Two moderately strong earthquakes hit Costa Rica's Southern Zone on Wednesday. The first, a magnitude 5.7 quake, struck at 11:24 a.m. near the mouth of the Golfo Dulce, and the second, magnitude 5.9, a few kilometers farther north in the gulf, according to preliminary reports from the U.S. Geological Survey.

Local instruments, on the other hand, registered different numbers. The National Seismological Network recorded a magnitude 5.5 for the first quake, while the Volcanological and Seismological Observatory of Costa Rica (OVSICORI) issued reports with magnitude 6.3. For the second, the two institutions registered magnitudes of 5.7 and 5.8, respectively.

Although the area sits just off a major fault line, Wednesday's quakes were both shallow – less than 30 km in depth – and, said USGS geophysicist Bruce Presgrave, the initial interpretation is that they are the results of movement along local fault lines.

“The tremor was a bit strong, but we didn't have any damage,” said Isai Venegas, assistant manager at the Danta Corcovado Lodge, located near Golfo Dulce. Venegas, an Osa Peninsula native, added the quake was the second strongest he has ever experienced.

The Red Cross and the National Emergency Commission (CNE) reported no injuries and only very limited structural damages. Nature Air representatives also in Puerto Jiménez said the airport was unaffected.

On Jan. 8, a magnitude 6.1 earthquake hit Costa Rican territory, centered right by the Poás Volcano, a couple dozen kilometers northwest of San José. Officially, 23 people died in that quake, with another seven whose bodies were never located and are now presumed dead.

Costa Rica sits over a conflux of various tectonic plates, what seismologists qualify as a “highly seismic” territory.

Tico Times reporter Vanessa I. Garnica contributed reporting.