wedge. This is where piggyback basins form. The foredeep is the thickest sedimentary zone and thickens toward the orogen. Sediments are deposited via distal fluvial, lacustrine, deltaic, and marine depositional systems. The forebulge and backbulge are the thinnest and most distal zones and are not always present. When present, they are defined by regional unconformities as well as aeolian and shallow-marine deposits. Sedimentation is most rapid near the moving thrust sheet. Sediment transport within the foredeep is generally parallel to the strike of the thrust fault and basin axis. Plate motion and seismicity The motion of the adjacent plates of the foreland basin can be determined by studying the active deformation zone with which it is connected. Today GPS measurements provide the rate at which one plate is moving relative to another. It is also important to consider that present day kinematics are unlikely to be the same as when deformation began. Thus, it is crucial to consider non-GPS models to determine the long-term evolution of continental collisions and in how it helped develop the adjacent foreland basins. Comparing both modern GPS (Sella et al. 2002) and non-GPS models allows deformation rates to be calculated. Comparing these numbers to the geologic regime helps constrain the number of probable models as well as which model is more geologically accurate within a specific region. Seismicity determines where active zones of seismic activity occur as well as measure the total fault displacements and the timing of the onset of deformation. Formation of basins Foreland basins form because as the mountain belt grows, it exerts a significant mass on the Earth's crust, which causes it to bend, or flex, downwards. This occurs so that the weight of the mountain belt can be compensated by isostasy at the upflex of the forebulge. The plate tectonic evolution of a peripheral foreland basin involves three general stages. First, the passive margin stage with orogenic loading of previously stretched continental margin during the early stages of convergence. Second, the "early convergence stage defined by deep water conditions", and lastly a "later convergent stage during which a subaerial wedge is flanked with terrestrial or shallow marine foreland basins". The temperature underneath the orogen is much higher and weakens the lithosphere. Thus, the thrust belt is mobile and the foreland basin system becomes deformed over time. Syntectonic unconformities demonstrate simultaneous subsidence and tectonic activity. Foreland basins are filled with sediments