Liquefaction hazard mapping by liquefaction potential index for Dhaka City, Bangladesh Md. Zillur Rahman a , Sumi Siddiqua a, ⁎, A.S.M. Maksud Kamal b a School of Engineering, The University of British Columbia, Okanagan Campus, Kelowna, BC V1V 1V7, Canada b Department of Disaster Science and Management, University of Dhaka, Dhaka 1000, Bangladesh abstract article info Article history: Received 14 June 2014 Received in revised form 4 November 2014 Accepted 17 January 2015 Available online 23 January 2015 Keywords: Standard Penetration Test Simplified Procedure Liquefaction potential index Cumulative frequency distribution Liquefaction hazard map Dhaka City Preparation of liquefaction hazard map of prone areas has high importance for decision makers or site planners to reduce loss of lives. In this study, liquefaction hazard map of Dhaka City was prepared using liquefaction potential index (LPI) and cumulative frequency distribution of LPI of surface geological units, which is an excellent ap- proach to evaluate the liquefaction hazard quantitatively and spatially. LPI values were calculated using Simpli- fied Procedure of liquefaction potential assessment for 53 Standard Penetration Test (SPT) profiles conducted in different surface geological units of the city. The LPI values of the city varied from 0 to 19.33 having very low to very high liquefaction hazard. The hazard of each unit was also defined by cumulative frequency at LPI = 5 which may be evaluated as the threshold for observation effects of liquefaction on surface. The geological units of the city were grouped into three liquefaction hazard zones, i.e., Zone 1, Zone 2 and Zone 3 based on cumulative fre- quency. The hazard map indicates that 8%, 50% and 72% of Zone 1, Zone 2 and Zone 3, respectively, will show sur- face manifestation of liquefaction for an earthquake scenario having a magnitude of 7.0 (M w ) and a peak ground acceleration of 0.15 g. © 2015 Elsevier B.V. All rights reserved. 1. Introduction A number of studies on liquefaction and liquefaction-induced ground failures were performed by many researchers after the devastat- ing earthquakes of Alaska and Niigata which occurred in 1964, where slope, bridge and foundation failures were observed as a result of soil liquefaction (Sonmez and Gokceoglu, 2005). Historical incidents of earthquakes indicate that destructive earthquakes may occur around Bangladesh (Bilham and England, 2001; Ambraseys and Bilham, 2003; Bilham and Wallace, 2005). The occurred historical earthquakes in Bangladesh and NE India are listed in Table 1. Some of these earth- quakes such as the 1885 Bengal Earthquake (Middlemiss, 1885), 1897 Great Indian Earthquake (Oldham, 1899) and 1918 Srimangal Earth- quake (Stuart, 1920), caused serious damage to buildings and other in- frastructures of Bangladesh. Although significant damage was reported in Dhaka City during the 1897 Great Indian Earthquake and 1885 Bengal Earthquake, there was no document on the extent of the damage in Dhaka during the 1918 Srimangal Earthquake. Therefore, moderate to large earthquake magnitudes may occur in this region due to continuing tectonic deformation along the plate boundaries and active faults (CDMP, 2009). When earthquakes hit the developing countries, millions of fatalities may occur (Bilham, 2009). Such earthquakes may also in- crease in damage to buildings, bridges, industrial and port facilities, etc. The soil liquefaction is one of the major reasons for the increase in damage to infrastructures. Earthquake induced liquefaction phenomena have been recorded and developed in many parts of the world (Seed and Idriss, 1971, 1982; Iwasaki et al., 1978, 1982; Seed et al., 1984, 1985; Robertson and Wride, 1997; Youd and Idriss, 2001; Youd et al., 2001; Seed et al., 2003). The methods of liquefaction susceptibility analysis and mapping have further been modified, improved, calibrated and validated by many researchers (Chen and Juang, 2000; Juang et al., 2003, 2008, 2009; Sonmez, 2003; Sonmez and Gokceoglu, 2005; Sonmez et al., 2008; Lee et al., 2004; Papathanassiou et al., 2005; Cox et al., 2007; Papathanassiou, 2008; Holzer, 2008; Jha and Suzuki, 2009; Heidari and Andrus, 2010; Kang et al., 2014; Palacios et al., 2014 and others). Dhaka City is located close to seismically active zone. The eastern, west- ern, southeastern parts of the city are covered by the Holocene sand, silty sand, silty clay, sandy- and clayey-silt up to more than 20 m depth from the ground surface. However, there are few studies about the potential of liquefaction in Dhaka City, and a limited number of lit- erature is available on seismically induced liquefaction hazard assess- ment of the city. Therefore, in this study an attempt was taken to prepare a seismically induced liquefaction hazard map of Dhaka City Corporation area. The objectives of this research were to compute lique- faction potential of the subsurface geological materials of Dhaka City using Simplified Procedure to estimate liquefaction potential index Engineering Geology 188 (2015) 137–147 ⁎ Corresponding author. E-mail address: sumi.siddiqua@ubc.ca (S. Siddiqua). http://dx.doi.org/10.1016/j.enggeo.2015.01.012 0013-7952/© 2015 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Engineering Geology journal homepage: www.elsevier.com/locate/enggeo