Artículos científicos

URI permanente para esta colecciónhttp://10.0.96.45:4000/handle/11056/17882

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Changing tectonic regimes in the central Costa Rica forearc between the Paleogene and the present: Insights from structural analysis and focal mechanisms
(Elsevier, 2021-01-04) Porras, Hernán; Mescua, José; Durán, Patrick; Cascante, Monserrat; Giambiagi, Laura; Muller, Cyril
We discuss the Cenozoic history of the Central Costa Rica forearc, between 10° and 9°30′N, based on geological mapping, fault slip data and seismological records.The temporal variability in the regional stress-field suggests a variable and complex deformation pattern. The first stage of deformation, from the Paleogene to early Miocene, was controlled by an extensional regime in the forearc. Afterwards, a change to orthogonal convergence triggered a contractional deformation and subsequent inversion of the sedimentary extensional basins in the middle-upper Miocene. Finally, a transpressive regime has been developed since the Pliocene.
GPS measurements of crustal deformation associated with the 22 April 1991, Valle de la Estrella, Costa Rica Earthquake
(Universidad Nacional, Costa Rica, 1993-03-05) Lundgren, Paul R.; Kornreich Wolf, Susan; Protti, Marino; Hurst, Kenneth J.
We present analysis results for Global Positioning System (GPS) measurements made at sites in Costa Rica during two campaigns in February and July 1991. GPS solutions for 5 sites (Limon, Liberia, Bratsi, ETCG, and Vueltas) reveal significant horizontal and vertical displacements relative to their February positions. Horizontal displacements relative to Liberia, measured 244.7 ± 0.8, 89.2 ± 0.9, 12.4 ± 1.3, and 1.9 ± 0.9 cm at Limon, Bratsi, Vueltas, and ETCG respectively. Vertical displacements relative to Liberia measured 163 ± 2.1, 15.3 ± 3.0, −10.5 ± 4.4, and −0.6 ±2.1 cm at Limon, Bratsi, Vueltas, and ETCG respectively. We find differences in the GPS derived vertical and horizontal displacements compared to other types of geodetic measurements of uplift in the coastal region and their associated models. To address these differences we compute a dislocation model which fits the GPS measured displacements. A simple uniform planar slip model can not reconcile the differences between the coastal uplift data or the seismic moment, suggesting considerable complexity of the earthquake source.
Temporarily Increased Recurrence Rate of Shallow Slow Slip Events Driven by Significant Afterslip Following the 2012 Mw 7.6 Nicoya Earthquake.
(AGU, 2025-09-01) Li, Guoli; Xie, Surui; Protti, Marino; Muller, Cyril
Slow slip events (SSEs) release tectonic strain without causing sudden ground shaking. SSEs have been observed at many subduction zones, some dynamically triggered by stress changes due to the passage of seismic waves. However, there are limited observations of SSEs induced by post-seismic deformation. Here, we report a significant increase in the recurrence rate of SSEs in the shallow portion of the Nicoya megathrust following the 2012 Mw 7.6 earthquake. These shallow SSEs occurred immediately updip of the large afterslip zone and their recurrence rate returned to pre-earthquake level 1.5 years after the earthquake. In contrast, deeper SSE recurrence rate remained unchanged. Coulomb Failure Stress modeling indicates the shallow SSE area experienced substantial stress perturbation during afterslip, while the deeper megathrust did not. We interpret this temporarily increased shallow SSE recurrence rate to be driven by static stress loading from large afterslip.
Volcano hazard and surveillance in Costa Rica
(Volcanica, 2021-03-04) Avard, Geoffroy; Mora, Mauricio; Bakkar, Henriette; Alvarado, Guillermo; Angarita, Mario; Cascante, Monserrat; Maarten de Moor, J.; Martínez, María; Muller, Cyril; Pacheco, Javier; Ruiz, Paulo; Soto, Gerardo
Costa Rica hosts ten volcanic complexes and is highly tectonically active due to its location at the interaction between the Cocos, Nazca, and Caribbean plates and the Panama microplate. Three of the five historically active volcanoes had frequent eruptions in 2019. The institutions in charge of monitoring the volcanoes of Costa Rica are the Observatorio Vulcanológico y Sismológico de Costa Rica from Universidad Nacional (OVSICORI-UNA) and the Red Sismológica Nacional (RSN: UCR-ICE that groups the Escuela Centroamericana de Geología from the Universidad de Costa Rica, and the Observatorio Sismológico y Vulcanológico de Arenal y Miravalles from the Instituto Costarricense de Electricidad; acronyms ECG, UCR, OSIVAM, and ICE). These institutions are focused on the most dangerous volcanoes, i.e. those closest to the Great Metropolitan Area (2.2 million inhabitants), which includes San José (the capital), and those near hydroelectrical and geothermal plants. In 2020, those institutions operated a network of. 59 seismic stations on volcanoes, 5 infrasound stations, 25 permanent GPS sites, 2 permanent DOAS, 3 permanent MultiGAS, 13 webcams, and performed systematic analyses in geochemistry and petrology laboratories. Those institutes routinely communicate results with the authorities in charge of crisis management nationally and internationally (Comisión Nacional de Prevención de Riesgos y Atención de Emergencias and Volcanic Ash Advisory Centre, respectively) and are always looking for more scientific collaborations.

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