Active Fault Map of N. Pakistan

Principal Investigator: M. Asif Khan
Project Participants: M. Waqas Javed, Muhammad Sayab
Sponsors: Earthquake Model Middle East (EMME), a component of GEM (Global Earthquake Model)

Faults, together with seismicity record (geological, historical and instrumental) form basis of seismic hazard analyses. The existing fault data from Pakistan however, lack several parameters crucial for seismic hazard analyses. Poor seismicity records together with poor data on fault parameters renders exiting seismic hazard analyses unreliable.

In order to overcome part of the problem, a new fault map of northern Pakistan is compiled, together with a database of parameters such as segmentation, sense and direction of movement, dip, rake, slip rate, activity status (active/dormant/potentially active), and seismogenic upper and lower depths. This information is crucial for using faults as potential seismic sources in seismic hazard analysis, and will fulfil a longstanding requirement, hitherto lacking in Pakistan.

The faults included in this map and database are based on our past field observations, deduced from image analysis of aerial photographs and satellite images, and compiled from published literature. The same datasets are used for deduction of fault parameters. The faults which we list as active include evidence of their offset of Quaternary and younger sediments. Seismicity with clusters of seismic events associated with a particular fault is also taken as an evidence of active nature of the fault. Rest of the faults, which lack clear evidence of Quaternary or younger activity, are classified as potentially active faults.

We have used ArcGIS 9.3 for preparation of the map and attribute tables for database. A 70m resolution SRTM digital elevation model is used as the base map for displaying the faults. The GIS application enables continuous updating of the active fault map and the associated database in future.