Kyaukkyan Fault

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The Kyaukkyan Fault is a large, active strike-slip fault in Southeast Asia. It runs about 510 kilometers from Shan State in Myanmar toward Thailand, through the Shan hills and roughly parallel to the better-known Sagaing Fault. The fault is highly segmented, with many branches and basins created by releasing bends and local extension. The overall slip rate is about 1 millimeter per year.

The northern part extends about 160 kilometers north of Taunggyi and ends east of Mandalay. It is named for the Myint Nge River, which is offset by the fault. In 1912, this segment ruptured over about 160 kilometers and produced a major earthquake of magnitude about 7.7. The area around this segment forms a transtensional basin about 50 by 100 kilometers, bounded by the Taunggyi and Pindaya normal faults. Prominent fault scarps are visible, with the Pindaya fault scarp about 350 meters high and the Taunggyi scarp around 400 meters.

Near Inle Lake, movement on the Taunggyi Fault has tilted the blocks so the eastern side is deeper than the western side. The Salween River segment shows about 5.4 kilometers of offset, creating another transtensional basin along the river. The Mae Ping Fault connects with the Kyaukkyan Fault at this region.

Beyond this, the Kyaukkyan Fault continues for another roughly 170 kilometers, crossing the Myanmar–Thailand border and ending north of Bangkok. Large earthquakes have been rare since 1912, but the Shan Plateau remains seismically active and at risk. Moderate earthquakes were recorded in 1975 and 1985, and researchers have identified evidence of earthquakes along the Kyaukkyan Fault dating to about 1,260 and 4,660 years ago. More recent regional earthquakes include the 1988 Yunnan–Shan event and the 2011 Tarlay event. Estimates for possible future large earthquakes on this fault range from about magnitude 6.8 to 8.4.