DAWN - Features; October 25, 2005

Published Oct 25, 2005 12:00am

LAHORI’S NOTEBOOK: The great Quetta tragedy

LAST week, I gave you an account of the great Kangra earthquake of 1905 in which around 20,000 people lost their lives. Thirty years later, Quetta was devastated by another great earthquake in 1935 in which the casualties were far higher than in Kangra and adjoining areas. I have taken the following account of the Quetta tragedy from the Amateur Seismic Centre:

QUETTA

Date               : May 30, 1935
Location         : 4.0 kilometres SW of Ali Jaan (Balochistan), Pakistan
Latitude          : 28.870o N
Longitude       : 66.400o E
Origin Time     : 21:33 UTC
Magnitude       : Mw 7.7, Mw 7.8, Mw 8.1, Ms 7.7
Moment          : 0.35*10*21 Nm, 0.63*10*21 Nm, 1.75*10*21 Nm

A powerful earthquake devastated the town of Quetta and the adjoining areas on the morning of May 31, 1935. Nearly 35,000 people are believed to have been killed, most of those fatalities in Quetta alone. This the deadliest known earthquake in the Indian sub-continent. Tremors were felt over much of Pakistan and as far as Agra in India.

The quake was centred 4.0 kilometres SW of Ali Jaan (Balochistan), Pakistan,

Or 9.7 kilometres E of Badduzai (Balochistan),
Or 22.3 kilometres SW of Kalat (Balochistan),
Or 75.8 kilometres ESE of Chagai (Balochistan),
Or 108 kilometres SSW of Mastung (Balochistan),
Or 153 kilometres SSW of Quetta (Balochistan),
Or 231 kilometres NW of Larkana (Sindh),
Or 440 kilometres NNW of Karachi (Sindh).

The earthquake occurred at 02:33am local time (PST) on May 31, 1935. The moment magnitude (Mw = M) of this earthquake has been estimated at M7.7 based on geometric seismic moment. A previous estimate of M8.1 is believed to have been an overestimate (Bilham, personal communication). No uplift was found in thrust faults to the southwest of Quetta by surveys carried out after the earthquake. However, 20 centimetres of uplift was recorded to the west of the town. Ground deformation extended for 105 kilometres from the south side of the Chiltan range to Kalat, which was mostly in the form of 2-20 centimetre cracks in alluvium. The ground on the western side of the cracks near Mastung was found to have risen on average up to 80 centimetres while in some places the earth was heaved up several metres. Near Mastung Road railway station, the cracks ran across the Quetta-Nushki railway and deforming and offsetting the tracks vertically. These cracks indicate that the quake was associated with a zone of faults that run along the eastern edge of the Chiltan range extending southwards toward Mastung and Kalat. This leads to the understanding that the earthquake occurred on a strike-slip fault within the Ghazaband Fault Zone. The 1931 Sharigh and Mach earthquakes which occurred nearby are believed to have increased stresses on a fault in this zone which failed in 1935. An updated epicentral location for this earthquake was derived from P-wave data from 231 stations, using present ISC procedures and is in the vicinity of earlier epicentral locations.

The town of Quetta saw most of the fatalities, and this earthquake has since been known as the Quetta Earthquake. The civil lines was completely destroyed and up to 15,000 people are thought to have perished here alone. The police lines, the darbar hall, the civil and mission hospitals and the club were ruined. A few reinforced concrete structures and the new railway quarters escaped with minor damage. The cantonment suffered much less damage, but a few buildings did collapse. That too was confined to a kilometre wide stretch that lay along the civil lines and the Durani Nullah, one of two watercourses that ran through the town. The fort was also damaged and many buildings collapsed. In the Royal Airforce lines, the hangers at the airfield were all that were left standing though they were badly damaged. Every aircraft was rendered unsafe to fly. Piped water was not disrupted in Quetta and power supply carried on with a restricted load. Up to 26,000 people are believed to have been killed in Quetta alone and a few thousand bodies were left buried in the ruins. Most of the administration in Quetta was killed, but troops from the military base organized rescue quickly. They evacuated survivors and cordoned off the town to prevent looting and the outbreak of epidemic as well as provided protection and salvaging property from destroyed structures. They also carried out mass burials or cremations of the dead. Letters written during that period by survivors contain vivid descriptions of the earthquake and its aftermath.

