Since the evening of Tuesday, January 9, an earthquake swarm has been affecting the area of Guanacaste, in particular to the southeast of the Tenorio Volcano.

The first mild earthquake was felt on Tuesday the 9th at 8:56 p.m. (right after the earthquake that rocked the coast of Honduras), several were registered on Wednesday and Thursday. The National Seismology Network had registered a total of 23 movements  for a total of 42 since Tuesday. The magnitude of the movements have been between 2.2 and 5.3, and were felt in the areas of Bagaces, Tilaran, Abangares and Santa Cruz in Guanacaste, along with certain areas of Alajuela and Puntarenas.

“Another notable effect of these earthquakes from January 11, was the change of coloration in the water of some blue rivers, as is the case of El Roble, located in the slopes of the Tenorio Volcano. These changes are normal and can be a result of disturbances of the aquifers during important earthquakes or material that has fell in the rivers as a result of landslides. This phenomenon had been reported before during the seismic activity of 2002 and 2016 in the same region”, states the information provided by the National Seismology Network.

Rio Celeste or Light-Blue River is a famous tourism attraction in Costa Rica, the river gets its baby blue coloration from a natural chemical reaction that occurs between minerals in this volcano-rich region and the point of union of two rivers, Buena Vista and El Roble, each with different chemical characteristics.

The National Emergency Commission temporarily closed the Tenorio Volcano National Park, as a preventive measure while they finish evaluating the conditions of the trails and areas commonly visited by tourists and ensuring the safety of the same. “After our first evaluation it was determined that some landslides took place and caused material to fall into the river changing the coloration of the same, for this reason the recommendation was to close the National Park temporarily”, explained the National Emergency Commission.