This paper mainly analyses the tectonics, island chains and fractures as reflected from 180-order satellite gravity anomaly calculated based on GEM (sub 10) C model. The Marshall and Line Island chains are uniformly dislocated during the late stage of their formation, which is the western extension of the Clarion fracture zone and parallel to the western extension of the Mendocino fracture zone. The latter zone once caused offset of magnetic anomaly belt in the west of Hawaii. Typical of hot spot genesis, the Hawaiian Islands chain displays a unique gravity anomaly which was believed to share the same forming mechanism with Marshall and Line Islands chains. However, in respect of great difference in their anomaly pattern, hot spot energy is believed to be weaker for the latter two islands. Age relationship of several groups of fractures is also elaborated based on anomaly pattern. It is assumed that the Cretaceous magnetic quiet zone of the subsided Darwin Rise might be related to thermal demagnetization in the area, when it rose.