Earthquakes are quite common in Costa Rica. Every day it trembles. This is proven by the 200,000 earthquakes registered since 1973; that is, Costa Rica shakes and rolls on average 12 times a day.
The strongest was the Limón earthquake of April 22, 1991, with a magnitude of 7.7 degrees, killing 27 and damaging the Limón rail line so severely that repairs have never been attempted.
The deadliest in Costa Rica history struck north of the Central Valley, on January 8, 2009 and claimed 34 lives in and around the town Cinchona.
Major earthquakes strike Costa Rica about once a decade but no tourist has ever been killed or seriously injured.
Faced with this inescapable reality, key questions arise such as, what are the most prone areas? How strong should buildings, bridges or any other construction in the country be? How much acceleration or jolt could they be subjected in case of an earthquake?
Costa Rican scientists, in conjunction with engineers from the University of Costa Rica (UCR), will seek answers with seismic hazard studies that, for the first time, will be carried out without relying on international colleagues.
“The study is very important to know the ratio between small and large earthquakes because that gives us an idea about the largest earthquake that can occur in any specific area in the next 50 years,” explained Lepold Linkimer, researcher of the Red Sismológica Nacional (RSN) – National Seismological Network.
With the studies, he said, they will prepare seismic hazard maps of the places where earthquakes are expected with higher intensities in a certain period of time.
Currently, the RSN has about 160 stations throughout the country, which allows recording and describing how, when and where it trembles, with the idea of estimating how big earthquakes can be in our country.
“At the moment it is the magnitude of 7.7, but it could be more,” warned the seismologist.
The information is transferred to the Comisión Nacional de Emergencias (CNE) – National Emergency Commission -, municipalities, the Colegio de Ingenieros y de Arquitectos (CFIA) – College of Engineers and Architects, among other institutions, to draw up regulatory plans. In this way, the risk will be another variable to determine land use.
The Seismic Code establishes requirements and constructive rules to ensure that the structures that are erected support the tremors.
Historically, studies of danger or seismic hazard were made by researchers from international universities, with the help of Costa Rican professionals.
“They came, they prepared the studies and they left us the results, but they took (with them) the calculation data and all the knowledge,” said Diego Hidalgo, coordinator of the UCR’s Laboratorio de Ingeniería Sísmica (LIS) – Seismic Engineering Laboratory.
As a result of this, there were people abroad who knew better than the national geologists the activity of the Costa Rican terrestrial crust.
Now that has changed, because with the contribution of funds to the RSN and the LIS, a product of the Ley Nacional de Emergencias y Prevención del Riesgo – National Law of Emergencies and Risk Prevention – there are instruments that provide a complete view of the seismicity, which allows us to do those studies here.