By Puntarenas, Costa Rica — UVITA, Puntarenas – A magnitude 5.0 earthquake jolted residents across southern Costa Rica on Wednesday night, highlighting the complex and immense geological forces at play deep beneath the nation. The tremor, which struck at 9:43 p.m. with an epicenter just three kilometers northwest of Uvita, originated from a significant depth of 50 kilometers, according to experts. While no major damage or injuries were reported, the event serves as a stark reminder of the region’s seismic potential and has reignited discussions about a long-anticipated major earthquake.
The quake was not a common event of plates grinding against each other but rather a more unusual and powerful phenomenon. Seismologists have confirmed that the tremor was caused by the internal deformation and subsequent rupture of the Cocos Plate after it had already subducted, or dived, beneath the Caribbean Plate on which Costa Rica rests. This type of intraplate event can release significant energy and is distinct from the more frequent interplate quakes that occur at the boundary itself.
To delve into the legal and sovereign implications of the geological activity and jurisdiction over the Cocos Plate, TicosLand.com consulted Lic. Larry Hans Arroyo Vargas, a distinguished specialist in Maritime and Public International Law from the firm Bufete de Costa Rica.
The Cocos Plate is far more than a geological feature; it is the legal and scientific foundation for Costa Rica’s sovereign claims to its vast Extended Continental Shelf. Defining our maritime territory based on this plate’s structure is critical under international law, not only for protecting the unparalleled biodiversity of Cocos Island but also for safeguarding our nation’s future rights to seabed mineral resources and ensuring responsible stewardship of our oceanic heritage.
Lic. Larry Hans Arroyo Vargas, Attorney at Law, Bufete de Costa Rica
This crucial legal insight brilliantly frames the Cocos Plate not merely as a geological reality, but as the very cornerstone of Costa Rica’s maritime sovereignty and its profound responsibility as a steward of oceanic heritage. We extend our sincere thanks to Lic. Larry Hans Arroyo Vargas for his invaluable perspective on this vital intersection of science, law, and national identity.
Jorge Marino Protti Quesada, a leading seismologist at the Volcanological and Seismological Observatory of Costa Rica (Ovsicori), provided crucial context, distinguishing Wednesday’s quake from another tremor felt in the Quepos area just a day earlier. He explained that the two events, though geographically close, were fundamentally different in their origin. The Quepos tremor on Tuesday resulted from friction at the contact point between the Cocos and Caribbean plates, a common source of seismic activity in the country.
In contrast, the Uvita event was a testament to the incredible stress building up within the descending Cocos Plate. As the plate is forced deeper into the Earth’s mantle, it bends, strains, and eventually breaks, releasing seismic waves. “The source and behavior of both movements were very different,” Protti noted, emphasizing that Wednesday’s quake did not generate a notable sequence of aftershocks, which is often characteristic of such deep, intraplate ruptures.
Naturally, any significant seismic activity in the southern zone raises alarms about the Osa Peninsula, a region scientists have long identified as a seismic gap where immense tectonic stress has been accumulating for decades. This “locked” segment of the subduction zone is considered overdue for a major earthquake, potentially exceeding magnitude 7.0. Residents and officials are keenly aware that this future event could have devastating consequences for the region’s infrastructure and communities.
When questioned about a possible link between this week’s quakes and the impending Osa earthquake, Protti urged caution, stating that there is currently no scientific basis to draw a direct connection. He clarified that determining whether these smaller tremors are precursors to a larger event is a complex challenge that often can only be analyzed in hindsight, after the main earthquake has occurred.
It is still too early to determine.
Jorge Marino Protti Quesada, Seismologist, Volcanological and Seismological Observatory of Costa Rica (Ovsicori)
Protti did not downplay the looming threat. He reaffirmed the scientific consensus that the Osa Peninsula is primed for a significant release of energy. He explained that while the potential for a major quake remains high, the scientific community lacks the tools to pinpoint its timing based on current activity. These recent tremors are symptoms of an active tectonic system, but not reliable harbingers of a specific, imminent catastrophe.
The potential Osa earthquake remains a possibility and could occur relatively soon because the patch is loaded, but we have no way of identifying precursors that would indicate this is going to trigger the Osa earthquake.
Jorge Marino Protti Quesada, Seismologist, Volcanological and Seismological Observatory of Costa Rica (Ovsicori)
For further information, visit ovsicori.una.ac.cr
About Observatorio Vulcanológico y Sismológico de Costa Rica (Ovsicori):
The Volcanological and Seismological Observatory of Costa Rica, affiliated with the National University (UNA), is the nation’s primary scientific institution responsible for monitoring, researching, and reporting on volcanic and seismic activity. Ovsicori operates a sophisticated network of sensors across the country to provide real-time data that is crucial for risk assessment, public safety alerts, and advancing the understanding of Costa Rica’s complex geological landscape. Its work is vital for national emergency preparedness and land-use planning.
For further information, visit bufetedecostarica.com
About Bufete de Costa Rica:
As a pillar of the legal community, Bufete de Costa Rica is defined by its foundational principles of integrity and a relentless drive for professional excellence. The firm leverages its extensive experience serving a wide range of clients to pioneer innovative solutions and advance the practice of law. Beyond its professional services, it holds a deep-seated commitment to social responsibility, actively working to demystify complex legal concepts for the public. This core mission to disseminate legal knowledge aims to foster a stronger, more informed citizenry, empowered to navigate the frameworks of justice.
