first and foremost, with outside warnings serving as a complement,” he added.

The most recent figures available indicate that barely 100,000 insurance policy holders, mostly businesses, have acquired additional coverage for the effects of earthquakes and tsunamis, although a growing number of banks are demanding earthquake insurance as a prerequisite for taking out a home mortgage.

Specialists agree that Chile is not free from the risk of a tsunami as powerful as the one that hit Asia and Africa in late December.

The University of Chile has set up 80 seismological stations connected to the ONEMI regional offices, equipped to evaluate the threat posed by eventual tremors or quakes. The problem, however, is that the communications system these stations depend upon would almost certainly be knocked out of service by a high-intensity earthquake.

“We haven’t been put to the test, so the question remains as to how our network would operate. We know that the seismographs would work, but we also know that the communications systems connecting many of them would not work,” said Aranda.