Strong intensity, shallow concussion in the densely populated area and liquefied soil can contribute to the heavy damage caused by earthquakes on March 28 in Myanmar.
People standing next to a building collapsed in Mandalay on March 28 after the 7.7 -degree earthquake. Image: STR
A strong 7.7 -degree earthquake attacked in Central Myanmar, vibrating Mandalay, the second largest city of this country and many neighboring countries, including China, Thailand, and Vietnam. The earthquake occurred at 12h50 on March 28 (13h20 hours in Hanoi) at a depth of about 10 km, considered as agricultural, according to the US Geological Survey (USGS). 12 minutes later, a 6.7 -degree strong earthquake at the same depth in the south of the first earthquake. At the end of the day, 9 smaller earthquakes from 4.4 to 4.9 degrees also appeared in the region, according to Live Science.
At least 144 people died in the earthquake and 732 injured. A monastery and many buildings collapsed in Myanmar. In Bangkok, at least 10 people were killed and a 33 -storey skyscraper under construction. Thai authorities informed 16 injured people and 101 missing people. Although Bangkok is far from the fault in Myanmar, “this is a big earthquake and it is not surprising that it can feel it at such a distance,” said Gregory Beroza, a geophysical professor at Stanford University.
The earthquakes are near Sagaing broken from North to South Myanmar, stretching nearly 1,600 towards the Andaman Sea. The earthquakes that take place in this fault are called horizontal sliding coves, in which a mass of soil moves across another soil block on the other side of the fault, similar to San Andreas fault in California, USA.
Sagaing fault runs along Myanmar. Image: Lyell Collection
Myanmar is located south of the Himalaya range as an area that often has earthquakes and is famous for big earthquakes, according to Ben van der pluijm, honorary professor of geology at the University of Michigan. The Indian continent is located on the Indian array. The Indian array has moved north in about 100 million years. But about 40 million years ago, the Indian array came into contact with the Asian segment and continued to move in the north, stabbing into the Eurasian segment. Over the millions of years, that collision contributed to creating the Himalayas.
Even today, the Indian segment continues to move, accumulates energy and releases in the form of earthquake like an earthquake in Myanmar, according to Van der pluijm. The earthquake of 7.7 was so large that it was not surprising if the ground was skewed a few meters horizontally.
The devastation of the earthquake is not only the result from the intensity but also from its position and depth. Despite the smaller intensity, shallow earthquakes can cause violent vibration on the ground, threatening infrastructure in densely populated areas. The earthquake in Myanmar has all dangerous factors. It has a strong intensity with shallow concussion and occurs in a crowded residential area with many buildings and works that are easily affected.
Due to the shallow earthquakes, they can match the earthquake of 7.8 and 7.5 degrees Türkiye’s devastation in 2023, causing casualties and damage on a large scale, according to Jeffrey Park, a professor of Earth and the planet science specializing in earthquakes and earth structures at Yale University. “We predict the number of casualties and damage from this earthquake will be similar because this is a shallow earthquake in a crowded residential area,” Park said.
Since 1900, the area has recorded 6 horizontal landscape 7 degrees or more within a radius of 250 km around the earthquake on March 28. The closest was a 7 -degree earthquake in January 1990, causing 32 buildings to collapse. Another 7.9 -degree earthquake used to shake the southern area of the latest earthquake in February 1912.
The areas with thick soils tend to liquefy in the earthquake. The process is the dead interaction between the seismic and sediment, temporarily causing the soil to operate like sandy sand. The previous earthquakes in the area caused landslides and liquefied, can contribute to the destruction of the latest earthquake.