Zhang Heng and the world's first seismograph. What is a seismograph and what is it for? In which country was the first seismograph invented?

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

An accurate description of it has been preserved in historical records. 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 flask begins to move during tremors, even if the epicenter of the earthquake is hundreds of kilometers away. In turn, the pendulum struck a system of levers, with the help of which the mouth of one of the eight dragons located outside opened.

Reconstruction of an ancient seismoscope from the Eastern Han Dynasty (25-220 AD) and its inventor Zhang

In the mouth of each animal there was a bronze ball, which fell into the iron toad, making a loud ringing sound. Historical accounts say that the sound produced was so loud that it could wake up everyone in the imperial court.

The dragon, whose mouth 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 met with skepticism, despite the fact that Zhang was already a famous scientist at that time, whom the imperial court appointed to the post of chief astronomer. But around 138 AD, the bronze ball sounded the first alarm, indicating that an earthquake had occurred west of the capital Luoyang.

The signal was ignored because no one in the city felt any signs of an earthquake. A few days later, a messenger arrived from Luoyang with news of severe destruction: a city located 300 km away 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 for the purpose of detecting earthquakes in remote regions, but it functioned only during the lifetime of its inventor. Apparently, the design of the first seismoscope was so complex that only the scientist himself could maintain it in working order.

Modern attempts to recreate the replica have met with mixed success, and all were created using inertia, a principle that is also 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 earthquake epicenter.

A more accurate reconstruction of the invention was created jointly by scientists from the Chinese Academy of Sciences, the National Museum and the China Seismological Bureau in 2005.

According to Chinese media, the device responded accurately to the reproduced waves of five earthquakes that occurred in Tangshan, Yunnan, the Qinghai-Tibet Plateau and Vietnam. Compared to 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 effectiveness of the first seismoscope. Robert Reiterman, executive director of the University Consortium for Earthquake Engineering Research, expressed skepticism about the accuracy of the apparatus described in historical accounts.

“If the epicenter of the earthquake was at a close distance, the entire structure would shake so much that the balls would simultaneously fall out of all the dragons. At a long distance, the movements of the earth do not leave a clear trace to identify which side the vibrations are coming from. Since until the moment when 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 historical records, as is also hinted at by the functioning of modern copies, then Zhang's genius still remains elusive.

Zhang Heng(78 - 139) - Chinese philosopher, encyclopedist thinker, writer, poet, statesman and a scientist who owns world discoveries and inventions in mathematics, astronomy, mechanics, seismology and geography.

Seismograph

Seismograph- a special measuring device that is used to detect and record all types of seismic waves. In most cases, the seismograph has a weight with a spring attachment, which during an earthquake remains motionless, while the rest of the device (body, support) begins to move and shifts relative to the load. Some seismographs are sensitive to horizontal movements, others to vertical ones. The waves are recorded by a vibrating pen on a moving paper tape. There are also electronic seismographs (without paper tape).

Until recently, mechanical or electromechanical devices were mainly used as seismograph sensing elements. It is quite natural that the cost of such instruments containing elements of precision mechanics is so high that they are practically inaccessible to the average researcher, and the complexity mechanical system and, accordingly, the requirements for the quality of its execution actually mean the impossibility of manufacturing such devices on an industrial scale.

The rapid development of microelectronics and quantum optics has currently led to the emergence of serious competitors to traditional mechanical seismographs in the mid- and high-frequency regions of the spectrum. However, such devices based on micromachine technology, fiber optics or laser physics have very unsatisfactory characteristics in the region of infra-low frequencies (up to several tens of Hz), which is a problem for seismology (in particular, the organization of teleseismic networks).

There is also a fundamentally different approach to constructing the mechanical system of a seismograph - replacing the solid inertial mass with a liquid electrolyte. In such devices, an external seismic signal causes a flow of working fluid, which, in turn, is converted into electric current using a system of electrodes. Sensitive elements of this type are called molecular electronic. The advantages of seismographs with liquid inertial mass are low cost, long service life (about 15 years), and the absence of precision mechanics elements, which greatly simplifies their manufacture and operation.

