Abstract: In some embodiments, a method of determining the location of fracturing fluid in a subterranean formation includes providing purpose-designed additives (PDA) in the fracturing fluid. As the fracturing fluid moves through a fracture in the formation, the PDA solidifies and forms a barrier in the path of the fracturing fluid. In response to a pressure increase in the well contacting the barrier, at least one signal is generated and detected to provide information about the fracturing fluid and/or fracture.