Geoscience Professor Jon Lewis and Walter Montero (retired, University of Costa
Rica) have been working to map active faults in Costa Rica for many years. In 2016 , they partnered with Cristina Araya, a recent seismology graduate from the University of Costa Rica, to document an active fault that traverses the tourist hotspot
near Arenal Volcano in western Costa Rica.
Their paper, titled
The Guanacaste Volcanic Arc Sliver of Northwestern Costa Rica," appeared May 11 in the open access journal Nature Scientific Reports.
Although it is well established that the Pacific coastal area of Costa Rica near the Nicoya Peninsula is moving northwestward as a tectonic sliver, the full extent of the sliver was not understood. Montero, Lewis, and Araya show that the likely boundary
for this sliver traverses the Guanacaste volcanoes of western Costa Rica nearly to the shores of Lake Nicaragua. This implies that Guanacaste volcanoes might be moving northwest relative to the rest of Costa Rica.
The findings have implications for understanding (1) the volcanic history of the region, (2) what drives the motion of the tectonic sliver, and (3) the geologic hazards posed to the population centers and the extensive energy infrastructure in the region.