Far‐Field Response of High‐Rise Buildings in Bangkok Based on Public Videos During the 2025 Mw 7.7 Myanmar Earthquake

The 2025 Mw 7.7 Mandalay, Myanmar earthquake caused structural and nonstructural damage to high‐rise buildings in Bangkok, over 1000 km from the epicenter, while low‐rise structures remained unaffected, a selective impact not expected from such a distant source. Because of the limited availability of building instrumentation data in Bangkok, this study analyzed publicly available videos as an alternative data source to estimate building response through water spillage analysis and pixel displacement tracking. To our knowledge, this is the first characterization of the far‐field, basin‐resonance response of a large set of high‐rise buildings from public video. The natural periods of 28 buildings, estimated at 2.8–6.9 s, closely match the 3–7 s long‐period ground motions amplified by Bangkok's deep basin. Despite the low amplitude of recorded ground accelerations, resonant conditions, combined with extended surface wave duration and low building damping, allowed displacement amplitudes to accumulate over multiple cycles, explaining the selective response of high‐rise buildings. A video‐based strong motion period‐height relationship ( T = 0.0261H) is derived, yielding periods about 30% longer than the Thai seismic code formula, which is based on ambient conditions, and the observed drift ratios increase with velocity response spectral amplitude at each building's period. The complete collapse of a 33‐story building under construction is also analyzed, with an estimated period of 4.3 s before the collapse and a drift ratio exceeding 2%, indicating that factors beyond resonance contributed to the failure. These findings demonstrate that video‐based methods can characterize building response where seismic instrumentation is limited, with implications for the seismic design of high‐rise buildings in basin cities exposed to distant large earthquakes.