Myanmar Earthquake Mw 7.7 on 28 March 2025: geodynamic and spaceborne DInSAR perspectives

The paper presents the probability of earthquake occurrences and forecasting of earthquake magnitudes size in northeast India, using four stochastic models (Gamma, Lognormal, Weilbull and Log-logistic) and artificial neural networks, respectively considering updated earthquake catalogue of magnitude Mw ≥ 6.0 that occurred from year 1737 to 2015 in the study area. On the basis of past seismicity of the region, the conditional probabilities for the identified seismic source zones (12 sources) have been estimated using their best fit model and respective model parameters for various combinations of elapsed time (T) and time interval (t). It is observed that for elapsed time T=0 years, EBT & Kabaw zone shows highest conditional probability and it reaches 0.7 to 0.91 after about small time interval of 3-6 years (2014-2017; since last earthquake of Mw ≥ 6.0 occurred in the year 2011) for an earthquake magnitude Mw ≥ 6.0.Whereas, Sylhet zone shows lowest value of conditional probability among all twelve seismic source zones and it reaches 0.7 after about large time interval of 48 years (year 2045, since last event of Mw ≥ 6.0 occurred in the year 1999). While for elapsed time up to 2016 from the occurrence of the last earthquake of magnitude Mw ≥ 6.0, the MBT & MCT region shows highest conditional probability among all twelve seismic source zones and it reaches 0.88 to 0.91 after about 6-7 (2022-2023) years and in the same year (2022-2023) Sylhet zone shows lowest conditional probability and it reaches 0.14-0.17. However, we proposed Artificial Neural Network (ANN) technique used to predict the possible magnitude of future earthquake in the identified seismic source zones is based on feedforward backpropagation neural network model with single hidden layer. For conditional probability of earthquake occurrence above 0.8, the neural network gives the magnitude of future earthquake as Mw 6.6 in Churachandpur-Mao fault (CMF) region in the years 2014 to 2017 and for Myanmar Central Basin (MCB) region it gives magnitude of future earthquake as Mw 7.0 in the years 2013 to 2016 and for Eastern Boundary Thrust (EBT) & Kabaw region it gives magnitude of future earthquake as Mw 6.4 in the years 2015-2018. The epicentre of recently occurred 4 January 2016 Manipur earthquake (M 6.7), 13 April 2016 Myanmar earthquake (M 6.9) and the 24 August 2016 Myanmar earthquake (M 6.8) are located in Churachandpur-Mao fault (CMF) region Myanmar Central Basin (MCB) region and EBT & Kabaw region, respectively and that are the identified seismic source zones in the study area which show that the ANN model yields good prediction accuracy.

The 7.7 Mw earthquake that struck the Sagaing region, Myanmar, on March 28, 2025, caused cross-border seismic effects felt as far as Bangkok, Thailand, about 600 km from the epicenter. Although considered a low-seismic-risk area, tremors of intensity IV–V on the Modified Mercalli (MMI) scale produced strong shaking in high-rise buildings and led to the collapse of construction projects in the Chatuchak District. This study examines the relationship between Bangkok’s geotechnical conditions and the dynamic responses of buildings to the 2025 Myanmar earthquake. The qualitative-descriptive method includes literature review, field observations in Sathorn, Silom, and Chatuchak, and comparative analysis with the 2011 Tohoku and 2015 Nepal earthquakes. Results indicate that a 15–30 m thick water-saturated clay layer with a shear wave velocity (Vs30) below 150 m/s and a dominant period of 1.8–2.5 seconds amplified ground motion up to twice the theoretical value. This condition triggered ground–structure resonance, affecting buildings with 15– 25 storeys and deep-pile foundations, as well as flexible structures. The Chatuchak collapse was due to resonance combined with poor construction stability. These findings confirm that long-period waves pose significant risks to delta cities, such as Bangkok, underscoring the need to revise national seismic design standards by incorporating local amplification and long-period effects in soft soil zones.