Tian Li, Xiaodong Song
On March 28, 2025, a large earthquake struck central Myanmar and caused massive damage and casualties. The magnitude of the mainshock is a fundamental parameter that both the general public and scientific communities are concerned about. The coda moment magnitude (Mwo) is a new and reliable method for determining the magnitude of large earthquakes, using more than 10 hours of long-period coda waves. We determined the Mwo moment magnitude (with one standard error) to be 7.86 ± 0.025 for the Myanmar earthquake, which is generally larger than the previous reports. The determination includes a small correction (0.017) from our systematic evaluation for smaller earthquakes Mw < 8.3. The difference between the Mwo of the 2008 Wenchuan earthquake and that of the Myanmar earthquake is 0.15 ± 0.030, which is consistent with the difference from the Global Centroid-Moment-Tensor (0.16).