On 8 October 2005, at 08:50:39 PKT, a Mw 7.6 earthquake struck the Azad Kashmir region in northern Pakistan. Its epicenter was located in the tehsil of Patikka, near the city of Muzaffarabad. It caused catastrophic damage and tens of thousands of fatalities across Azad Kashmir and northwestern Jammu and Kashmir, India.
At least 87,350 people were killed and 200,000 were injured in Pakistan, with an additional 1,360 deaths and 7,082 injuries in India and 4 deaths in eastern Afghanistan. Among the fatalities were 26,000 killed by landslides, 19,000 students and teachers killed by collapsing schools, and 317 Pakistani and Indian military personnel. Muzaffarabad, Balakot, Bagh and Battagram were the worst-affected areas in Pakistan; all 4,000 inhabitants in the destroyed village of Jabri Kailash died. Severe damage also occurred in Kupwara and Baramulla districts in India, with the tehsil of Karnah almost completely destroyed. More than 856,400 buildings and houses were severely damaged or destroyed in Pakistan and India, with buildings collapsing as far away as Lahore. More than 3.5 million people were displaced, resulting in a severe humanitarian crisis for the region.
Kashmir lies at the southern margin of the broad zone of continental collision between the Eurasian and Indian plates. The rate of convergence between these plates near this location is 38 mm per year. The main structures involved in accommodating this convergence are large thrust faults, such as the Main Central Thrust and the Main Frontal Thrust. Within the frontal thrust zone, there are many individual thrust faults.
The region where the 2005 earthquake occurred crosses the political borders of Pakistan, India and neighboring countries. The earliest recorded quake occurred in 1255 in Kathmandu, Nepal. The Kashmir valley is completely surrounded by mountains, with the valley floor being 1,850 m (6,070 ft) above sea level, but the encircling mountains reach heights of 3,000–4,000 m (9,800–13,100 ft). Its unique geography makes it particularly prone to natural disasters, including floods, windstorms, avalanches, landslides, fires and droughts. It is, however, particularly prone to earthquakes as it lies on top of active geological faults where two tectonic plates, the large Eurasian and small Indian tectonic plates collide. This collision forces the Indian plate under the Eurasian plate, causing movement of the earth's crust.
The United States Geological Survey (USGS) and International Seismological Centre (ISC) both recorded a moment magnitude (Mw) of 7.6, and depths of 26 km (16 mi) and 15 km (9.3 mi), respectively. Its epicenter was located 10 km (6.2 mi) east-northeast of the town of Patikka in the Muzaffarabad District. The focal mechanism corresponded to reverse faulting on the Main Himalayan Thrust. A rupture area of 110 km (68 mi) x 40 km (25 mi) was estimated, with a maximum slip of 10.573 m (34.69 ft) north of Muzaffarabad. The observed source time function gives a 20 second duration for the earthquake, with the greatest phase of seismic moment release occurring about 10 seconds after initiation.
The earthquake resulted in a 75 km (47 mi) long surface rupture. It also triggered thousands of landslides, mainly rockfalls, debris falls and a debris avalanche. Landslides buried over 7,500 km2 (2,900 sq mi) of land, and caused nearly a third of the fatalities from the earthquake. There were two significant landslides, one in Chella Bandi, Muzaffarabad, and another in the Pir Panjal Range. The latter is considered the largest earthquake-triggered landslide and formed a new lake. The course of the Neelum River was altered by the landslides and the surface rupture. A waterfall also formed at the edge of the Kunhar River valley. It was observed that new co-seismic escarpments formed where sharp topographic changes existed. There are conflicting studies about the soil liquefaction aspects. This phenomenon and sand-blows were reported in the northwestern Kashmir Valley. However, one study did not observe any liquefaction.
