One of the strongest earthquakes ever recorded struck the central coast of Chile early Saturday morning, February 27. The U.S. Geological Survey (USGS) measured the magnitude at 8.8 with severe “shaking intensity” extending nearly 500 kms (app. 300 miles) from the epicenter on the coast just above the city of Concepcion. More than 700 people are reported to have died, but the death toll is expected to rise, as rescue workers reach the worst affected areas.
Tsunami warnings were issued across the Pacific Ocean from the coast of California, to the Hawaiian Islands, Australia and Japan. Although some waves were recorded, notably in Japan and New Zealand, little damage has been reported, and as of Sunday morning most alerts had been lifted.
Catastrophe modeling firms EQECAT and AIR Worldwide, have both issued bulletins analyzing the damages caused by the quake. EQECAT noted: “This magnitude 8.8 event has caused significant ground motions throughout central Chile and severely impacted the capital Santiago and the immediate coastal area of Valparaíso and Viña del Mar. Strong ground motions extend from Valparaíso in the north to Temuco in the south and extend to the inland valley areas including Santiago. This earthquake has occurred about 200 km north of the 1960 event, the largest event measured on the globe in the last 200 years, which is now estimated as a Magnitude 9.5 event.”
AIR described the shock as a “great earthquake,” originally estimated at “8.3 and later revised to Mw8.8 by the USGS.” AIR explained that the “quake occurred at the boundary between the Nazca and South American plates about 325 kms [app 200 miles] southwest of the capital Santiago (est. pop. 5.3 million). Focal depth has been estimated at 35 kms [app21.8 miles below the earth’s surface]. At least four aftershocks of Mw6 or higher have already occurred, the largest at Mw6.9.”
As strong as the quake was, its center was south of Chile’s most populated cities. Reports of the extent of the damage are still being compiled, but AIR said the quake was “likely to have caused considerable damage in towns closer to the epicenter.” Later reports confirmed that widespread devastation had occurred in Concepción (est. pop. 300,000), Chillan (est. pop. 170,000) and other towns near the quake’s epicenter.
The extent of the damage in the region around Concepcion and elsewhere has hampered rescue efforts, as roads, bridges and rail lines have been severely affected. There is no electric power, and little running water in most of the area. Army troops are working with local police to keep order in the stricken region and to assist rescue efforts.
Even though the more northerly population centers were largely spared the worst, they will account for a high proportion of the losses. “Damages in the state of Santiago are expected to exceed 50 percent of the total damages,” EQECAT said. “Santiago is the largest commercial and population center in Chile with almost 5 million people in the city experiencing very strong ground motions from this event. Immediately to the west with a smaller population and higher ground motions, damage in the state of Valparaíso is expected to be about 25 percent of the total damage from this event.”
EQECAT estimated the “total value of economic damage to be in the range of $15 to $30 billion.” The bulletin explained that, assuming a conversion rate of 520 Chilean Pesos to the dollar, would put the losses “in a range of 8 trillion to 16 trillion” in local currency, which is about “10 percent to 15 percent of Chile’s real GDP.”
However, EQECAT pointed out that, while this is certainly a “major disaster, Chile’s widespread adoption and enforcement of modern, seismic-resistant building practices has mitigated the potential for devastation. While some buildings will have collapsed or suffered irreparable damage, EQECAT expects these to be a minority of the overall building stock.”
As strong as the quake was, the damages and loss of life could have been much worse. But, due mainly to the fact that Chile has had a great deal of prior experience with earthquakes, the country has, unlike Haiti, been able to take remedial action.
Dr. Mehrdad Mahdyiar, director of earthquake hazard at AIR Worldwide, noted that in addition to the “largest ever recorded earthquake,” the quake which struck on Saturday “is Chile’s largest since the Mw8.0 1985 Valaparasio/Santiago earthquake, which killed nearly 200 people and destroyed 140,000 homes.” The damages from that event reinforced Chile’s commitment to strengthen and enforce stricter building codes. In fact, “Chile has a long history of building code evolution, beginning in 1928,” Mahdyiar explained.”
The codes have been frequently revised, most recently in 1993. “As a result, Chile has more stringent building codes than its neighbors, superior construction quality, and possibly the most highly engineered building inventory in Latin America. This will undoubtedly help mitigate the damage,” he added.
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