Plates in the study area. (a) Example of small plates. The letters indicate a set of plates whose relative displacement is reconstructed in panel (b) from initial (left) to current configuration (right). Pressure ridges have been created at some of the contacts between the plates. (c) Image positions. (d) Example of a field with larger plates. (e) Lava fields of the Laki volcano in Iceland (reference map below). The arrows indicate some of the grooves produced by the lava flow against protruding obstacles and are oriented along the direction of motion.