The Huanghua Depression is a pull apart basin located at the center of the Bohai Bay  Basin. The Huanghua Depression has four major faults including NNE-trending strike-slipping boundary faults, NEE-trending regional extensional faults, E-W trending secondary extensional faults and N-S trending transfer zones such as the coastal transfer zone and the Kongdian heave. The basin underwent four stages of evolutions including Eocene propagating rifting called Kongdian event, Early Oligocene pull-apart graben called Jiyang event, Late Oligocene half-graben called Dongying event and Miocence-Pleistocene thermal depression under dish-like bukling.