Figure 2. Vector diagram relating Caribbean plate (CA), Cocos plate (CO), Nazca plate (NZ), and Panama microplate (PM). Solid lines are relative plate motion vectors based on NNR-NUVEL-1B plate velocity model [DeMets, et al., 1990; Silver, et al., 1990; Shuanggen, et al., 2004]. PM velocity estimate from Bird, [2003]. Dashed black lines represent the orientations of the Panama Fracture Zone (PFZ) and Middle America Trench (MAT). Intersection is Panama triple junction (PTJ). PTJ migrates ~55 mm/yr southeast along MAT with respect to fixed PM. Dashed grey lines indicate PM-NZ and PM-CO convergence rates of ~20 mm/yr and ~80 mm/yr, respectively.