The 6.2 magnitude earthquake that recently devastated the northeastern periphery of the metropolitan area, killing up to 30 people, brought to mind a troubling possibility: Had a similar quake occurred in the Central Valley, the death and destruction would have been much greater, according to geologists, engineers and even political leaders.
“If (the earthquake) had been in an important city, in an urban area, we wouldn’t be talking about a few victims but rather hundreds, if not thousands,” President Oscar Arias said.
More than half the country’s population, hospital beds and grade school students are in the greater metropolitan area, a 1,778-square-kilometer area that stretches roughly from Cartago in the east to Alajuela in the west, and from Moravia in the north to Aserrí in the south.
“A high-intensity earthquake here would be a real disaster,” said Andres Calvo, a national program officer for the Pan-American Health Organization. “We have a long way to go before we are able to withstand a 6.2 earthquake here.”
The last major quake to hit the Central Valley occurred in 1910 in Cartago, the old colonial capital east of San José. The quake virtually destroyed the city, killed up to 1,000 people and injured thousands.
Some scientists say that could happen again. Of Costa Rica’s 150 potentially active faults, about a third are located in the greater metropolitan area, according to Guillermo Alvarado at the Costa Rican Electricity Institute (ICE).
One of the most active faults runs through southern San José, near the towns of Alajuelita, Aserrí, Desamparados and Higuito, said Wilfredo Rojas, a geologist at the University of Costa Rica (UCR).
“When it ruptures and releases energy, it’s going to cause a lot of damage,” he said. “It could happen in decades, or it could happen in a few years.”
A strong quake in the Central Valley would be more devastating today than in 1910 because population density is much higher, said Walter Montero, a UCR geologist.
To Lorena Romero, who has worked on emergency preparedness in the San José municipality for a decade, the Central Valley is not ready for such a quake.
“It’s a question that worries us all: What would happen if there were a disaster, like an earthquake, in the metropolitan area? The first response is that we are not prepared,” she said.
People in poorly built houses would suffer the most. Municipalities can legally give permits only to buildings that follow a strict seismic code. But about 30 percent of buildings in the greater metropolitan area do not comply with the code, said Olman Vargas, director of the Federated Association of Architects and Engineers. Some of these buildings were constructed before the code was first drafted in 1974. In other cases, builders did not have a permit, or municipalities granted permits despite flawed floor plans.
Poor construction would cause about 10 percent of the houses in the metropolitan area to collapse entirely if an earthquake occurred nearby, according to a 2003 study by Luis Salas, who now teaches at the UCR.
Over 500 years, he found, earthquakes in the area can be expected to kill 0.1 percent of the population – or 1,200 people today.
The Central Valley is relatively flat, leaving most areas less vulnerable to the landslides that decimated neighborhoods near Poás Volcano during the Jan. 8 quake. Still, landslides could bury houses and people in the more mountainous towns of Escazú, Desamparados and Aserrí in the western and southern metropolitan area, said Alvaro Climent at ICE.
A quake could be particularly devastating for squatters, who tend to live in makeshift huts in high-risk areas, said Franklin Solano at the Foundation for Housing Promotion.
Of the 397 squatter communities in Costa Rica, more than half are located in the greater metropolitan area, he said.
In a 2002 UCR study, graduate student Henry Fallas studied 32 high schools, each with more than 500 students, in the metropolitan area. He found that repeats of the 1888 Fraijanes and 1910 Cartago earthquakes would produce minimal damage to the schools.
The 1924 Orotina earthquake would be a different story. If that 7.0 magnitude temblor occurred today, more than half of the schools would sustain “broad damage” and 40 percent would sustain “moderate damage.”
Schools would be in even greater trouble if an earthquake occurred along the southern San José fault that UCR geologists have identified as highly active. A 6.3 magnitude there would completely destroy more than half of the high schools studied, while causing “broad damage” to 34 percent, Fallas wrote.
Fallas found that the Colegio Superior de Senoritas, a 120 year-old school with about 1,200 students in downtown San José, was in critical condition and the most vulnerable of the 32 schools studied.
