In this study, seismic deaggregation analysis is applied for Chiang Mai and Chiang Rai in Northern Thailand to assess the combined effect of all magnitudes and distances on the probability of exceeding a given ground motion level. Deaggregation of peak ground acceleration and spectral acceleration at 1 s at different return periods are derived. From comparing the hazard maps from different major cities, it could be concluded that both cities have similar hazard estimates for considered return periods but by deaggregating the hazard, the controlling earthquake scenarios are different, partly du Authors: Teraphan,,Ornthammarath;Pennung,,Warnitchai. Presented at TSER2023.