Computerized seismic measuring systems

With the advent of computers and analog-to-digital converters, the functionality of seismic equipment has increased dramatically. It is now possible to simultaneously record and analyze in real time signals from several seismic sensors and take into account signal spectra. This provided a fundamental leap in the information content of seismic measurements.

Examples of seismographs

Molecular electron seismograph. .
Autonomous bottom seismograph. . Archived from the original on December 3, 2012.

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Synonyms:

See what a “Seismograph” is in other dictionaries:

Seismograph... Spelling dictionary-reference book

- (Greek, from seismos vibration, shaking, and grapho I write). An apparatus for observing earthquakes. Dictionary foreign words, included in the Russian language. Chudinov A.N., 1910. SEISMOGRAPH Greek, from seismos, shock, and grapho, I write. Apparatus for... ... Dictionary of foreign words of the Russian language

Syn. term seismic receiver. Geological Dictionary: in 2 volumes. M.: Nedra. Edited by K. N. Paffengoltz et al. 1978 ... Geological encyclopedia

Geophone, seismic receiver Dictionary of Russian synonyms. seismograph noun, number of synonyms: 2 geophone (1) ... Dictionary of synonyms

- (from seismo... and...graph) a device for recording vibrations of the earth's surface during earthquakes or explosions. The main parts of a seismograph are the pendulum and the recording device... Big Encyclopedic Dictionary

- (seismometer), a device for measuring and recording SEISMIC WAVES caused by movement (EARTHQUAKE or explosion) in the earth's crust. The vibrations are recorded using a recording element on a rotating drum. Some seismographs are capable of detecting... Scientific and technical encyclopedic dictionary

SEISMOGRAPH, seismograph, husband. (from the Greek seismos shaking and grapho I write) (geol.). A device for automatically recording vibrations of the earth's surface. Dictionary Ushakova. D.N. Ushakov. 1935 1940 ... Ushakov's Explanatory Dictionary

SEISMOGRAPH, huh, husband. A device for recording vibrations of the earth's surface during earthquakes or explosions. Ozhegov's explanatory dictionary. S.I. Ozhegov, N.Yu. Shvedova. 1949 1992 … Ozhegov's Explanatory Dictionary

Seismograph- - a device designed to record vibrations of the earth's surface caused by seismic waves. It consists of a pendulum, for example, a steel weight, which is suspended on a spring or thin wire from a stand firmly fixed in the ground.... ... Oil and Gas Microencyclopedia

seismograph- Conversion device mechanical vibrations soil in electric and subsequent recording on photosensitive paper. [Dictionary of geological terms and concepts. Tomsk State University] Topics geology, geophysics Generalizing... ... Technical Translator's Guide

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| Seismograph

Seismograph (Greek origin and is formed from two words: “ seismos" - shaking, shaking, and " grapho" - write, record) - special meter, which is used in seismology to detect and record all types of seismic waves.

Ancient times

China is famous for its inventions, but they, alas, become outdated and change. Paper has evolved to digital media, gunpowder has long become “liquid”, and even compasses have come in more than a dozen varieties. Or, for example, a seismograph. Modern apparatus for recording earth vibrations, it looks solid - like a lie detector or a spy device. It is not at all like the very first seismograph - a little ridiculous in appearance, but quite accurate. It was invented during the Han Dynasty (25-220 AD) by the scientist Zhang Heng.

The creator of the first seismograph was born in Nanyang (Henan Province). Even as a child, Han showed a love for science. Over the years he entered Chinese history and did a lot of useful things for astronomy and mathematics. IN historical notes At that time, it appears that this inventor was calm and balanced and tried to keep a low profile. In addition to his passion for science, Zhang Heng knew how to write poetry.

