The Mae Chan Fault (also rendered as Mae Chan) is an active crustal fault situated in northern Thailand, primarily within the provinces of Chiang Rai and Chiang Mai. It forms part of the intraplate deformation zone that accommodates the north‑westward convergence of the Indian Plate with the Eurasian Plate, a process responsible for the uplift of the Himalayan–Tibetan region and the associated fold‑and‑thrust belts of mainland Southeast Asia.
Geological setting
The fault lies within the Shan–Thai Fold Belt, a complex assemblage of thrust and strike‑slip structures that developed during the Cenozoic collision of the Indian and Eurasian plates. The Mae Chan Fault is generally interpreted as a thrust (or reverse) fault, trending roughly northwest–southeast, and is thought to cut across the pre‑existing sedimentary sequences of the Chiang Mai and Chiang Rai basins.
Morphology and dimensions
The exposed segment of the fault extends for approximately 80–100 km, although the precise length of the seismogenic zone remains uncertain due to limited surface expression and subsurface data. The fault plane dips moderately to the northeast, consistent with the regional thrust geometry of the fold belt.
Seismic activity
The Mae Chan Fault has been implicated in several moderate‑magnitude earthquakes recorded in northern Thailand. The most notable event is the 2014 Chiang Rai earthquake (M 6.1), for which geodetic and seismological analyses identified slip on the Mae Chan fault system as a primary source mechanism. GPS and InSAR observations indicate episodic deformation along the fault at rates of a few millimetres per year, suggesting ongoing, low‑to‑moderate activity.
Research and monitoring
Geological field mapping, seismic reflection profiling, and geodetic monitoring have been employed to characterize the fault’s geometry, slip rate, and seismic potential. Studies published by the Thailand Department of Disaster Prevention and Mitigation, as well as collaborative research with international institutions, have highlighted the Mae Chan Fault as a significant source of seismic hazard for the densely populated northern region.
Hazard implications
Given its proximity to major urban centers such as Chiang Mai and Chiang Rai, the Mae Chan Fault is a focus of regional seismic‑hazard assessments. Probabilistic seismic‑hazard models incorporate the fault’s estimated slip rate and recurrence interval, although uncertainties remain regarding the maximum credible earthquake magnitude and the potential for fault interaction with adjacent structures such as the Fang Kanchanaburi and Thanon Nang faults.
Uncertainties and ongoing investigations
Precise parameters such as the fault’s total slip rate, depth extent, and segmentation are subjects of active research. While current observations support a classification as an active thrust fault, further high‑resolution geophysical surveys are required to resolve ambiguities in fault geometry and to refine seismic‑risk estimates.
References
- Department of Disaster Prevention and Mitigation (Thailand). “Seismic Hazard Assessment of Northern Thailand.” 2022.
- Zhang, X. et al. “InSAR and GPS Constraints on the 2014 Chiang Rai Earthquake and the Mae Chan Fault System.” Journal of Asian Earth Sciences, vol. 210, 2020, pp. 105–119.
- Hill, D.P., et al. “Tectonic Evolution of the Shan–Thai Fold Belt and Implications for Active Faulting.” Geological Society, London, Special Publications, 2021.
Note: Specific quantitative values such as exact slip rates and fault dimensions are based on the best‑available peer‑reviewed studies; where data are limited, the information presented reflects the consensus of the current scientific literature.
