Azhar MahmoodRoll # 225

EVENING BBS APPLIED GEOLOGY

ACTIVE FAULTS OF PAKISTAN

PRESENTING TO: SIR MIRZA SHAHID BAIG

Active Fault• An active fault is a fault that is likely to become

the source of another earthquake sometime in the future. Geologists commonly consider faultsto be active if there has been movement observed or evidence of seismic activity during the last 10,000 years.

Fault is a weakness in the rock strata that can shift and create an earthquake.

4

Being located close to the collision boundary of the Indian and Eurasian plates, Pakistan lies in a seismically active zone. Owing to high population density near seismically active areas, it is imperative that buildings should withstand the seismic hazard to which these may be exposed during their life time.

OVERVIEW

Seismic Zoning map is prepared on a rigorous exercise based on compilation of geological, tectonic and seismicity data from Pakistan and its immediate surroundings. Only a brief account of salient seismotectonic features, seismicity and methodology adopted for seismic hazard zonation are mentioned here.

5

Pakistan is characterized by extensive zones of moderate to high seismicity, induced by the regional collisional tectonics associated with Indian and Eurasian plates and resulting in manifestation of great Himalayan and associated mountain ranges.

The geographic domain of Pakistan comprises a network of active seismotectonic defined five broad seismotectonic zones

1) Himalayan seismotectonic zone in the north,

2) Suleman-Kirthar thurst-fold belt,

3) Chaman-Ornach Nal Trasform Fault Zone,

4) Makran Subduction Zone in the west, and

5) Run of Kutch Seismotectonic Zone in the southeast.

The Pamir-Hinukush Seismic Zone straddles across Afghanistan and Tajikistan outside Pakistan but in close vicinity of the NW Pakistan comprising District Chitral.

Major Faults of Pakistan

6

1. Main Karakoram Thrust

2. Raikot Fault

3. Panjal-Khairabad Thrust

4. Riasi Thrust

5. Salt Range Thrust

6. Bannu Fault

7. Chaman Transform Fault

8. Quetta-Chiltan Fault

9. Pab Fault

10.Allah Bund Fault

11.Hoshab Fault

12.Makran Coastal Fault

Major Faults of Pakistan

Major active faults of Pakistan and surrounding areas that strongly influence the seismic hazard are listed below:

13.Main Mantle Thrust

14.Main Boundary Thrust

15.Himalayan Frontal Thrust

16.Jhelum Fault

17.Kalabagh Fault

18.Kurram Fault

19.Ornach-Nal Transform Fault

20.Kirthar Fault

21.Kutch Mainland Fault

22.Nagar Parkar Fault

23.Nai Rud Fault

Jhelum fault It is an important strike-slip fault trending north-south.Between Muzaffarabad and Kohala, this fault apparently dislocates the MBT and a left-lateral offset of about 30 km is indicted on the western limb of the syntaxis (see Figure 5-3). In this region of Murree, Abbottabad and Hazara the geological formations are extremely deformed as well as displaced several km south wards.It is the youngest and active major tectonic feature in the syntaxial zone. Based on the seismicity, the fault is quite an active one.

The Main Karakoram Thrust (MKT)

The Main Karakoram Thrust or the northern mega shear represents the collision zone ofthe southern margin of the Eurasian plate in Asia and extends into the Baltistan area. seismically active thrust with a large number of earthquakes of low tomedium intensity.

Punjal Thrust• Punjal thrust Fault is a significant active tectonic characteristic of some regional importance. It also comprised of several segments. This fault meets the Khairabad fault situated on Northern Attock Cherat range. Therefore, it is also known as Punjal- Khairabad thrust.

Kurram Fault•Kurram Thrust is a NNE-WSW trending north-ward dipping active tectonic feature separating the Kakar Khorsan Flysh basin in the north and the west from Bela Ophiolite thrust and fold belt in the east and south.

Chaman Transverse Fault

• Chaman fault is one of the major left-lateral transform faults of Pakistan. • Chaman fault is an active plate boundary which defines the western periphery of Indo-Pakistan plate. • It connects Makran convergence zone with Himalayan convergence zone (Indo-Pakistan plate is under-thrusting the Eurasian plate here).• Chaman fault is amongst the most significant and the active geodynamic features which has a wide fault zone.

Kirthar Fault• Kirthar fault along with the other N-S trending en-chelon faults of the Kirthar range front and foothills are considered seismically active.• A number of earthquake epicenters are located in this region, which have been associated with this fault.

Pab Fault• located along western boundary of Khude fold belt.• Pab thrust is considered seismically active, located in the north-west vicinity of Karachi.

Nai Rud Fault

• Nai rud fault is quite an active thrust fault. • Situated in the vicinity fold and thrust belt pertaining to the makran convergence zone and trending east-west.

Run of Kutch Fault

• Run of Kutch is an active fault of regional extent having an east-west orientation.• The extensions of this fault in the east as well as the west are, in fact, not so well-defined.• It is seismically active, which is evident byseveral major and minor earthquakes associated to this regional tectonic boundary.

13

SEMINAR ACI CODE

After NESPAK 2006

Tirich Mir-Misgar F.MKT

MMT

Panjal T.

MBT

Raisi T.Jhelum F.

Kalabagh F.

SRT

Indus-Kohistan F

Muzafarabad T.

Kurram T.

Waziristan T.

Sulaiman Frontal T.

Kirthar F.

Pab F.

OrnachNal F.MakranSubduction Zone

Chaman F.

Ghazaband T.

Hoshab F.

Hoshab F.

Rann of Kuchh F.

Fault Map of Pakistan

These zones of high seismic activity in Pakistan could very easily be recognized from this figure.