Inventor of the seismograph

Earthquake – imbalance between Yin and Yang In ancient times, it was believed that earthquakes were a very unkind sign and the wrath of heaven. In ancient Chinese philosophy, a special teaching was even invented that examined the balance between the two forces of Yin and Yang. Naturally, this science could not do without explaining such a phenomenon as an earthquake. According to the Chinese of that time, the earth was shaking for a reason, but because of a global imbalance.

Why do earthquakes sometimes occur, the force of which can lead to disaster? Everything was attributed to the wrong decisions of the Chinese rulers. Have taxes increased? Heaven will punish China with an earthquake! War started? Expect trouble! A large percentage of the earthquakes that occurred then were meticulously described. Historians considered it important to write about everything that happened on such an unfavorable day.

Thanks to Zhang Heng's research, it was found that earthquakes are a natural phenomenon that can be known about in advance. For this purpose he created a seismograph.

The operating principle of the first Chinese seismograph

The scheme according to which the device worked was as follows:

When an earthquake began, the first tremors of the earth caused the detector to shake.

At the same time, the ball, which was placed inside the dragon, began to move.

Then he fell from the mouth of the mythical reptile directly into the mouth of the toad.

The working principle of the Chinese seismograph
As the ball fell, a characteristic clanging sound was heard. Surprisingly, the first seismograph even indicated the direction in which the epicenter of the earthquake was located (for this, additional dragons were attached to the device). For example, if the ball fell out of the dragon from the eastern part of the device, then trouble should be expected in the west.

The first seismograph is not only a scientific, but also an artistic artifact. Why does its design include dragons and toads? They are a philosophical symbol of time. Accordingly, dragons are Yin, and toads are Yang. The interaction between them symbolizes the balance between “up” and “down”. Even taking into account everyone scientific discoveries, Zhang Heng did not forget to weave traditional beliefs into his invention.

Fate is a villain

The fate of many ancient scientists was not the most rosy (some were even burned at the stake for their beliefs). Indeed, it is one thing to invent something that will glorify you for centuries, and another thing to make sure that your contemporaries appreciate you. Even Zhang Heng could not avoid skepticism when demonstrating the seismograph to Emperor Shun Yang Jia. The courtiers reacted to the scientist's invention with great distrust.

Skepticism was a little dispelled in 138 AD, when Zhang Heng's seismograph recorded an earthquake in the Longxi region. But even after proving that the device worked successfully in the field, most were afraid of Zhang Heng. Yes, the ancient Chinese were not without superstitions.

Chinese seismograph

Exact copy of the device

The original seismograph has long since sunk into oblivion. However, Chinese and foreign scientists who researched Zhang Heng's works were able to reconstruct his invention. Recent tests confirm that an ancient Chinese seismograph can detect an earthquake with an accuracy that is almost as good as modern equipment.

Chinese seismograph in a museum
Today, the recreated ancient seismograph is kept in the exhibition hall of the Chinese History Museum in Beijing.

19th century

In Europe, earthquakes began to be seriously studied much later.

In 1862, the book “The Great Neapolitan Earthquake of 1857: Basic Principles of Seismological Observations” was published by the Irish engineer Robert Malet. Malet made an expedition to Italy and drew up a map of the affected territory, dividing it into four zones. The zones introduced by Malet represent the first, rather primitive, scale of shaking intensity. But seismology as a science began to develop only with the widespread appearance and introduction into practice of instruments for recording ground vibrations, i.e., with the advent of scientific seismometry.

In 1855, Italian Luigi Palmieri invented a seismograph capable of recording distant earthquakes. It operated on the following principle: during an earthquake, mercury was spilled from a spherical volume into a special container, depending on the direction of vibration. The container contact indicator stopped the watch, indicating exact time, and started recording earth vibrations on the drum.

In 1875, another Italian scientist, Filippo Sechi, designed a seismograph that turned on a clock at the moment of the first shock and recorded the first vibration. The first seismic record that has come down to us was made using this device in 1887. After this, rapid progress began in the field of creating instruments for recording ground vibrations. In 1892, a group of English scientists working in Japan created the first fairly easy-to-use device, the John Milne seismograph. Already in 1900, a worldwide network of 40 seismic stations equipped with Milne instruments was operating.

