Damage

The earthquake killed at least 825 people and injured hundreds of others.^[3] The earthquake struck a sparsely populated region of Pakistan. Most homes and buildings in the region are constructed of mud bricks and collapsed during the earthquake and aftershocks. An official in the Balochistan province claimed that 80 percent of the homes in the Awaran District had collapsed or were damaged.^[11] In the regional capital Quetta, some areas appeared to be badly damaged.^[12][13] Officials from the Balochistan government estimated that at least 21,000 houses had been completely destroyed by the tremor, while some areas remained beyond the reach of rescue services 48 hours after the initial quake.^[4]

PAGER impact estimates from the United States Geological Survey included a red alert level for initial shaking-related fatalities (35% chance of 1,000–10,000 fatalities, 27% chance of 10,000–100,000 fatalities) and an orange alert level for economic impact (35% chance of US$100 million–$1 billion, 26% chance of US$1–10 billion).^[14]

The earthquake was felt in major cities across Pakistan, including Karachi, Hyderabad, Rawalpindi/Islamabad, Larkana, and Lahore.^[10] The quake was also felt in Delhi, India, where some buildings shook,^[15] and Muscat, Oman—800 kilometres (500 mi) from the epicenter—where mild tremors shook tables and cabinets.^[16] The earthquake shook in the parts of UAE, Iraq, Afghanistan, Iran and Qatar.^[17] The earthquake also shook Saravan, Iran without causing any damage or casualties.^[18] There were also minor tremors and aftershocks in the United Arab Emirates.^[19]

Ground effects

Satellite images of Zalzala Jazeera off the coast of Gwadar

The earthquake was apparently powerful enough to raise a small island, later dubbed Zalzala Jazeera, meaning "quake island", in the Arabian Sea, variously reported as being 350 metres (1,150 ft) to 1 kilometre (0.62 mi) off the shore of Gwadar.^[13][20][21] The island is partially composed of rock, but mostly consists of mud and sand. The oval-shaped island was 60–70 feet (18–21 m) high and about 200–300 feet (61–91 m) long according to local people that visited the island the day after it appeared. They noticed a smell of gas and managed to ignite it, later extinguishing it with difficulty.^[20]

The island is believed to be the result of a mud volcano.^[22] In the region, deposits of frozen gas hydrates—which have a large methane content—exist beneath 300 to 800 metres (980–2,620 ft) of compressed sediment.^[20] After such a large earthquake, the gas hydrates converted from frozen to gaseous form through the heat of friction and either raised the overlaying sediment enough to create fissures through which it escaped or rose through fissures resulting from the earthquake itself. Another possible contributing factor in the island's creation was the liquefaction of the seabed, which allowed finer, loosely packed sediments to become liquid-like and squeeze up through fissures in overlying compressed sediment. Locals who ventured to the island shortly after it formed heard a hissing noise at one end and started a fire which was difficult to extinguish. There are several mud volcanoes inland near Zalzala Jazeera and they are common in the vicinity of subducting plate boundaries; in fact, similar islands have appeared in the same region following earthquakes in 1945, 1999, 2001, and 2010. Because of its composition of softer sediments, the sea was predicted to erode the island completely within a few months.^[20] By the end of 2016, the island had completely disappeared.^[23]

Tsunami

Despite its inland epicentre, the earthquake generated a tsunami with a maximum height of 0.57 m (1.9 ft) in eastern Oman.^[24]

Aftershocks

• mb 5.8 earthquake at 27°12′32″N 65°34′01″E / 27.209°N 65.567°E / 27.209; 65.567 (Aftershock 1 M5.8 USGS) occurred at 11:36:27 UTC (16:36:27 PKT) on 24 September at a depth of 10.0 km (6.2 mi).^[25]
• mb  5.6 earthquake at 27°18′47″N 65°37′12″E / 27.313°N 65.620°E / 27.313; 65.620 (Aftershock 4 M5.6 USGS) occurred at 13:01:39 UTC (18:01:39 PKT) on 24 September at a depth of 14.5 km (9.0 mi).^[26]
• mb  5.5 earthquake at 27°07′52″N 65°28′16″E / 27.131°N 65.471°E / 27.131; 65.471 (Aftershock 7 M5.5 USGS) occurred at 17:20:13 UTC (22:20:13 PKT) on 24 September at a depth of 10.5 km (6.5 mi).^[27]
• M_ww  6.8 earthquake at 27°10′59″N 65°30′18″E / 27.183°N 65.505°E / 27.183; 65.505 (Aftershock 11 M6.8 USGS) occurred at 07:34:06 UTC (12:34:06 PKT) on 28 September at a depth of 12.0 km (7.5 mi).^[28]