High-resolution seismicity data from Costa Rica and southern Nicaragua have been used to image the geometry of the Wadati-Benioff zone under southern Central America. The data include 9,514 events with computed horizontal and vertical errors smaller than 4 and 5 km respectively.

We found that under the Nicaragua-Costa Rica border the Wadati-Benioff zone contorts (from steep to shallow dip angles, northwest to southeast) but does not show evidence of a brittle tear, as postulated by others. Further to the southeast—northeast from Puerto Caldera—the Wadati-Benioff zone does, however, show a tear (the Quesada Sharp Contortion) at intermediate depths (h > 70...