Costa Rica is part of the Central America volcanic front. Formed by the subduction of the oceanic Cocos plate underneath the continental Caribbean plate and the Panama block, a process that initiated ~ 5 Ma. Subduction rates varies from 85 to 90 mm/yr along the Middle America Trench which in Costa Rica, extents from the Northern part of the Nicoya Peninsula until the Southern most part of the country, in the Osa peninsula. Besides abundant microseismicity (~15000+ earthquakes per year) and related earthquake-type processes, megathrust earthquakes (M7-M7.6) occur every 40 to 50 years. In conjunction with a very active volcanism, they are the main mechanisms shaping the morphology, geology and biota distribution in the country.
In this field trip we intend to show and explain the origins of the Nicoya Peninsula. We are going to identify different rock formations and their compositions. We are going to visit and explore the geology around Nosara, Ostional, San Juanillo and Playa Negra to finally visit one of the 80 state-of-the-art seismic and GPS stations from OVSICORI that continuously monitor the megathrust activity right underneath the Nicoya Peninsula.