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2025 Sagaing earthquake: Difference between revisions
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A 1,400-kilometer transform fault known as the [[Sagaing Fault]] traverses Myanmar, linking the Andaman spreading center to a collision zone in the north. This fault serves as the boundary between the Burma and Sunda plates, which slide past each other at a rate of 18–49 mm (0.71–1.93 in) per year. It is the largest and most active source of earthquakes in Myanmar, passing through or near major cities such as Yangon, Naypyidaw, and Mandalay. Significant and destructive earthquakes along the Sagaing Fault have occurred in May and December 1930 (Ms 7.3 & 7.5), 1931 (Ms 7.5), 1946 (Mw 7.3 & 7.7), 1956 (Ms 7.0), 1991 (Mw 6.9), and 2012 (Mw 6.9). Earthquake magnitudes along the Sagaing Fault range from Mw 7.0 to 8.0, with recurrence intervals varying by location along the fault. The southern segments, which ruptured in 1930, have return periods estimated at 100–150 years based on paleoseismological studies. | A 1,400-kilometer transform fault known as the [[Sagaing Fault]] traverses Myanmar, linking the Andaman spreading center to a collision zone in the north. This fault serves as the boundary between the Burma and Sunda plates, which slide past each other at a rate of 18–49 mm (0.71–1.93 in) per year. It is the largest and most active source of earthquakes in Myanmar, passing through or near major cities such as Yangon, Naypyidaw, and Mandalay. Significant and destructive earthquakes along the Sagaing Fault have occurred in May and December 1930 (Ms 7.3 & 7.5), 1931 (Ms 7.5), 1946 (Mw 7.3 & 7.7), 1956 (Ms 7.0), 1991 (Mw 6.9), and 2012 (Mw 6.9). Earthquake magnitudes along the Sagaing Fault range from Mw 7.0 to 8.0, with recurrence intervals varying by location along the fault. The southern segments, which ruptured in 1930, have return periods estimated at 100–150 years based on paleoseismological studies. | ||
Destructive earthquakes have impacted Myanmar for centuries, but academic research on these events has been limited. Consequently, many earthquakes in the region, including significant surface-rupturing events, remain poorly understood. One notable event was a large Mw 8.5–8.8 earthquake in 1762, which ruptured a segment of the Sunda megathrust off the Rakhine coast. This earthquake is believed to have resulted from the Indian plate subducting beneath the Burma plate along the megathrust. Additionally, remnants of the subducted Indian plate beneath central Myanmar can trigger intraslab earthquakes, such as the 1975 Bagan earthquake, which was caused by reverse faulting within the Indian plate at an intermediate depth of 120 km (75 mi). | |||
The earthquake also had repercussions in Thailand, particularly affecting the Bangkok region, located approximately 1,000 kilometers from the epicenter. The geology of Bangkok, characterized by a top layer of soft marine clay, makes its high-rises susceptible to distant, powerful earthquakes. The pervasive clay layer amplifies long-period ground motion, potentially matching the resonant frequency of tall buildings as they sway. As a result, occupants in Bangkok have frequently experienced effects from earthquakes occurring hundreds or even thousands of kilometers away. Research led by Pennung Warnitchai from the Asian Institute of Technology previously identified the Sagaing Fault as a significant risk factor, particularly if a magnitude-8.0 earthquake were to occur in the Andaman Sea, just 400 km from the city, posing a threat of future disaster. To mitigate catastrophic impacts on skyscrapers, basic seismic considerations were only incorporated into the building code in 2007, leaving older structures particularly vulnerable. | |||
== References == | == References == | ||
{{Reflist}} | {{Reflist}} | ||