3.8 Magnitude Earthquake in Sylhet area, Bangladesh -ACaseStudy of School Building Damage

Abstract

A minor earthquake (magnitude 3.8) hits the Sylhet area, Bangladesh at 18:29:21 BST on 07 June 2021. The epicenter of the earthquake is located about 10 km south of Sylhet City Corporation (SCC) area. SCC is located in the most active seismic zones of Bangladesh. A high school building in the SCC area was moderately damaged due to the earthquake. Building damage, geology, and geomorphology of the area were checked by field inspection, image analyses, literature review, and online resources. The building was built on an artificially filled big pond (named Laldighi) with unconsolidated soft soil. The school building was constructed in 2006, and horizontally (N-S direction) and vertically extended in 2018. A series of N-S direction large diagonal and linear cracks were observed in the walls, pillars, floors, and staircases of the building due to the earthquake. Septic tanks and pipelines were located on the south side of the damaged building and were settled down at different rates. In June 2021 total of 9 earthquake of magnitude between 3 and 4 occurred in Bangladesh. Though low magnitude earthquake occurs frequently, usually significant damage, like in case of the above-mentioned earthquake, are not reported. Therefore, we recommended geoscientists, engineering geologists, urban planners, civil engineers, and policymakers to carry out detailed geological studies for sustainable urban and infrastructure development plans.