Seismic Vulnerability Assessment of Pakistan Unreinforced Masonry Buildings at a National Scale

Abstract

Seismic activity in Pakistan has generally been concentrated in the northern part of the country, the northern and southwestern parts of Balochistan Province, and the coastal areas of Sindh Province, as reflected in the Pakistan seismic zoning map (Figure 1). In the last one hundred years alone, the country has experienced the M 7.5 1935 Quetta earthquake (30,000 fatalities), M 8.0 1945 Makran Coast earthquake (4,000 fatalities), M 6.2 1974 northern Pakistan earthquake (5,300 fatalities), and M 7.6 2005 Pakistan earthquake (86,000 fatalities) (U.S. Geological Sur vey historic worldwide earthquakes, http://earthquake.usgs.gov/regional/world/historical_country.php#pakistan). Pakistan unreinforced masonry (URM) buildings suffered extensive damage in the 2005 Pakistan earthquake (Rossetto and Peiris 2009) and other historical earthquakes; however, URM construction continues to be prevalent in Pakistan primarily due to the availability of raw materials and the continued use of traditional construction practices. Pakistan has experienced high human and economic losses in previous earthquakes, and similar or even worse statistics can be expected in future earthquakes, in part due to the existence of a potentially vulnerable URM building stock, the seismic vulnerability of which must be assessed to minimize future losses.