Deformation and Earthquake Potential on the North America–Caribbean–Cocos Plate Boundary System in Guatemala

Abstract In Guatemala, the Cocos, North American, and Caribbean plates interact to create a region of high seismic risk. Previous analyses of crustal faults in the country have been overly simplified, creating discrepancies between geologic and geodetic slip rate models. This study uses geodetic, seismic, and geologic data to develop new strain rate maps and faulting models. The spatial distribution of locking on crustal faults matches historic large earthquakes, and multiple minor faults accommodate strain between the North America and Caribbean plates. Moment deficit rates from Kostrov‐type and elastic fault models give 0.66–1.3 × 10 19 N m/yr and 0.73–0.89 × 10 19 N m/yr, respectively, excluding the subduction zone. Historic earthquake moments total 0.21–0.37 × 10 19 N m/yr, suggesting fault creep and bulk inelastic strain balance the moment budget. Finite element modeling of the fault system shows that long‐term slip rates agree better with geologic slip rate estimates when including minor faults and inelastic bulk crustal strain. Consistent with previous studies, the forearc sliver between the subduction zone and volcanic arc is sutured to the North American Plate, and the Caribbean Plate escapes eastward, causing extension in western Guatemala.