Outside of Quetta to the south, Mastung was flattened along with the Khan’s palace and 1,736 people were killed. The village of Sariab was razed to the ground and 1,206 people were killed. 1,010 lives were lost at Kansi which was also destroyed. 710 people were killed at Tiri and 369 at Pringabad. 120 died at Kalat and much of town was laid to waste. All villages between Quetta and Kalat were destroyed with about 70 per cent of the population dead or injured. In the state of Kalat, 2,900 were killed and 5,000 injured. Nearly 100 villages in this region were devastated. In the Kalat tribal area, 8,410 deaths were recorded. Though the total number of fatalities from this quake are a mere estimate, it is believed nearly 35,000 people might have perished, making this earthquake the deadliest in the entire sub-continent in recent history.

Communication was disrupted owing to telegraph lines from Kalat and Quetta to Chaman and Jacobabad being broken. A radio link was established, however, with Shimla. Transportation routes were not badly damaged though five segments of the Quetta-Nushki railway track had to be replaced as they ran within a zone of fissures. Widespread liquefaction was observed in the valley to the northwest of Quetta. Mud volcanoes were reported from this location as well also from near the village of Thok, near Surab. The eruption of the mud volcano at the latter lasted nine hours.

Away from the meizoseismal region, damage to dilapidated buildings was noted at many places in the Indus Valley and at Kandahar and Spin Boldak in south-eastern Afghanistan. The earthquake was felt throughout present-day Pakistan, from Jatti in the south near Karachi, Dera Ismail Khan in the north and Chagai in the east. It was also felt at Amritsar and Shimla and as far as Sultanpur and Agra. The extent to which the shock was felt in Afghanistan is unknown. It was previously believed that the quake was not felt very widely.

Nor foreshocks were felt before the earthquake. However, earthquake lights were seen before the mainshock. A bright light was observed in the west from Quetta and near Kalat flashes of light were reported along the flanks of the mountains. Many aftershocks were felt in the region though most of them were small in magnitude and were felt up to October of the same year. The largest aftershock occurred on June 2, 1935, and had a magnitude of Mw 5.8. It caused additional damage to Mastung, Maguchar and Kalat, but none at Quetta. Landslides occurred in the Shirinabad valley and rockfalls in the Chiltan range. Dust clouds from these landslides and rockfalls were seen rising 500 metres above the mountains. Nushki might also have suffered some damage in this aftershock.

* * * * *

ANOTHER earthquake hit the northern Pakistan claimed thousands of lives. Here is a brief account:

The rugged and isolated Hazara and Swat districts of northern Pakistan were subjected to a magnitude 6.2 earthquake at 12:11 UTC on Dec 28, 1974. The epicentre was located at 35.1 degrees north and 72.9 degrees east. The quake had a shallow focal depth and was followed by numerous aftershocks. An official estimate of the number killed was 5,300 with approximately 17,000 injured. A total of 97,000 were reported affected by the tremor. Most of the destruction was centred around the village of Pattan, located about 100 miles north of the capital city of Islamabad. The village was almost completely destroyed.

The epicental region is characterized by steep-walled narrow canyons and valleys. Most of the population is concentrated along the rivers. Much of the destruction was caused by the numerous landslides and rockfalls which came tumbling down from high above. The main road leading into the area was blocked for about 25 miles by landslides and rockfalls, hampering relief efforts. The government flew in emergency supplies by helicopter until the roads were reopened on Jan 13.

The earthquake, which was felt intensity V in Kabul, Afghanistan, affected some 1,000 square miles of the Indus Valley region. Several nations contributed money and supplies to aid the inhabitants of the stricken area. [Abridged from Earthquake information Bulletin, March-April 1975, Volume 7, Number 2]



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