ASSESSING LIQUEFACTION RISK AT LHOKSEUMAWE BEACH: IMPACT OF THE 2004 ANDAMAN AND 2016 PIDIE JAYA EARTHQUAKES

Abstract

This paper presents a study of liquefaction in Lhokseumawe, Indonesia, a topic of urgent importance due to the 2004 Andaman Earthquake (Mw 9.2) and the 2016 Pidie Jaya Earthquake (M_w 6.5). Evaluations of liquefaction potential were conducted in conjunction with particle size distribution analyses and data collected from three Cone Penetration Test (CPT) and three Standard Penetration Test (SPT) locations, which assessed the engineering characteristics and geological conditions of the area. Latitude and longitude coordinates from the sites of the hand-bore, SPT, and CPT tests were utilised to determine the peak ground acceleration (PGA) values associated with these two significant earthquakes. The analysis of liquefaction potential in Lhokseumawe, employing SPT and CPT data, utilised semi-empirical methods. The distribution of soil particle sizes played a crucial role in determining the liquefaction potential. The findings indicate that the study area is primarily composed of poorly graded sand (SP) and well-graded sand (SW). Potential liquefaction sites were generally observed at a depth of 1 meter; however, significant liquefaction potential was also identified at depths of 15 and 18 meters below the surface. Overall, the results of this study emphasise the crucial importance of conducting preliminary investigations into soil liquefaction before commencing construction activities.