Pakistan et la Zone de Subduction de Makran

Tectonic Setting: Two Subduction Systems

Pakistan's seismic hazard arises from two distinct tectonic settings that create very different earthquake types across its territory. In the north, the ongoing collision of the Indian Plate with the Eurasian Plate along the Himalayan and Hindu Kush ranges generates intense crustal seismicity and deep seismicity within the subducting Indian Plate slab — the same fundamental collision zone that threatens Nepal and northern India. In the south, the Makran Subduction Zone along Pakistan's Balochistan coast and continuing into Iran represents a Subduction ZoneA region where one tectonic plate dives beneath another into the mantle. Subduction zones produce the world's largest earthquakes (M8.5+) and are associated with deep ocean trenches and volcanic arcs. where the Arabian Sea oceanic crust descends northward beneath the Eurasian Plate — one of the world's slowest subduction zones but capable of generating megathrust earthquakes and devastating TsunamiA series of ocean waves generated by sudden displacement of the seafloor during an underwater earthquake. Tsunamis can travel across entire ocean basins at jet speed (700+ km/h).s.

The Makran Subduction Zone extends approximately 900 kilometers from the Strait of Hormuz eastward, with the Makran Accretionary Prism — the submarine wedge of sediment scraped off the descending plate — being one of the largest in the world. The very slow convergence rate of approximately 2 centimeters per year means that the Subduction ZoneA region where one tectonic plate dives beneath another into the mantle. Subduction zones produce the world's largest earthquakes (M8.5+) and are associated with deep ocean trenches and volcanic arcs. is relatively quiet most of the time, but this same slow movement implies that when the locked interface does rupture, it has accumulated significant strain over long periods. Paleoseismic evidence and historical records suggest the Makran produces major earthquakes roughly every several hundred years.

The 1945 Makran Earthquake and Tsunami

The most consequential historical event on the Makran Subduction Zone is the November 27, 1945 earthquake (magnitude 8.0–8.1), which generated a TsunamiA series of ocean waves generated by sudden displacement of the seafloor during an underwater earthquake. Tsunamis can travel across entire ocean basins at jet speed (700+ km/h). that killed approximately 4,000 people in Pakistan's Makran coast, Iran, Oman, and India. The TsunamiA series of ocean waves generated by sudden displacement of the seafloor during an underwater earthquake. Tsunamis can travel across entire ocean basins at jet speed (700+ km/h). arrived on the Makran coast within minutes of the earthquake, with wave heights of 12 to 15 meters reported at some locations, sweeping away coastal fishing villages with minimal warning. The 1945 event remains one of the few large tsunamigenic earthquakes ever recorded on the Makran, making estimation of the Earthquake Recurrence IntervalThe average time between major earthquakes on a particular fault. Estimated from paleoseismology and historical records. The Cascadia subduction zone has a recurrence interval of ~500 years. and future tsunami generation potential uncertain.

The Makran coast of Pakistan (Balochistan Province) is sparsely populated compared to the Indian Ocean coastal regions devastated in 2004, but the port city of Karachi — Pakistan's largest city and commercial capital, with a population of over 14 million — is located approximately 500 kilometers to the east of the main Makran seismic zone. A large Makran earthquake and tsunami would affect the Pakistani and Iranian coastlines and, depending on the rupture geometry and tsunami directivity, could reach Karachi with potentially dangerous wave heights. The cities of Mumbai in India and Muscat in Oman could also be affected by Makran tsunamis.

The Northern Seismic Threat: Kashmir and Beyond

Northern Pakistan's seismic hazard from the Himalayan collision zone is among the most severe in Asia. The October 8, 2005 Kashmir Earthquake (magnitude 7.6) struck in the disputed Azad Kashmir region of Pakistan, killing approximately 73,000 to 87,000 people — one of the deadliest earthquakes of the modern era. The death toll reflected the catastrophic collapse of Unreinforced Masonry (URM)Brick or block construction without steel reinforcement, which is extremely vulnerable to earthquake shaking. URM buildings account for the majority of earthquake fatalities worldwide. stone houses across hundreds of mountain villages, combined with the physical inaccessibility of many affected communities and the onset of winter that complicated rescue and relief operations.

The 2005 Kashmir earthquake and the subsequent response — coordinated by Pakistan's military and international relief organizations — highlighted both the extreme vulnerability of rural Himalayan construction and the logistical challenges of disaster response in mountainous terrain. Post-earthquake reconstruction programs introduced improved Building Code (Seismic)A set of legal requirements governing the design and construction of buildings to ensure minimum levels of earthquake safety. Updated after major earthquakes reveal new vulnerabilities. practices in some areas, but building back better in remote Himalayan villages requires sustained follow-through that is difficult to maintain over the years following a disaster.

Building Code Challenges in a Diverse Nation

Pakistan's Building Code (Seismic)A set of legal requirements governing the design and construction of buildings to ensure minimum levels of earthquake safety. Updated after major earthquakes reveal new vulnerabilities. situation reflects the country's economic and administrative diversity. Modern commercial construction in Karachi, Lahore, and Islamabad increasingly uses reinforced concrete and nominally follows current codes, though enforcement varies. Urban apartment and housing construction in secondary cities, and virtually all rural construction throughout Pakistan, uses load-bearing masonry — brick, stone, or adobe — with minimal or no seismic reinforcement. This Unreinforced Masonry (URM)Brick or block construction without steel reinforcement, which is extremely vulnerable to earthquake shaking. URM buildings account for the majority of earthquake fatalities worldwide. stock, spread across a vast territory with multiple high-hazard seismic zones, represents an enormous accumulated vulnerability.

The Makran TsunamiA series of ocean waves generated by sudden displacement of the seafloor during an underwater earthquake. Tsunamis can travel across entire ocean basins at jet speed (700+ km/h). threat to the Pakistani coast is particularly concerning from a preparedness perspective because no Indian Ocean TsunamiA series of ocean waves generated by sudden displacement of the seafloor during an underwater earthquake. Tsunamis can travel across entire ocean basins at jet speed (700+ km/h). has struck Pakistan's coast in living memory (the 2004 Indian Ocean tsunami was not generated by the Makran and caused minimal impact in Pakistan). This lack of recent experience makes public awareness of the TsunamiA series of ocean waves generated by sudden displacement of the seafloor during an underwater earthquake. Tsunamis can travel across entire ocean basins at jet speed (700+ km/h). hazard low, and Building Code (Seismic)A set of legal requirements governing the design and construction of buildings to ensure minimum levels of earthquake safety. Updated after major earthquakes reveal new vulnerabilities. provisions specifically addressing coastal tsunami risk are less developed than in countries with more recent TsunamiA series of ocean waves generated by sudden displacement of the seafloor during an underwater earthquake. Tsunamis can travel across entire ocean basins at jet speed (700+ km/h). exposure.

What Makes Pakistan Unique

Pakistan's seismic challenge is defined by the geographical extent of its high-hazard zones, spanning from the Himalayan collision in the north to the Makran subduction coast in the south, combined with widespread use of highly vulnerable construction types across a large, economically diverse population. The country's scientific institutions — including the Meteorological Department's Seismic Division and university research programs — have limited resources relative to the scale of the hazard. International partnerships and the engagement of the diaspora in risk communication have become important components of Pakistan's earthquake preparedness capacity.