How the Great Pyramid of Giza has survived earthquakes for thousands of years

For thousands of years, the Great Pyramid of Giza has stood watch over the Egyptian desert, weathering the blazing heat, shifting sands and political empires. But its greatest test has always been below ground. This massive monument has withstood major earthquakes, including a 6.8-magnitude quake in 1847 and a 5.8-magnitude quake in 1992. Now, a groundbreaking study published in the journal Scientific Reports has finally uncovered the secret behind this ancient structure’s incredible earthquake resistance.The research indicates that the pyramid's long existence is not a coincidence but the product of centuries of architectural evolution. Seismologists have been studying the landmark for years to see how it handles heavy vibrations. By following the way energy rippled through the structure, the research team found that the ancient Egyptians knew how to distribute mechanical stress very well. Their construction methods effectively made the massive tomb an accidental shock absorber.A profound lesson in good vibrationsTo unravel the mystery, scientists equipped 37 diverse sites around the ancient complex with sophisticated sensors, including the most profound internal chambers and the surrounding ground. I didn’t expect the results. They found 76 per cent of the vibrations occurring inside the monument were at a certain frequency, between 2.0 and 2.6 hertz. Meanwhile, the native ground below trembled at a much lower rate of 0.6 hertz.This large frequency change is actually the shield of the pyramid. That difference prevents the heavy vibrations of the ground from getting bigger as they go up into the stone blocks when an earthquake hits. The monument was built directly on a solid foundation of limestone bedrock, which also protected it from the violent swaying that usually brings down modern skyscrapers.There’s a safety valve in the interior design, too. Scientists taking measurements in the upper sections noted that the famous Relieving Chambers – the big granite spaces stacked directly above the King’s Chamber - had far less vibration amplification than they expected. This suggests that the upper chambers are a structural buffer that intentionally absorbs the kinetic energy before it can break the ceiling of the main tomb below it. Trial and Error and Unmatched Engineering InstinctSuch a degree of structural stability was not achieved overnight. It took the builders a long process of trial and error, over generations, to get here. Before the famous smooth slopes of Giza, Egyptian architects experimented with simpler, flat-topped mastaba tombs. And then there were the stacked structures, such as the Step Pyramid of Djoser, and the strangely shaped Bent Pyramid, which has a sudden change of angle halfway up, because the original slope was too steep to support its own weight.When an experimental building failed, either collapsing or cracking, the ancient planners studied the failure and revised their blueprints. For hundreds of years, the goal has been to perfect the angle and weight distribution. The Great Pyramid is the crowning apex of this long line of historical trials.It’s easy to imagine the pharaohs had sophisticated seismic formulas, but experts warn against it. The builders probably did not possess the formal mathematical theory of earthquakes that engineers have today. But their success rested on clever intuition and a fanaticism about long-term durability. In trying to create a monument that would endure eternally, they accidentally created one of the most earthquake-proof structures on Earth.