1. A Secure User Plane Location (SUPL) enabled terminal (SET) comprising: at least one processor configured to: receive a first message from a Home SUPL Location Platform (H-SLP) to initiate a triggered location session, the first message including a trigger type, wherein the trigger type is an area event; transmit a second message to the H-SLP to start the triggered location session in response to the first message; receive a third message in response to the second message, the third message including a definition of the area event; determine at least one position estimate for the SET in response to the definition of the area event; report the at least one position estimate for the SET to the H-SLP.