San José, Costa Rica, since 1956

The ‘Big One’ finally hits Nicoya Peninsula

By Vanessa I. Garnica and Hannah J. Ryan  |  The Tico Times Staff

“This is the quake we were waiting for,” said Leopold Linkimer, seismologist at Costa Rica’s National Seismological Network, following a powerful magnitude-7.6 earthquake that rattled the country Wednesday morning. “Regardless, we have to be ready for any contingency because nature can surprise us.”

The earthquake was registered 8 kilometers (5 miles) west of Samara in the Nicoya Peninsula, in the northwestern province of Guanacaste. After the quake, which damaged several buildings in the province, shaken residents wondered, was this the big one that experts had predicted would strike the peninsula?

Scientists in Costa Rica have been contemplating the possibility of a big quake in the Nicoya region for more than two decades. The last time an earthquake of a similar magnitude was registered in the area was in 1950. On average about 18 small tremors are registered daily in Costa Rica, Linkimer said.

Following the quake, emergency officials gathered at National Emergency Commission (CNE) headquarters in the western San José district of Pavas to discuss initial damage reports.

“We are not declaring a state of emergency at the moment,” said Vanessa Rosales, CNE president. “We have begun to receive damage reports taking place around the country. Overall, we feel at ease at this point, even though it was a significant quake.”

Wednesday’s quake is considered the second biggest in the nation’s history, behind a 1991 earthquake measuring magnitude-7.7. That quake, centered in Limón province along the Caribbean coast, killed 75 people and injured more than 600.

Linkimer said the official magnitude of the quake could be adjusted in coming days, pending further studies. He said that several aftershocks also are expected.

Earthquakes can cause landslides in areas near the epicenter, but not necessarily volcanic activity, Linkimer said. However, volcanic activity was reported at the Irazú and Rincón de la Vieja volcanoes in 1991.

In some cases, volcanic activity could be registered at the exact moment an earthquake hits, Linkimer explained, although it could take weeks for activity to resurface as a result of a quake of such magnitude.

The cause of Wednesday’s quake, and others of its kind in Costa Rica, is attributed to a process called subduction, where tectonic plates located in the Earth’s outer layer constantly move on top and under each other, causing the ground to move in the form of a tremor.

Seismologists agree that all regions in Costa Rica are considered very active and apt for an earthquake at any given time. However, Linkimer said a big earthquake had been expected in the Nicoya Peninsula since the early 1990s.

“There are certain [scientific] models that describe that some earthquakes will occur with regular occurrence,” he said.

For more coverage of the Nicoya Peninsula earthquake, see Friday’s print edition of The Tico Times.

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