ABSTRACT
The Sui Dome, which contains Pakistan’s major gas field, lies south of a mountain loop linking the Sulaiman range in the east with the Chaman fault and Kirthar range in the west. The structure includes beds of the Plio-Pleistocene Siwalik Group. Linear fissures recently exposed by excavation have been interpreted as seismic fractures but they are more probably joints which have been enlarged by subsurface erosion to produce pipes. True faults are few and small in throw. The field evidence accords with the seismic records. This suggests that the structure is now inactive, perhaps because strike-slip movement on the Chaman fault can cope with north-south shortening in this part of the axial belt.
