The Sagaing earthquake caused the Sagaing fault line to rupture up to 500 kilometers, and signs of fault movement at supersonic speeds were found, which is very rare. Large earthquakes of magnitude 7 and above can return in more than 100 years

Yangon July 9 A new research study shows that the magnitude 7.7 Sagaing earthquake that hit central Myanmar on March 28, 2025, did not only shake the Sagaing and Mandalay regions, but also caused damage to about 500 kilometers along the Sagaing fault line. The earthquake killed thousands of people, injured more than 11,000, destroyed homes, Roads, bridges and infrastructure were heavily damaged. According to the researchers, the damage was caused by a very long fault along the Sagaing fault line that ruptured at high speed near the surface. The researchers used satellite images, They studied ground motion during earthquakes using InSAR and Pixel Offset Tracking techniques. The results showed that the fault rupture was about 500 km long, making it one of the longest strike-slip earthquakes recorded in the world. According to the study, the ground moved up to a maximum of 4.6 meters due to the earthquake, and in normal large earthquakes, the movement on the surface of the ground is less than the underground, but this did not happen in this earthquake, and the fault movement reached the surface in full. Therefore, towns and villages Transportation and infrastructure were directly affected, causing severe damage to people and property, researchers said. According to researchers, the Sagaing Fault is a mature fault that has existed for millions of years and has experienced at least 9 earthquakes of magnitude 7 or higher since 1900. It states that ruptures in faults can continue to propagate very quickly with few barriers. A particular finding of the study is that the southern part of the fault may have ruptured faster than the seismic waves (supershear). This is a rare phenomenon where the speed of the fault ruptures even faster than the speed of the seismic wave, and the researchers say that it can make earthquakes more intense, like a sonic boom caused by an aircraft traveling at the speed of sound.Explained. However, researchers have yet to confirm the phenomenon, and only consider the evidence to suggest that it may have occurred. Their analysis was the low number of aftershocks; It is based on fault shape correction and energy release pattern. According to the researchers, the fault started rupturing from the north and continued to propagate southward within 70 to 90 seconds, and during the first 100 kilometers, it probably shifted to a speed faster than the seismic wave in the south. In addition, it was found that this earthquake ruptured through the fault section between the site of the 2012 magnitude 6.8 earthquake and the site of the 1930 magnitude 7.5 earthquake, which had not experienced major earthquakes for many years. In this section, the researchers concluded that decades of accumulated pressure in the earth could have caused this very long fault rupture. Coulomb stress calculations show that changes in stress on one fault segment encourage further fault segments to rupture, allowing the seismic fault to propagate continuously for up to 500 km. That length is nearly twice as long as previous estimates for a magnitude 7.7 earthquake. The researchers estimated that earthquakes of magnitude 7 or higher in the now ruptured parts of the Sagaing Fault could occur again, on average, once every 104 to 131 years. According to the research team, the findings will make earthquake hazard predictions in Myanmar and Southeast Asia more accurate, as well as provide important scientific evidence for building infrastructure along the Sagaing fault line and improving earthquake resilience. Photo: On March 28, 2025, the main roads in Mandalay were destroyed by the Sagaing earthquake. (Myanmar's deadliest earthquake results in 500 km rupture and signs of a rare supershear break.) The post The Sagaing earthquake caused the Sagaing fault to rupture up to 500 km, and signs of extremely rare supersonic fault movement were found. Major earthquakes of magnitude 7 and above may return in more than 100 years appeared first on Khit Thit Media.