Date of Award


Degree Type


Degree Name

Master of Science (MS)



First Advisor

Dr. Paulo Hidalgo-Odio


The chronostratigraphy from >50,000 BP to the present was determined for the overlapping tephra deposits from Barva and Poas volcanoes, located 20 km north of San Jose, Costa Rica, using stratigraphic correlations supported by fourteen C14 ages. The 16 km proximity of the cones, the abundance of vegetation that overlays the tephra facies, high rates of weathering and erosion, and presence of cinder cones make unraveling the eruptive history of the two volcanoes problematic. Previous attempts have been made to develop an eruptive history of the tephra deposits between the Barva and Poás volcanoes, but relied on stratigraphic correlations based only on physical characteristics of tephras. Developing an accurate eruptive history is crucial for the assessment of volcanic risk, which could prove imperative to surrounding communities that could be significantly affected by caving roofs, disrupted agriculture and water supply, and respiratory ailments.