The earthquake in Myanmar caused greater damage than a “standard” of magnitude 7.7 and its shocks felt unusually strongly even far away.
The Myanmar is collapsing for the earthquake of magnitude 7.7 which hit the region on March 28, 2025: thousands of people under the rubble, full hospitals and risk of spreading infections between the population.
The USGS PAGER (Geological Service United States – Rapid evaluation of global earthquakes for reply) estimates a 67% probability of more than 10,000 victims. In addition to the impacts on buildings, damage to airports, roads and bridges occurred, including the collapse of the control tower at Naypyitaw airport, hindering the efforts of the rescuers.
understand to prevent. After destructive events of this type, there is an apparent contradiction between the need for immediate humanitarian assistance and the desire for seismologists to quickly understand what really happened. These are not in contrast needs: Each great earthquake, in fact, helps us to understand what the processes that determine these dangers and teaches us to act to prevent damage in the future.
Questions. At the moment geologists and seismologists ask some fundamental questions: how long the breakage of the fault? How quickly the fracture has developed? Which are The implications in terms of damage? For now we have only preliminary information that will probably change during the research, but some elements are now certain.
Great earthquake. It should be remembered that while earthquakes are often represented as points on the maps, which represent the place where the rupture began (the epicenter), in reality they derive from the sliding on surfaces inside the earth’s crust. Kyle Bradley of the Earth Observatory of Singapore explains: «For a small earthquake, a point is usually a good representation. However, for a very large earthquake, the break could be tens, hundreds or even more than a thousand kilometers long. When considering the impacts of earthquakes, it therefore becomes important to consider not only the distance from the epicenter, but also the length from the fault surface that has moved. A building located hundreds of kilometers away from the epicenter could still be directly above the fault that has moved».
The evolution of hypotheses. The sagaing fault, which broke into Myanmar, is well mapped on the surface. However, since there are Very few scientific operating tools in Myanmarit was difficult to understand how much part of the fault actually broke during the earthquake of 28 March 2025. The initial estimates of the shining of the fault were calculated using only readings of distant seismometers.
These data have made it possible to measure the magnitude of the earthquake, but gave misleading results on the breakdown of the fault.
As Judith Hubbar explains, geologist at Cornell University: «The first USGS breakdown model estimated up to ~ 5 meters of slipping on a span of ~ 200 kilometers, which had been from ~ 22.5 ° n to 20.5 ° n, for a duration of about 90 seconds. This number was consistent with a break that spread through the ground at a speed of ~ 2 kilometers per second (about six times faster than the speed of sound in the air). On the basis of past earthquakes, we can expect a 7.7 magnitude earthquake to occur from the breakdown of a section of fault about 200 kilometers long, so this number would have made sense. If it were not that seismological observations of the last hours suggest that the break has been longer. At the moment the model has been updated to ~ 6.5 meters of maximum lateral slip and 20 km deep on a long fault ~ 270 kilometers, but a series of other preliminary results suggest an even longer break, so much so that we talk about A break of over 550 km».
What are “Supershear” earthquakes? The duration of the earthquake, measured through the seismograms, allows to estimate the speed of the earthquake propagation. A break of the fault longer than 250 km would imply a speed higher than the norm and in this case we speak of an earthquake from “supershear”. This means that A fault breaks at a speed higher than the propagation speed of the S waves (wave waves) in the surrounding rock. These events, although rare, can generate waves that are similar to sonic booms.
Zhe Jia, of the University of Texas, explains: “The earthquakes” Supershear “tend to generate more intense shocks on a wider area, due to theHigh speed of fracture propagation that concentrates seismic energy. This effect can cause Significantly greater damage than a “standard” earthquake of magnitude 7.7with a potential impact on community located hundreds of kilometers from the epicenter “. This phenomenon may have caused particularly intense shocks in the areas south of the epicenter and could explain the Unusually strong shocks recorded in Bangkok. To confirm this hypothesis, specific shocks computer will be needed, which can be studied in the coming months ».
Long -range. Although Bangkok is about 1,000 kilometers south of the epicenter, the southern end of the fracture was much closer, about 600 kilometers, that’s why it is thought that this is the length of the fault that moved.
However, it is also possible that the damage to Bangkok has been aggravated by soil conditions. The amplification of seismic waves, which occurs when they cross soft sediments, can intensify the shocks. This phenomenon occurred in Mexico City in 1985, due to an earthquake that occurred 350 kilometers away.
How will it continue? The remote effects of the great earthquakes can be surprising. An interesting observation, emerged from the analysis of the Catalog of earthquakes of Thailand, concerns The increase in low magnitude seismic activity along the border between myanmar and northern Thailand. This region, located About 200 kilometers from the sagaing fault and part of the Shan plateau, is characterized by a series fault spent curves.
The sudden increase in small seismic eventsmainly of magnitude 2-3, with an event of magnitude 4.1, is a common phenomenon after great earthquakes. However, the distribution of these events on such a vast area remains a mystery, which will require further investigations on the dynamics of the main fracture.
