Bhuj earthquake of January 26, 2001: Effects in the Thar-Nagar Parkar region of Sindh, SE Pakistan

Abstract

The Bhuj Earthquake of January 26, 2001 had devastating effects in India in terms of life and property loss. The epicenter being within 150 km from Pakistan's SE border, shocks were felt over a wide region in Pakistan, resulting in wide-spread damage to buildings and a life toss of around 15 people in the southeastern Sindh province of Pakistan. This paper presents results of a field visit to the That-Nagar Parkar region of SE Pakistan, outlining features related with liquefaction and ground failures as a consequence of the Bhuj Earthquake These include sand blows in the inter-dunal depressions and lateral spreading at the crests and margins of the stable dunes. It has been noticed that a 170 km long belt of about 15 km width at the southern fringes of the Thar desert adjacent to the Great Rann of Kuchchh suffered widespread liquefaction, that resulted in damage to mud houses and cane huts in several villages, including the Tobo village (southeast of Diplo) where 2500 such houses Were completely or partially collapsed. No liquefaction was noticed at Nagar Parkar town (With bedrock as foundation) as well as in the northern parts of the Thar desert (probably due to low water table), and all the damage to buildings in this region was in response to groundshaking. Based on reported damage three isoseismal intensity zone have been identified l) region encompassing parts of the Thar desert including towns/villages of Nagar Parkar, Islamakot, Diplo, Tobo, and Mithi is assigned an intensity of VIII on  MMI scale based on extensive damage to masonry buildings and intensive liquefaction in parts of the region, 2) northern Thar desert, districts of Mirpur Khas, Badin and Hyderabad have been assigned intensity of VII, based on development of crakes and partial collapse to poorly constructed masonry buildings, and 3) region Where buildings escaped damage but experienced swaying in response to ground shaking was assigned intensity VI, including the cities of Karathi and Sukkhar. Tectonic setting of the Thar desert and lower Indus basin underlain by Cretaceous normal faults and close proximity to two seismic zones Kuchchh seismic zone in the southeast and Chaman seismic zone in the west-northwest, suggests that the region is susceptible to earthquake hazards. Further, the region is underlain by a thick cover of recent loose sediments, susceptible to liquefaction and with a capacity to amplify the ground shaking. Installation of a network of seismometers, strong-motion accelerographs and Global Positioning System (GPS) is essential to monitor seismic hazardpotential of the region. Meantime immediate attention is needed towards public awareness about response to seismic hazards, reinforcement of buildings especially schools and development/implementation of building codes in the region.