On 28 March 2025 a 7.7 earthquake struck the Sagaing Region of Myanmar, with an epicenter close to Mandalay, the country's second-largest city. The strike-slip shock achieved a maximum Modified Mercalli intensity of IX (Violent). It was the most powerful earthquake to strike Myanmar since 1912, and the second deadliest in Myanmar's modern history, surpassed only by upper estimates of the 1930 Bago earthquake. The earthquake caused extensive damage in Myanmar and significant damage in neighboring Thailand. Hundreds of homes were also damaged in Yunnan, China, while more than 300 apartments were affected in Ho Chi Minh City, Vietnam. The earthquake killed as many as 4,940 in Myanmar, 36 in Thailand and 1 in Vietnam. Up to 6,200 people were injured and hundreds more were reported missing, including at a collapsed construction site in Bangkok, whose shallow geology makes it more vulnerable to seismic waves from far away and increases the city's susceptibility to earthquake-related impacts. Authorities in both Myanmar and Thailand declared a state of emergency. As the earthquake struck during Friday prayer hours, collapsing mosques resulted in the deaths of hundreds of Muslims. In addition, more than 670 Buddhist monasteries and 290 pagodas were damaged by the quake. The ongoing civil war in Myanmar has exacerbated the difficulty of disaster relief and info exposure.It is the deadliest earthquake globally since the 2023 Turkey–Syria earthquakes. Even though the south-east Asian nation of Myanmar is a high risk region for earthquakes, neighboring Thailand and China - which were also affected by the quake - are not. The Thai capital, Bangkok, sits more than 1,000km (621 miles) from the epicentre of Friday's earthquake - and yet an unfinished high-rise building in the city was felled by it. Here we will explain what caused this earthquake, and how it was able to have such a powerful effect so far away. What caused the earthquake? The earth's upper layer is split into different sections, called tectonic plates, which are all moving constantly. Some move alongside each other, whilst others are above and below each other. It is this movement that causes earthquakes and volcanoes. Myanmar is considered to be one of the most geologically "active" areas in the world because it sits on top of the convergence of four of these tectonic plates - the Eurasian plate, the Indian plate, the Sunda plate and the Burma microplate. The Himalayas were formed by the Indian plate colliding with the Eurasian plate, and the 2004 Tsunami as a result of the Indian plate moving beneath the Burma microplate. Dr Rebecca Bell, a reader in tectonics at Imperial College London, said that to accommodate all of this motion, faults - cracks in the rock - form which allow tectonic plates to "slither" sideways. There is a major fault called the Sagaing fault, which cuts right through Myanmar north to south and is more than 1,200km (746 miles) long. Early data suggests that the movement that caused Friday's 7.7-magnitude earthquake was a "strike-slip" - where two blocks move horizontally along each other. This aligns with the movement typical of the Sagaing fault. As the plates move past each other, they can become stuck, building friction until it is suddenly released and the earth shifts, causing an earthquake. Why was the earthquake felt so far away? Earthquakes can happen at up to 700km (435 miles) below the surface. This one was just 10km from the surface, making it very shallow. This increases the amount of shaking at the surface. The earthquake was also very large - measuring 7.7 on the moment scale. It produced more energy than the atomic bomb dropped on Hiroshima, according to the US Geological Survey. The size of the quake was because of the type of fault, said Dr Bell. "The straight nature [of the fault] means earthquakes can rupture over large areas - and the larger the area of the fault that slips, the larger the earthquake," she explained. This straight fault also means a lot of the energy can be carried down its length - which extends for 1,200km south towards Thailand. When it comes to why the earth shook so much, scientists believe it is because the quake was a rare "super shear" - meaning energy from the rupture in the earth's crust built up because it was moving faster than seismic waves can travel through the earth. The rupture travelled at a speed of about 5km per second - making it the earthquake equivalent of a supersonic jet. Because the fracture "unzipped" towards the south, it also directed this piled up energy towards the Thai capital, Bangkok, and this is why the earthquake had such an impact so far away. In soft soil - which is what Bangkok is built on - seismic waves (the vibrations of the earth) slow down and build up, getting bigger in size. So, Bangkok's geology would have made the ground shaking more intense. #rescue #scary #earthquake