Earthquake Reconnaissance in Bangkok, Thailand, following the 28 March 2025 Mandalay Earthquake

 The 28 March 2025 Mandalay, Myanmar earthquake (Mw 7.7) generated widespread shaking across Thailand, providing a rare opportunity to examine the performance of high‑rise buildings in a deep sedimentary basin located more than 1,000 km from the epicentre. This report presents findings from a New Zealand reconnaissance mission undertaken in Bangkok, focusing on estimating the fundamental period of the deep sedimentary basin, structural and non‑structural damage, building functionality, and site‑specific seismic observations. Ten buildings were investigated through temporary seismic instrumentation, visual inspections, functionality surveys, and discussions with engineers, academics, and property managers.

Across the surveyed buildings, non‑structural elements experienced the most widespread damage, particularly infill walls, ceilings, and façade components. Damage patterns varied with building height and were amplified in structures with vertical irregularities. Structural damage was generally limited, though isolated shear wall failures emphasised the need for improved detailing and construction quality. Functionality impacts were moderate overall, with most essential services recovering within hours to days, but lift outages were extensive, affecting 70% of the buildings visited and constituting the most prolonged barrier to full functionality.

The event highlights the significant influence of basin‑related amplification on distant earthquakes, the critical role of non‑structural performance in maintaining building functionality, and the importance of risk communication in shaping public reuse of buildings. The insights gained from this collaboration between Thai and New Zealand partners advance seismic resilience strategies for high‑rise urban regions exposed to distant ground motions.