The Pattan (Pakistan) earthquake of 28 December 1974: field observations

Introduction In the early evening of 28 December 1974, a magnitude 6.0 ( m b USGS) earthquake occurred in a remote and mountainous region of northern Pakistan, resulting in loss of life and damage to property. The Pakistani Army Engineers involved in construction and maintenance of the Kara Korum Highway, a one-to two-lane gravel road along the Indus River valley, quickly established an efficient relief operation. Since the highway was damaged and unusable during most of the relief operation, helicopters were used to carry supplies from Besham, at the end of the usable highway, to Pattan, where a hospital camp was set up. Two seismic reconnaissance teams visited the affected area: the first arrived from Tarbela Dam on 1 January 1975, and included one of the authors (Pennington); the second team, with the other three authors (Ambraseys, Lensen and Moinfar) arrived later in January. The following report is based largely on their field studies (Ambraseys et al . 1975; Pennington 1975). The earliest known earthquakes of the Northwest Frontier Provinces (NWFP) As early as the 4th century BC, the region north of the Jhelum was reputed for its destructive earthquakes. Historians who accompanied Alexander the Great on his expedition in Swat allude to such events; they briefly state that as a result of earthquakes in this track of country even the beds of rivers are changed. Alexander must have reached Aornos (modern Pir-sar about 20 km from Besham) late in 327 BC (Stein 1927, 1929; Fig. 3).