Most of us felt a tremor that originated in Jaco, Costa Rica, on August 24, being that it resonated throughout the country. This was the second earthquake of a magnitude of at least 6 in the seismogenic zone since the RSN was formed in 1973. The other was in 2017, with a magnitude of 6.2, approximately 18km southeast of the one that happened this week.
The 6.2 magnitude quake this week was followed by aftershocks up to a magnitude of 3.6. There were dozens of microseisms of under 2 magnitude as well as 19 aftershocks, including six over a magnitude of 3. The National Seismological Network (RSN) received about 1,000 reports.
Based on data from studies of earthquakes in the central Pacific over many years, experts report that there is a high probability of this earthquake being followed by a similar one quite soon. This is known as seismic pairs.
The National Seismological Network agrees and states that there is a 31% probability that an earthquake of at least a 5 magnitude will occur in the following week. There is a 4% chance that the pair will be equal to or greater than the original 6.2 one.
A seismic duo happened in January, in Dominical de Osa and was felt in the Central Valley.
The famous Cóbano earthquake, in 1990, with a magnitude of 7, generated a seismic swarm months later.