Now, seven years after Fallas published his study, the Education Ministry is hiring a construction firm to “totally restore” the school and bring it into compliance with the seismic code, said Carlos Villalobos, head of the ministry’s infrastructure department.
Highways, Bridges Would Collapse
Important highways and bridges in the greater metropolitan area could also collapse during a quake, disrupting the country’s economy, according to a 2006 study by Guillermo Santana at the UCR.
A repeat of the 1910 Cartago earthquake “would be completely disastrous for the province of Cartago,” Santana found. Eight roads would suffer “broad damage,” and the Inter-American Highway would become unusable.
A strong earthquake in southern San José would also “seriously affect important roads,” Santana wrote. Damage to Route 219 would interrupt the flow of produce from farms near Irazú Volcano.
The same study looked at 98 bridges in the greater metropolitan area and found that more than half would either collapse entirely or sustain broad damage during a strong quake in southern San José.
“The capital (San José) and Cartago would be inaccessible,” Santana wrote. “Rebuilding these areas would be very difficult. The country could experience a collapse similar to what occurred in Managua, Nicaragua, in 1972,” when a 6.2 quake crippled the city.
Mario Loría, deputy director of the bridges department at the Public Works and Transport Ministry, said he did not know whether any bridges in the metropolitan area had been repaired or revamped since Santana drafted the study.
“In Costa Rica, there is no culture of maintaining bridges,” he acknowledged. “We have bridges that have surpassed their ideal life span.”
Some hospital buildings also require quake-proofing. Of the seven national hospitals in the metropolitan area, only three – Hospital Mexico, the Children’s Hospital, and parts of San Juan de Dios – have been renovated to withstand an earthquake, said Jorge Granados, director of architecture and engineering at the national health care system, known as the Caja.
The Caja does not know whether most hospitals and clinics in the area can survive a quake because engineers have not yet conducted seismic studies, Granados said.
San Juan de Dios, built in 1845, offers an alarming example of foot-dragging by authorities faced with potential danger. A November 2006 study showed that a quake would cause the rehabilitation building to collapse, trapping some 50 patients, many of them in wheelchairs or on crutches.
Still, the building was not evacuated until nearly a year later, in October 2007, said Luis Orias, who then worked as a consultant at the hospital and gave the evacuation order.
“It was a death trap,” he said. “We thought, ‘How are the rest of the buildings in terms of safety?’”
While most hospital buildings likely would not collapse during a quake, they would sustain serious damage, according to Miguel Cruz, an engineer who has extensively studied the nation’s hospitals.
Hospitals in the metropolitan area would lose up to 30 percent of their capacity during a quake because of damage to ceilings, windows, doors, electric systems and machinery, Cruz said. To attend quake victims, health authorities would have to set up tents or look for space in hospitals outside the metropolitan area, he added.
Each hospital has drafted an “emergency plan” that tells staff what to do during a disaster. But some of these plans are not communicated to the staff, while others leave out protocols for some wings, said Maurenth Alfaro, who coordinates the Caja’s emergency preparedness program for the metropolitan area.
“Probably no plan follows all the requirements,” she said.
In addition to damaging buildings, a quake would generate panic. Shoppers could be trampled as they rush to escape from malls, said Douglas Salgado of the National Emergency Commission. Spooked drivers could cause accidents, he added.
“There would be enormous chaos,” said Calvo of the Pan-American Health Organization. “Panic alone could cause many deaths or injuries.”
At a local level , committees formed by the National Emergency Commission coordinate disaster preparedness and relief. San José’s committee includes members from about 10 government institutions, including the Education Ministry, the Caja and the Health Ministry.
But Lorena Romero, the committee’s deputy coordinator, said members have trouble procuring funds from their institutions for local projects.
“Preparing for disasters is not a priority for (government) institutions,” she said.
The same could be said for homeowners or business owners. In the weeks following the Cinchona quake, engineer Alvaro Poveda received a flurry of requests for seismic studies.
But he expects the demand to die down as memories of the quake fade.
“We forget our errors,” he said. “But this is a highly seismic country. This will happen again.”