XX century

First seismograph modern design invented by the Russian scientist, Prince B. Golitsyn, who used the transformation of mechanical vibration energy into electric current.

B. Golitsyn
The design is quite simple: the weight is suspended on a vertically or horizontally located spring, and a recorder pen is attached to the other end of the weight.

Rotating paper tape used to record load vibrations. The stronger the push, the further the pen deflects and the longer the spring oscillates. A vertical weight allows you to record horizontally directed shocks, and vice versa, a horizontal recorder records shocks in the vertical plane. As a rule, horizontal recording is carried out in two directions: north-south and west-east.

Conclusion

As a rule, major earthquakes do not arise unexpectedly. They are preceded by a series of small, almost imperceptible shocks of a special nature. By learning to predict earthquakes, people will be able to avoid death due to these disasters and minimize the material damage they cause.

It’s hard to imagine, but about a million earthquakes occur on our planet every year! Of course, these are mostly weak tremors. Earthquakes of destructive force occur much less frequently, averaging once every two weeks. Fortunately, most of them occur at the bottom of the oceans and do not cause any trouble to humanity, unless a tsunami occurs as a result of seismic displacements.

Everyone knows about the catastrophic consequences of earthquakes: tectonic activity awakens volcanoes, giant tidal waves wash away entire cities into the ocean, faults and landslides destroy buildings, cause fires and floods and claim hundreds and thousands of human lives.

Therefore, people at all times have sought to study earthquakes and prevent their consequences. Thus, Aristotle in the 4th century. before i. e. believed that atmospheric vortices penetrate into the ground, which has many voids and crevices. The vortices are intensified by fire and seek a way out, causing earthquakes and volcanic eruptions. Aristotle also observed the movements of the soil during earthquakes and tried to classify them, identifying six types of movements: up and down, from side to side, etc.

The first known attempt to make an instrument that predicted earthquakes belongs to Chinese philosopher and astronomer Zhang Heng. In China, these natural disasters have happened and are happening extremely often; moreover, three of the four largest earthquakes in human history occurred in China. And in 132, Zhang Heng invented a device, which he gave the name Hoofeng “earthquake weather vane” and which could record vibrations of the earth’s surface and the direction of their propagation. Hoofeng became the world's first seismograph (from the Greek seismos "oscillation" and grapho "write") a device for detecting and recording seismic waves.

Consequences of the 1906 San Francisco earthquake.

Strictly speaking, the device was more like a seismoscope (from the Greek skopeo “I look”), because its readings were recorded not automatically, but by the hand of an observer.

Hoofeng was made of copper in the shape of a wine vessel with a diameter of 180 cm and thin walls. Outside the vessel were eight dragons. The dragons' heads pointed to eight directions: east, south, west, north, northeast, southeast, northwest and southwest. Each dragon held a copper ball in its mouth, and under its head sat a toad with its mouth open. It is assumed that a pendulum with rods was installed vertically inside the vessel, which were attached to the heads of the dragons. When, as a result of an underground shock, the pendulum began to move, a rod connected to the head facing the direction of the shock opened the dragon’s mouth, and the ball rolled out of it into the mouth of the corresponding toad. If two balls rolled out, the strength of the earthquake could be assumed. If the device was at the epicenter, then all the balls rolled out. Observers of the instrument could immediately record the time and direction of the earthquake. The device was very sensitive: it detected even weak tremors, the epicenter of which was located 600 km away. In 138, this seismograph accurately indicated an earthquake that occurred in the Longxi region.

In Europe, earthquakes began to be seriously studied much later. In 1862, the book “The Great Neapolitan Earthquake of 1857: Basic Principles of Seismological Observations” was published by the Irish engineer Robert Malet. Malet made an expedition to Italy and drew up a map of the affected territory, dividing it into four zones. The zones introduced by Malet represent the first, rather primitive, scale of shaking intensity.

