Swiss Seismological Service "The quake was strong - but not surprising"
A magnitude 7.7 earthquake has shaken parts of Thailand and Myanmar. What is known - and what does the event mean from a geological perspective? The Swiss Seismological Service classifies it.
No time? blue News summarizes for you
- The quake came without warning for the population. However, it occurred along an active geological fault that runs north-south through Myanmar.
- The fault lies on the boundary between the Indian and Eurasian plates - a known seismic hazard zone.
- Minutes after the main quake with a magnitude of 7.7, an aftershock with a magnitude of 6.4 occurred - followed by several other smaller quakes.
- The Swiss Seismological Service (SED) explains that early warning systems such as those in Japan or Italy require a very dense network of seismic stations - such a network does not (yet) exist in Southeast Asia.
A strong earthquake with an epicenter in Myanmar has shaken the region of Southeast Asia. blue News asked Paolo Bergamo from the Swiss Seismological Service (SED) how the quake can be scientifically classified - and what it means for global disaster prevention.
The expert emphasizes: "A quake of this magnitude is not unusual for the region."
The epicenter of the quake was located at a depth of around 10-20 kilometers - "it is difficult to determine the exact location as there are only a few measuring stations in the region," says Bergamo.
No omens - but an expected event
The magnitude of the earthquake was so great that the tremors were clearly felt as far away as Bangkok (over 1000 kilometers to the south) and as far away as the Chinese province of Yunnan. At least one building collapsed in Bangkok.
According to Paolo Bergamo from the SED, there were no significant seismic signs before the quake. "There are currently no records of significant seismic activity before the event," he says.
No quake with a magnitude of over 3 was recorded in the region in the previous seven days. However, seismic monitoring on site is not particularly dense. Smaller foreshocks could therefore have gone unnoticed.
Tectonically highly explosive zone
Nevertheless, the quake was not surprising from a geological point of view. According to the earthquake service, quakes of this magnitude are not unusual for the region. Since 1900, there have been at least six other quakes with a magnitude of 7 or more.
In January 1990, for example, a quake with a magnitude of 7.0 caused 32 buildings to collapse. In 1912, a quake with a magnitude of 7.9 occurred south of the current epicenter.
The quake occurred along the Sagaing Fault, a major geological fault that runs north-south through Myanmar. This fault is part of a complex system at the boundary of the Indian and Eurasian plates - one of the most geologically active zones in Asia.
Only a few minutes after the main quake, an aftershock with a magnitude of 6.4 occurred about 30 kilometers to the south, followed an hour later by three more smaller quakes with a magnitude of 4.5 about 70 kilometers north of the epicenter. "Further aftershocks are also to be expected in the coming days and weeks," explains Paolo Bergamo. These could cause further damage.
Early warning systems? Not a thing
There are currently no earthquake early warning systems in Thailand and Myanmar, such as those used in Japan, Mexico, Italy, Turkey, Romania, China and Taiwan. Such systems require a dense network of seismic stations close to active faults - this infrastructure is lacking in South East Asia.
After the 2004 tsunami, which killed almost 250,000 people, a tsunami warning system was set up for Indonesia and other affected areas - but this differs technically from an earthquake early warning system.
The latter uses the time delay between the first, less damaging waves (P-waves) and the destructive waves (S-waves) to send out warnings. For every 6 kilometers from the epicentre, there is about one second of warning time - provided the system works well.
Quake felt as far away as China
The force of the quake was enormous: it was even clearly felt in Bangkok, around 1000 kilometers south of the epicentre, where a building collapsed. Damage was also reported from the southern Chinese province of Yunnan.
Although the Swiss Seismological Service does not directly analyze local data from Myanmar, the relevance of significant events such as this one is checked - and contact is made with the Swiss Humanitarian Aid Unit (SHA) if necessary.
This is part of Swiss Humanitarian Aid and coordinates possible support services abroad.
What lessons for Switzerland?
Even though the quake occurred in South East Asia, the findings are also relevant for Central Europe. "Events like this could be an impetus to further intensify risk reduction measures - for example in construction standards or in the preparation of civil protection," says Paolo Bergamo.
Precise earthquake forecasting is still not possible. However, operational earthquake forecasting, in which probabilities are assessed, is the subject of current research - including in Switzerland.
The editor wrote this article with the help of AI.
