In 2025 a major earthquake of M 7.0 or larger hit central Myanmar, rupturing up to more than 530 kilometers of the Sagaing Fault. This event contained an unusual supershear rupture over a 450-kilometer section. It released such buttress seismic shock fronts that magnified the shaking hundreds of km away. All of this devastation resulted in widespread building destruction and extensive soil liquefaction, some of which was visible from space.
The complex, steeply geometry of the Sagaing Fault was very important in producing the supershear earthquake. This earthquake ruptured the Rangely fault, which had been considered relatively quiet since the last major rupture in 1839. The speed at which the rupture in the southern branch of the fault traveled has been recorded as high as 5 kilometers per second. By comparison, the northern branch spread much more slowly. Predisposing geological conditions enabled this rupture to accelerate and keep its speed over great stretches of space.
Understanding Supershear Ruptures
Supershear earthquakes are an unusual quake where seismic waves race along at speeds faster than normal earthquake wave fronts. California State University Los Angeles professor Lingsen Meng is a UCLA trained geophysicist. As the senior author of a new paper in the journal Science, he described how important these moments are.
“Supershear earthquakes are like breaking the sound barrier, but in rock,” – Lingsen Meng.
This strange high velocity generates shock fronts. These seismic hot fronts can increase the intensity of seismic shaking up to twice that felt a considerable distance from the epicenter. The research team employed an integrated approach combining global seismic data, satellite radar (InSAR), and optical imagery to reconstruct the rupture dynamics of the 2025 Mandalay earthquake.
The study found that these differences in rock characteristics on either side of the fault interface were key factors in allowing the supershear rupture to occur. The extreme rupture speed observed was a compounded effect of a bimaterial effect and the existence of a favorable energetic ratio. This result underscores that even relatively mature continental faults can misbehave in unexpected ways.
The Impact on Central Myanmar
The 2025 earthquake’s aftershocks brought widespread epidemiological and socioeconomic disruptions throughout central Myanmar. Building collapses dominated the news from many different areas, while soil liquefaction led to widespread infrastructural damage. These effects were so massive that they could be measured from outer space, testimony to the overwhelming scale of destruction local communities are facing on-the-ground.
Researchers have long stressed how important it is to understand these physical conditions to better measure threats from future earthquakes. Professor Meng noted the importance of this research in estimating hazards in fault systems located near densely populated urban areas.
“Understanding the physical conditions that allow a rupture to reach these speeds will help us better estimate future earthquake hazards—especially in fault systems near major cities,” – Lingsen Meng.
Since 1839, stress has been slowly accumulating along the Sagaing Fault. This accumulation played a major role in the severity of the event. This build-up of stress set the stage for a major faulting, and is one reason why the shaking from the earthquake was so destructive.
Geological Insights and Future Implications
The results of this study are not only important for Columbus, their implications reach far into the fields of seismology, and urban planning. The research further clarifies why faults behave the way they do under various conditions. It similarly reminds the communities who reside on or by these dynamic ground shakers to always be prepared.
The phenomena seen during the 2025 Mandalay earthquake remind us that even some of the most studied geological features can still behave in surprising ways. As Professor Meng told the New York Times, this is a reminder of the hiding dangers that can come with continental faults.
“This event reminds us that even well-studied continental faults can behave in unexpected and dangerous ways,” – Lingsen Meng.
Scientists are still pouring over the data from this extraordinary event. Their goal is to have their insights make predictive models and preparedness strategies better ahead of the next big seismic event.