The first Chinese seismograph was invented 2,000 years ago
The first Chinese seismograph was invented 2,000 years ago

Video: The first Chinese seismograph was invented 2,000 years ago

Video: The first Chinese seismograph was invented 2,000 years ago

In 132 AD in China, the inventor Zhang Heng introduced the first seismoscope believed to be capable of predicting earthquakes with the precision of modern instruments.

Historical records contain an accurate description of its appearance and how it functioned, but the exact internal structure still remains a mystery. Scientists have repeatedly attempted to create a model of such a seismoscope, putting forward various theories about the principle of its operation.

The most common of them says that a pendulum inside a copper bulb is set in motion during tremors, even if the epicenter of the earthquake is hundreds of kilometers away. In turn, the pendulum struck on a system of levers, with the help of which the mouth of one of the eight dragons located outside was opened.

In the mouth of each animal was a bronze ball, which fell into an iron toad, making a loud ringing at the same time. Historical essays say that the sound produced was so loud that it could wake up all the inhabitants of the imperial court.

The dragon, whose mouth was opened, indicated in which direction the earthquake occurred. Each of the eight animals belonged to one of the directions: East, West, North, South, northeast, northwest, southeast and southwest, respectively.

The invention was initially greeted with skepticism, despite the fact that Zhang was already a famous scientist at that time, who was appointed by the imperial court to the post of chief astronomer. But around 138 AD, the bronze ball sounded the first alarm, indicating that the earthquake had occurred west of the capital Luoyang.

The signal was ignored as no one in the city felt the signs of an earthquake. A few days later, a messenger arrived from Luoyang with the news of severe destruction: the city, located at a distance of 300 km, was in ruins as a result of a natural disaster.

A scientist from the Institute of Geophysics in China determined that the first earthquake detected by such a seismoscope occurred on December 13, 134, and had a magnitude of 7.

Thus, the device was created to detect earthquakes in remote regions, but it functioned only during the life of its inventor. Apparently, the device of the first seismoscope was so complex that only the scientist himself could keep it in working order.

Modern attempts to recreate a copy have met with mixed success, and all of them were based on the use of inertia, a principle that is used in modern seismographs.

In 1939, a Japanese scientist created a model of such a seismoscope, but not in all cases the ball fell exactly in the direction of the epicenter of the earthquake.

Scientists from the Chinese Academy of Sciences, the National Museum and the Chinese Seismological Bureau managed to create a more accurate reconstruction of the invention in 2005.

According to the Chinese media, the device reacted accurately to the reproduced waves of the five earthquakes that occurred in Tangshan, Yunnan, the Qinghai-Tibet Plateau and Vietnam. In comparison with modern instruments, the seismoscope showed amazing accuracy, and its shape was the same as described in historical texts.

However, not everyone is inclined to believe in the efficiency of the first seismoscope. Robert Reiterman, executive director of the Universities Consortium for Earthquake Engineering Research, expressed skepticism about the accuracy of the apparatus described in historical stories.

“If the epicenter of the earthquake was at a close distance, the whole structure was shaken so much that balls would fall out of all dragons at the same time. At a distant distance, the movements of the earth do not leave a clear trace in order to identify from which side the vibrations emanate. Since until the moment when the vibrations of the earth's surface reach the seismoscope, they occur in different directions, most likely chaotically, "he writes in his book" Engineers and Earthquakes: An International History."

If the seismoscope really worked as accurately as it was described in the historical records, which is also hinted at by the functioning of modern copies, then Zhang's genius still remains unattainable.