Seismic damage of high-rise buildings in Bangkok caused by soft soil amplification from Mw 6.4 Laos earthquake

Bangkok is considered as a low seismic zone but there is a seismic hazard primarily caused by the presence of thick soft clay deposit in Bangkok which has an ability to amplify the earthquake ground motion by 2-4 times. This effect makes high-rise buildings in Bangkok vulnerable to resonance effects and soil-structure interaction during distant earthquakes. In 2019, a 6.4 Mw earthquake in Laos, located at 700 km from Bangkok, caused noticeable shaking various large and small buildings around Bangkok city. This research evaluates the effect of that earthquake on various buildings located in Bangkok using Modified Mercalli Intensities (MMI) index. Additionally, a case study was conducted in a condominium to evaluate various cracks observed after the earthquake. The vibration characteristics of the building closely matched nearby seismic stations, indicating that long-distance earthquake effects influenced the oscillation between the ground motion and the building response. Since the recorded maximum surface acceleration was low, the earthquake earthquake primarily affected joints between materials with differing structural strength, while the main structure remained intact.