The magnitude 7 earthquake produced surface ruptures visible 70 years later. Detailed mapping revealed the fault geometry is more complex than thought, affecting seismic hazard estimates.
A Violent Break
On July 16, 1956, a powerful earthquake struck the Sagaing District of central Myanmar. With a moment magnitude of 7.1, the quake caused severe shaking, reaching an intensity of IX (Violent) on the Modified Mercalli scale near its epicenter. The event resulted in the deaths of 38 people and caused significant damage to numerous structures, including the famous Mingun Pagoda. The ground shaking was so intense that it created a visible fracture on the Earth's surface, a feature that geologists can still observe and study today.
This earthquake was not an isolated event but part of a sequence of seismic activity along the Sagaing Fault. This major tectonic boundary is a right-lateral transform fault that runs for over 1,400 kilometers through Myanmar, accommodating the movement between the Indian and Sunda plates. The 1956 rupture occurred on a 60-kilometer segment of the fault just south of where a massive magnitude 7.7 earthquake had ruptured a different segment ten years earlier, in 1946.
A Fault in Plain Sight
The 1956 earthquake was caused by movement along the Sagaing Fault, one of the most significant and active geological structures in Southeast Asia. This fault is the primary boundary between the Burma and Sunda tectonic plates and has a slip rate of approximately 18 to 20 millimeters per year, as measured by GPS data. This rate of movement is comparable to other major transform faults around the world, such as the San Andreas Fault in California.
The surface rupture from the 1956 event shows the fault's behavior. Such ruptures often offset landscape features like stream channels and alluvial fans, allowing scientists to measure the exact amount of horizontal displacement. Detailed field mapping and analysis of satellite imagery reveal the fault's complexity. Instead of a single, clean break, the Sagaing Fault consists of multiple segments and parallel traces. This complex geometry influences how stress accumulates and releases during earthquakes. Understanding these details is important for accurately assessing the seismic hazard for millions of people living in nearby cities, including Mandalay. The persistent scar from 1956 shows the powerful forces at work beneath the surface.
💡Fun Facts
The Sagaing Fault is a massive geological structure, running for more than 1,400 kilometers (870 miles) through the country.
The 1956 earthquake was part of a larger pattern of seismic activity, occurring on a segment just south of the rupture zone of a magnitude 7.7 earthquake in 1946.
The Sagaing Fault's slip rate of 18-20 mm per year is driven by the ongoing collision of the Indian plate with the Eurasian plate.
Heavy damage from the quake was inflicted on several historical monuments, including the Mingun Pagoda, a massive unfinished stupa near Mandalay.
The surface rupture is a geological feature in a rural landscape and is accessible at any time.
Admission
Free.
Accessibility
The fault trace runs through rural and agricultural areas. Access requires overland travel and may involve navigating uneven terrain. It is not a formal tourist site.
The Singu Earthquake of 1956 Surface RuptureMandalay Region, Myanmar