But seismology as a science began to develop only with the widespread appearance and introduction into practice of instruments for recording ground vibrations, i.e., with the advent of scientific seismometry.

In 1855, Italian Luigi Palmieri invented a seismograph capable of recording distant earthquakes. It operated on the following principle: during an earthquake, mercury was spilled from a spherical volume into a special container, depending on the direction of vibration. The contact indicator with the container stopped the watch, indicating the exact time, and triggered a recording of ground vibrations on the drum.

A seismograph consists of a pendulum of one design or another and a system for recording its vibrations. According to the method of recording pendulum oscillations, seismographs can be divided into devices with direct registration, mechanical vibration transducers and seismographs with feedback.

Direct recording seismographs use a mechanical or optical recording method. Initially when mechanically recording, a pen was placed at the end of the pendulum, scratching a line on smoked paper, which was then covered with a fixing compound. But the pendulum of a seismograph with mechanical recording is strongly influenced by the friction of the pen on the paper. To reduce this influence, a very large pendulum mass is needed.

With the optical recording method, a mirror was fixed on the rotation axis, which was illuminated through the lens, and the reflected beam fell on photographic paper wound on a rotating drum.

The direct recording method is still used in seismically active zones where ground movements are quite large. But to register weak earthquakes and at large distances from their sources, it is necessary to intensify the oscillations of the pendulum. This is carried out by various converters of mechanical movements into electrical current.

Diagram of the propagation of seismic waves from the earthquake source, or hypocenter (bottom) and epicenter (top).

The transformation of mechanical vibrations was first proposed by the Russian scientist Boris Borisovich Golitsyn in 1902. It was a galvanometric recording based on the electrodynamic method. An induction coil rigidly attached to the pendulum was placed in the field permanent magnet. When the pendulum oscillated, the magnetic flux changed, an electromotive force arose in the coil, and the current was recorded by a mirror galvanometer. A beam of light was directed onto the galvanometer mirror, and the reflected beam, as with the optical method, fell on photographic paper. Such seismographs won worldwide recognition for many decades to come.

IN lately so-called parametric converters have become widespread. In these converters mechanical movement(movement of the pendulum mass) causes a change in some parameter electrical circuit(For example, electrical resistance, capacitance, inductance, luminous flux, etc.).

B. Golitsyn.

Seismological station adit. The equipment installed there records even the slightest vibrations in the soil.

Mobile installation for geophysical and seismological research.

Changing this parameter leads to a change in the current in the circuit, and in this case it is the displacement of the pendulum (and not its speed) that determines the magnitude of the electrical signal. Of the various parametric converters in seismometry, the two mainly used are photoelectric and capacitive. The most popular is the capacitive Benioff converter. Among the selection criteria, the main ones were simplicity of the device, linearity, low noise level, and energy efficiency.

Seismographs can be sensitive to vertical or horizontal vibrations of the earth. To observe the movement of the soil in all directions, three seismographs are usually used: one with a vertical pendulum and two with horizontal pendulums oriented to the east and north. Vertical and horizontal pendulums differ in their design, so it turns out to be quite difficult to achieve complete identity of their frequency characteristics.

Seismographs are used primarily to study the earthquake phenomenon itself. With their help, it is possible to determine instrumentally the strength of an earthquake, the place of its occurrence, the frequency of occurrence in a given place and the predominant places where earthquakes occur.

Equipment of a seismological station in New Zealand.

Basic information about internal structure The Earth was also obtained from seismic data by interpreting the fields of seismic waves caused by earthquakes and powerful explosions and observed on the Earth's surface.

Using seismic wave recordings, structural studies are also carried out earth's crust. For example, studies from the 1950s show that the thickness of crustal layers, as well as the speeds of waves in them, vary from place to place. In Central Asia, the thickness of the crust reaches 50 km, and in Japan -15 km. A map of the thickness of the earth's crust has been created.