The earthquake had a maximum Modified Mercalli intensity of XI (Extreme) evaluated in an area around the epicentre, between the towns of Muzaffarabad and Balakot. It was also assigned XI on the Environmental Seismic Intensity scale. Field surveys of heavy damage to buildings and other structures in Balakot determined that the Modified Mercalli intensity exceeded X (Extreme). At Muzaffarabad, the intensity peaked at IX–X (Violent–Extreme). Intensity VII–VIII (Very strong–Severe) was determined in the areas south of Muzaffarabad. A maximum peak ground acceleration (pga) of 0.231 g was recorded at Abbottabad.
The maximum intensity in India was MMI X in the towns of Uri and Karnah, and MMI IX in Kupwara and Handwara. Areas of eastern Afghanistan felt MMI IV–V (Light–Moderate). The earthquake was also felt throughout central Asia, and as far away as Dushanbe, Tajikistan and Almaty, Kazakhstan.
By the end of 2005, a total of 1,778 aftershocks were recorded. By the end of 2006, 357 aftershocks of Mw 4.0 or higher were recorded by the USGS; the largest aftershock measured Mw 6.4, striking at 15:46 PKT on 8 October with an epicenter northwest of the mainshock.
The Pakistani government's official death toll as of November 2005 stood at 87,350, although some initial estimates put the toll at over 100,000. Approximately 200,000 people were injured, and over 3.5 million were displaced. As of January 2010, thousands of people were still unaccounted for. The earthquake affected more than 500,000 families, and cold weather killed many who survived the earthquake.
By district, there were 33,724 deaths in Muzaffarabad, 24,511 in Mansehra, 8,157 in Bagh, 3,232 in Battagram, 1,025 in Poonch, 661 in Kohistan, 515 in Abbottabad, 447 in Neelum, 423 in Shangla, 6 in Mirpur and 4 in Sudhanoti. Additionally a school collapse in Rawalpindi killed one student and injured six. More than 780,000 buildings were severely damaged or destroyed in Pakistan, including 17,000 schools. About 80% of these were located in rural areas, including 50% of structures within the rupture zone. Overall economic losses from the earthquake amounted to US$6.68 billion.
Because the earthquake occurred during a school day in the region, most students were at school when the earthquake struck. In total, approximately 19,000 victims in Pakistan were students who died when their schools collapsed. Landslides were also responsible for 26,000 deaths, making it the fourth-deadliest landsliding event ever recorded, and the deadliest since the Vargas landslides in 1999. Many were also trapped in their homes, and because the earthquake occurred during Ramadan, most people were taking naps after their pre-dawn meal and had little time to escape. Women made up a larger portion of casualties as many were inside cleaning after the morning meal. At least 215 Pakistani soldiers also died.
In Balakot, about 90% of the buildings were reduced to rubble, and 30,000 people were feared dead, while in the city of Muzaffarabad, 23,000 people were killed and almost every building was either destroyed or damaged. The village of Jabri Kailash, near the epicenter, was completely destroyed, with its entire population of 4,000 believed to have been wiped out. In Garhi Habibullah, 2,000 people were killed, including 403 students after a school collapsed. Up to 1,000 people were killed after a landslide struck the town of Hattian Bala.
Around 574 health facilities were reported to have been partially damaged or destroyed. In Pakistan, around 320 health institutions were destroyed and 44 were partially damaged. The resulting landslides from the earthquake affected transport, with closure of essential roads and highways. Sections of a road and pavement in a major route in Muzaffarabad collapsed. Many bridges were damaged, with the largest damaged bridge in Balakot. Several other bridges in the Jhelum Valley (Kashmir) were also damaged. The bridges in Muzaffarabad were not damaged except for a pedestrian suspension bridge north of the city which collapsed. 3,994 water supply systems were destroyed. In Muzaffarabad and Balakot, the electricity network was destroyed. In Balakot, some pylons were tilted. The GSM network withstood the impact of the earthquake better. In both towns, the Mobilink operator was functional, but was saturated and experienced intermittent signal, and was therefore unreliable. In contrast, landline telephone infrastructure was completely destroyed. It was estimated that about 40% of telecommunication exchanges, and 15% of telephone lines in Azad Jammu and Kashmir were disrupted. In the North-West Frontier Province, it was estimated that 30% of exchanges and 8% of lines were disrupted.