"It was a sudden release of energy from a portion of the active fault." With that definition, Néstor Luque, director of the Institute of Geosciences of Panama, explained the origin of the earthquake of magnitude between 7.5 and 7.7 that on Friday, October 9, forced the evacuation of homes and buildings, left at least two people injured, and cut off Tonosí by land, the town located near the epicenter.
The quake occurred at a depth of 10 kilometers and triggered a sequence that did not subside after the initial shock. The Institute of Geosciences of Panama counted 107 aftershocks in different areas of the country. According to Luque, these tremors are concentrated in the Azuero-Soná Fault System, the geological structure that the main event crossed.
The IGC recorded 107 aftershocks after the earthquake in Panama
The focus of the subsequent tremors was located in the Azuero-Soná Fault System, an active geological structure that crosses the area where the main movement originated. For Luque, the sequence of tremors is not an isolated episode: it confirms that a section of that fault suddenly discharged the accumulated pressure.
According to the director of the IGC, the system had accumulated stress over a prolonged period until it reached its elastic limit and fractured. The aftershocks now respond to the readjustment of the tectonic blocks as the release of the accumulated energy continues.
The value assigned to the earthquake changed as the seismic net…
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A car covered in debris from houses damaged by the impact of the earthquake in Villa de los Santos, Panama. (AP/Aris Mariota) "It was a sudden release of energy from a portion of the active fault." With that definition, Néstor Luque, director of the Institute of Geosciences of Panama, explained the origin of the magnitude 7.5 to 7.7 earthquake that on Friday, October 9, forced the evacuation of houses and buildings, left at least two people injured, and cut off Tonosí by land, the town located near the epicenter. The quake occurred at a depth of 10 kilometers and triggered a sequence that did not subside after the initial shaking. The Institute of Geosciences of Panama counted 107 aftershocks in different areas of the country. According to Luque, these tremors are concentrated in the Azuero-Soná Fault System, the geological structure that the main event crossed. The focus of the subsequent tremors was located in the Azuero-Soná Fault System, an active geological structure that crosses the area where the main movement originated. For Luque, the sequence of tremors is not an isolated episode: it confirms that a section of that fault suddenly released the accumulated pressure. According to the IGC director's explanation, the system had accumulated stress over a prolonged period until reaching its elastic limit and fracturing. The aftershocks now respond to the readjustment of the tectonic blocks as the release of accumulated energy continues. The Institute of Geosciences counted more than one hundred aftershocks concentrated in the Azuero-Soná Fault System. (MARTIN BERNETTI / AFP) The value assigned to the earthquake changed as the seismic network incorporated new records. Luque explained that the initial calculation is performed automatically with a small number of stations and then readjusted when the information from the entire national network is analyzed. With that reevaluation, the Institute of Geosciences of Panama (IGC) raised its estimate from 7.2 to 7.5; the United States Geological Survey (USGS) went from 7.6 to 7.7. Luque explained that the shallow depth of the quake —less than 10 kilometers— was another of the factors that intensified the shaking in areas near the epicenter. He also specified that the aftershocks are of lower magnitude than the main event and are part of the readjustment of the Earth's crust after the release of energy. "All these aftershocks occurred in the area where the Azuero-Soná Fault System is located, which effectively corroborates that the main event was a sudden release of energy from a portion of the active fault," he said in statements to the television network TVN. The first ones reached magnitudes of 6.2 and 6.5, before the sequence dropped to values between 5 and 4, and then to ranges of 3 and 2. The IGC director also warned that some notifications from the system may correspond to technical reviews of events already recorded and not necessarily to new tremors. The difference responds to the data processed by each agency and to the methodologies of their station networks. Beyond that variation, the two measurements agree on one point: the quake was among those with the greatest impact recorded in Panama. The area near the epicenter was left without road connection. The authorities completely closed land access to Tonosí and arranged for entry to be made only by air, while technical teams review the condition of the roads and proceed with damage assessment. The differences in magnitude measurement between the IGC and the USGS stem from the use of different networks and methodologies. (REUTERS/Enea Lebrun) The first official survey drew a map of damage that reached water treatment plants, churches, hotels, businesses, public buildings, and roads. The impact on the water system generates additional concern: almost all the treatment plants in the country showed damage, although the Government has not yet specified whether there will be cuts or in which areas. In Penonomé, capital of the province of Coclé, the earthquake left damage to buildings and nearby roads. One of the towers of the Cathedral of San Juan Bautista collapsed while priests and the local bishop, Edgardo Cedeño, were meeting inside the temple. Cedeño told the EFE agency that the collapse occurred while the group was still inside the building. No deaths were reported from the collapse of the religious structure. In Veraguas, the earthquake left two people injured and a rescue operation among the rubble of a collapsed church. Arturo González, regional director of the National Civil Protection System (Sinaproc), confirmed to local television that a person was found alive after being trapped under the structure. Emergency teams rescued a person trapped in the rubble of a church in the province of Veraguas. (REUTERS/Enea Lebrun) With the aftershocks still active, emergency teams continued inspecting homes, buildings, and areas considered at risk. Attention focused on constructions with cracks, detachments, or visible signs of structural damage, given the possibility of new movements. As of the last official report, the authorities had not reported any deaths. The assessment continued in the affected provinces, with priority given to communities that are hardest to access and to the infrastructure that supports essential services. At the headquarters of the Governor's Office of Coclé, one of the sides of the building gave way completely, leaving the offices inside exposed. The part that remained standing showed cracks, according to reports released after the shaking. The damage to the Cathedral of San Juan Bautista in Penonomé added to the damage in hotels, businesses, and other buildings. Images circulating on social media showed facades with detachments and deteriorated structures in various parts of the country. In Panama City, the reaction was immediate: numerous residents abandoned buildings and skyscrapers due to the intensity of the movement. The height of these towers can intensify the perception of the shaking, and the evacuations spread through several streets of the capital. The Institute of Geosciences of Panama and civil protection agencies will continue monitoring seismic activity and the affected areas. In the coming hours, the authorities will have to establish the condition of the roads, water networks, and public buildings, while the aftershocks linked to the earthquake persist.