We can expect that new technologies in inertial and gravitational measurement methods will soon appear. It is possible that the new generation of seismographs will be able to detect gravitational waves in the Universe.

Seismograph recording

Scientists around the world are developing projects to create satellite earthquake warning systems. One such project is the Interferometric-Synthetic Aperture Radar (InSAR). This radar, or rather radars, tracks the displacement tectonic plates in a certain area, and thanks to the data they obtain, even subtle displacements can be recorded. Scientists believe that thanks to this sensitivity, it is possible to more accurately identify areas of high stress and seismic-hazardous zones.

Seismograph(from ancient Greek σεισμός - earthquake and ancient Greek γράφω - to write down) or seismometer- a measuring device that is used in seismology to detect and record all types of seismic waves. A device for determining the strength and direction of an earthquake.

The first known attempt to make a device that predicts earthquakes belongs to the Chinese philosopher and astronomer Zhang Heng.

ZhangHeng invented a device, which he gave the name Houfeng " "and which could record vibrations of the earth's surface and the direction of their propagation.

Houfeng became the world's first seismograph. The device consisted of a large bronze vessel with a diameter of 2 m, on the walls of which were located eight dragon heads. The dragons' jaws opened, and each one had a ball in its mouth.

Inside the vessel there was a pendulum with rods attached to the heads. As a result of the underground shock, the pendulum began to move, acted on the heads, and the ball fell out of the dragon’s mouth into the open mouth of one of the eight toads sitting at the base of the vessel. The device detected tremors at a distance of 600 km from it.

1.2. Modern seismographs

First seismograph modern design was invented by the Russian scientist, Prince B. Golitsyn, which used the conversion of mechanical vibration energy into electrical current.

The design is quite simple: the weight is suspended on a vertically or horizontally located spring, and a recorder pen is attached to the other end of the weight.

A rotating paper tape is used to record the vibrations of the load. The stronger the push, the further the pen deflects and the longer the spring oscillates.

A vertical weight allows you to record horizontally directed shocks, and vice versa, a horizontal recorder records shocks in the vertical plane.

As a rule, horizontal recording is carried out in two directions: north-south and west-east.

In seismology, depending on the problems being solved, different types of seismographs are used: mechanical, optical or electrical with various types amplifications and signal processing methods. A mechanical seismograph includes a sensing element (usually a pendulum and damper) and a recorder.

The base of the seismograph is rigidly connected to the object under study, and when it oscillates, the load moves relative to the base. The signal is recorded in analog form on recorders with mechanical recording.

1.3. Creation of a seismograph

Materials: Carton; awl; ribbon; plasticine; pencil; felt-tip pen; twine or strong thread; a piece of thin cardboard.

The frame for the seismograph will be carton. It needs to be made of a fairly rigid material. Its open side will be the front part of the device.

It is necessary to make a hole in the top cover of the future seismograph with an awl. If the rigidity for " frames"is not enough, you need to cover the corners and edges of the box with tape, strengthening it, as shown in the photo.

Roll a plasticine ball and make a hole in it with a pencil. Push the felt-tip pen into the hole so that its tip protrudes slightly from the opposite side of the plasticine ball.

This is a seismograph pointer designed to draw lines of earth vibrations.

Pass the end of the thread through the hole in the top of the box. Place the box on the bottom side and tighten the thread so that the felt-tip pen hangs freely.

Tie the top end of the thread to a pencil and rotate the pencil around its axis until you take out the slack in the thread. Once the marker is hanging at the desired height (that is, just touching the bottom of the box), secure the pencil in place with tape.

Slide a piece of cardboard under the tip of the felt-tip pen into the bottom of the box. Adjust everything so that the tip of the felt-tip pen easily touches the cardboard and can leave lines.

The seismograph is ready for use. It uses the same operating principle as the real equipment. A weighted suspension, or pendulum, will be more inertial to shaking than a frame.

There is no need to wait for an earthquake to test the device in action. You just need to shake the frame. The pendant will remain in place, but will begin to draw lines on the cardboard, just like a real one.