Resumo

ARAYA, María C.; LINKIMER, Lepolt; MONTERO, Walter  e  ROJAS, Wilfredo. The Tobosi fault: source of the 2011-2012 Tobosi earthquake swarm in central Costa Rica. Rev. Geol. Amér. Central [online]. 2015, n.53, pp.89-102. ISSN 0256-7024.  http://dx.doi.org/10.15517/rgac.v53i0.21145.

The Central Costa Rica Deformed Belt (CCRDB) is an ~100-km broad zone of deformation that marks the boundary between the Caribbean Plate and the Panama Microplate. From December 2011 to February 2012, an earthquake swarm took place in a portion of the CCRDB, near the town of Tobosi, 7 km southwest of the city of Car-tago. In this study, data recorded by the National Seismological Network of Costa Rica (RSN: UCR-ICE) is used to relocate the earthquakes and calculate their focal mechanisms. Additionally, the tectonic geomorphology of the region is analyzed. The results show a transtension structure near the town of Tobosi, which comprises at least three faults, named: the Tobosi, Tablon, and Alumbre faults. It was found that the Tobosi fault is an active left-lateral strike-slip fault with a normal component and was the source of the Tobosi earthquake swarm.

Palavras-chave : Active fault; earthquake swarm; seismic hazard; Tobosi; Costa Rica; focal mechanisms.

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