Lessons learnt from post-earthquake damage study of Northeast India and Nepal during last ten years: 2021 Assam earthquake, 2020 Mizoram earthquake, 2017 Ambasa earthquake, 2016 Manipur earthquake, 2015 Nepal earthquake, and 2011 Sikkim earthquake. Issue 151 (December 2021) - Halder, Lipika
Abstract: The present paper is exhaustive documentation made from the post-earthquake damage survey conducted to analyse the major reasons for structural failure during six earthquakes, occurred over the last decade in the Northeastern region of the Indian subcontinent. In the beginning, an attempt is made to highlight the seismological reasons for the vulnerability of this region. Further, it presents the available building typology of this region and makes an attempt to analyse the reasons for the damage/collapse of each type of building. The reasons are primarily found to be lacking in the implementation of many well-known design guidelines, which are available in the design codes/well-accepted design documents. This document may be of immense help to the practising engineer to underline and visualise many common yet neglected issues during the design and construction of structures. This may, in turn, help to reduce the vulnerability of the structures of earthquake-prone developing countries. Highlights: 1. This paper presents detailed documentation of the damages or collapsed buildings/dwelling units in the Northeastern region of the Indian subcontinent and Nepal due to the six seismic events over the decade. 2. Many people of this region belong to very poor socio-economic conditions. In fact, they are not very concerned about the sudden damages which earthquakes may create. 3. Initially, the reason for frequently occurring low to moderate earthquakes is attempted to be explained from the seismological and geological point of view. 4. The typological nature of the structures, buildings, and habitats are discussed in detail to understand and visualize the physical mechanism behind the damage of each type. 5. Along with the detailed case studies, remedial measures are also reiterated, most of which are known by academia but not implemented because of the mindset of civil engineering professionals.