Q COSTA RICA — Costa Rican authorities continue to monitor the seismic activity triggered by the powerful 7.7-magnitude earthquake that struck Panama last Friday, October 9.
The Observatorio Vulcanológico y Sismológico de Costa Rica (Ovsicori-UNA)—Volcanological and Seismological Observatory of Costa Rica—has recorded over 300 aftershocks, some of which were felt in communities near the border between the two countries.
According to a report released by the Oviscori, its network of seismological stations had recorded more than 300 secondary tremors, 46 of which reached magnitudes greater than 4.5.
This figure reflects the intense ongoing activity in the area where the earthquake originated; the quake’s epicenter was located on the Azuero Peninsula in Panama, and it caused prolonged shaking across several Costa Rican provinces.
Although the aftershocks originate primarily within Panamanian territory, monitoring equipment installed in Costa Rica has successfully detected a significant number of these events, particularly those of higher magnitude.
Specialists explained that some of the secondary tremors were felt again by residents in the south of the country due to their proximity to the region where the tectonic activity persists.
“It is very likely that some were felt in Costa Rican communities near the border with Panama,” explained Wálter Jiménez, a seismologist at Ovsicori.
Aftershocks subside, but seismic activity continues
Despite the high number of tremors, specialists noted that the activity recorded over the weekend aligns with the expected pattern following a major earthquake.
Ovsicori identified a downward trend in the frequency and magnitude of aftershocks—a phenomenon typically observed as time passes following the main event.
According to technical analysis, the seismic sequence is following a decaying exponential curve, meaning that secondary tremors tend to occur less frequently as the fault zone’s readjustment process progresses.
The Ovsicori described this behavior as “normal and to be expected in events of this magnitude.”
However, experts clarified that a gradual decline in activity does not mean the aftershocks have ended, nor does it rule out the possibility of further tremors being felt within Costa Rican territory.
How long might the tremors in Costa Rica continue?
Specialists from the Red Sismológica Nacional (RSN) de la Universidad de Costa Rica (UCR)—National Seismological Network (RSN) at the University of Costa Rica (UCR)—addressed the possibility of further seismic activity occurring over the coming weeks.
Seismologist Leopold Linkimer explained that, following a major earthquake, aftershock activity can persist for days, weeks, or even months, although it typically tends to gradually subside.
The expert also noted that the location of the epicenter—outside Costa Rican territory—poses a challenge for national monitoring systems.
This is because seismological stations are distributed primarily within Costa Rica, whereas most aftershocks originate at a considerable distance from these instruments.
Consequently, specialists can more easily locate stronger events, while smaller tremors are more difficult to identify with precision.
The Ovsicori and the RSN emphasized that it is impossible to predict with precision when a new aftershock will occur or what its magnitude will be.
However, the behavior observed so far indicates a progressive reduction in the most intense activity.