2,000-year-old Chinese earthquake detector works incredibly well using eight dragons

Despite all of the technology we have in the world today, we still haven’t devised a way to predict when or where an earthquake will occur. But we have made tremendous strides when it comes to detecting and measuring seismic shocks when they take place.

But did you know that 2,000 years ago in China a machine was built that could indeed detect earthquakes?


The Chinese seismoscope invented some 2,000 years ago (Via YouTube)

In ancient China — approximately 132 AD — Zhang (‘Chang’) Heng developed the very first method of accurately detecting earthquakes from great distances, and the machine didn’t rely on movement or shaking in the area where the seismoscope was located.


The Amazing Mr. Zhang


According to Ancient Origins, inventor Zhang Heng was an incredibly accomplished man:


“Zhang Heng was an astronomer, mathematician, engineer, geographer and inventor, who lived during the Han Dynasty (25 – 220 AD).  He was renowned for inventing the world’s first water-powered armillary sphere for astronomical observation, improved the water clock, and documented about 2,500 stars in a detaileds star catalog. He is also widely believed to have invented the first odometer. “


Chinese inventor Zhang Heng (Via YouTube)
The Earthquake Detector


Despite his renown as an inventor, it was Zhang’s earthquake detector that brought him the most notice, especially since it could determine the direction of a seismic event from hundreds of miles away.

The device itself is a giant bronze vessel about six feet in total diameter. But it’s the way the vessel is designed and built that makes it such a marvel even to this day:


“Eight dragons snaked face-down along the outside of the barrel, marking the primary compass directions. In each dragon’s mouth was a small bronze ball. Beneath the dragons sat eight bronze toads, with their broad mouths gaping to receive the balls.  His device also included a vertical pin passing through a slot in the crank, a catch device, a pivot on a projection, a sling suspending the pendulum, an attachment for the sling, and a horizontal bar supporting the pendulum – this invention was no mean feat! “

Today we have seismographs to record earthquake waves. But they’re not nearly as beautiful as the Zhang’s machine (Via YouTube)

To this day, we aren’t certain exactly what mechanism caused the ball to drop when an earthquake was sensed. Some have theorized there was a thin stick located down the center of the barrel. Shock waves from a seismic event would then cause the stick to topple in the direction of the earthquake. That in turn would trigger one of the elaborate dragons to open its mouth and release a bronze ball. The sound of the ball when it struck one of the toads on the machine would then serve as a signal that a quake had been detected.


The Palace is Alerted


In the year 138 AD, a noise from one of Zhang’s earthquake detectors located in the royal palace let it be known that an earthquake had occurred. But many remained skeptical, doubting that the device could actually do what it promised.

It was theorized that a seismic event had taken place, but no one could immediately confirm that. A few days later, confirmation arrived:


“A messenger from the western Long region (today, southwest Gansu province), which was west of Luoyang, reported that there had been an earthquake there. As it happened exactly the same time that the seismometer was triggered, people were greatly impressed by Zhang Heng’s instrument.”

The 1935 Shinchiku-Taichū earthquake in China caused tremendous damage (Via Wikimedia Commons)

In 2006, scientists in China were able to replicate Zhang’s seismoscope and then use it to detect simulated earthquakes using shock waves from real quakes that had taken place in China and Vietnam. The results astounded even the most jaded:

“The seismoscope detected all of them. As a matter of fact, the data gathered from the tests corresponded accurately with that gathered by modern-day seismometers!”

While we have much more advanced technology and devices in today’s world, Zhang Heng’s achievement remains remarkable, a tribute to his genius and skills as an inventor.


Here’s more on the 2,000-year-old earthquake machine:


Featured Image Via YouTube Screenshot

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