Myanmar

Myanmar occupies one of Southeast Asia's most seismically complex positions, with active [[subduction-zone]] systems on its western margin and a major continental strike-slip fault running through the country's centre. The Sagaing Fault is a right-lateral strike-slip fault more than 1,200 kilometres long that runs approximately north-south through central Myanmar from the Andaman Sea to the Eastern Himalayan syntaxis near the Bangladesh-India border. This fault accommodates approximately 18–20 millimetres per year of slip — comparable to the San Andreas Fault — making it one of the world's most dangerous active faults. In western Myanmar, the Indo-Burman Ranges represent a fold-and-thrust belt above the active [[subduction-zone]] where the Indian Plate descends eastward beneath the Burma Microplate along the Sunda Arc system. A separate subduction zone in the east, the Shan Scarp fault system, adds additional complexity.

Myanmar's earthquake history is extensive and destructive. The 1930 Pegu earthquake (magnitude 7.3) killed approximately 550 people. The 1956 Sagaing earthquake (magnitude 7.0) killed over 100. The 1975 Pagan earthquake (magnitude 6.5) caused widespread damage to the ancient temples of Bagan, with over 2,000 pagodas damaged. The 2011 Tarlay earthquake (magnitude 6.9) in Shan State killed over 70 people. The 2016 earthquake sequence near Mawlaik (magnitude 6.8) caused casualties and infrastructure damage. More significantly, geological and paleoseismic studies of the Sagaing Fault have identified evidence for prehistoric great earthquakes of magnitude 7.5–8.0 with recurrence intervals of a few hundred years, suggesting that much of the accumulated strain on the fault has not yet been released instrumentally. The capital Naypyidaw and former capital Yangon both face significant seismic hazard from the Sagaing system.

The tectonic framework of Myanmar reflects its position at a major transition in the regional plate tectonic system. The Indian Plate is being subducted eastward beneath the Burma Microplate along the western margin, producing the accretionary prism of the Indo-Burman Ranges and a volcanic arc that includes Mount Popa and other volcanoes in central Myanmar. The trench-parallel component of the oblique subduction is transferred to the Sagaing Fault, creating the right-lateral motion that dominates onshore seismicity. The Andaman Sea to the south is an actively spreading back-arc basin with its own ridge system. The [[epicenter]] distribution of Myanmar earthquakes traces the Sagaing Fault system with remarkable clarity, with additional clusters in the Indo-Burman Ranges and the Andaman Sea. Deep [[seismic-wave]] refraction studies confirm the presence of the subducted Indian Plate slab beneath western Myanmar at depths of 80–120 kilometres.