Three earthquakes that registered better than 5.0 magnitude rattled the northern zone Tuesday afternoon. All took place within 40 minutes. Then a 4.1 magnitude aftershock hit less than an hour later.
The national emergency commission said that there were no injuries, although some persons were treated for panic attacks.
The first quake, the largest at 5.6 magnitude, took place at 2:11 p.m. The second was at 2:17 p.m., and the third was at 2:51 p.m., said the U.S. Geological Survey. Both were 5.1 magnitude, although the Observatorio Vulcanológico y Sismológico de Costa Rica here put the magnitude at 4.8. The observatory also said the first quake was just 5.3 magnitude.
All were between 14 and 20 kilometers southwest of Upala. That’s about 9 to 12.5 miles.
The observatory attributed the quakes to a local fault. There are several in the area.
The emergency commission said that objects fell in San Juan de Guatuso, Aguas Claras, Las Armenias, San Isidro and Bijagua de Upala. In Guacalito de Las Armenias two homes suffered damage, mainly cracks in the wall.
A bridge over the Río Negro was reported to have been damaged in Aguas Claras.
Experts from the Comisión Nacional de Prevención de Riesgos y Atención de Emergencias were planning to fly over the area early today. They are seeking evidence of slides or other damage. There was a report of a slide that blocked the upper portion of the Rio Guacalito, and officials want to make sure that a dangerous temporary dam is not in pace.
If such a dirt dam gives way after significant amounts of water have backed up, there could be flooding below.
The strongest quake was relatively shallow at 10 kilometers or about 6 miles, according to an estimate by the observatory.