According to the Records of Zhang Hengchuan in the Later Han Dynasty, Hou Feng's seismograph is made of pure copper, with a round diameter of eight feet, shaped like a wine bottle, with a raised round cover, and its appearance is engraved with seal characters and figures of mountains, turtles, birds and animals. There is a copper "capital column" in the center of the instrument, and there are eight channels beside the column, called "eight channels", as well as exquisite machines and switches. There are eight faucets around the outside of the bottle, which are arranged in eight directions: east, south, west, north, southeast, northeast, southwest and northwest. The faucet is connected with the engine in the internal passage, and there is a copper ball in the mouth of each faucet. Facing the faucet, eight toads squatted on the ground, all with their heads held high and their mouths open, ready to accept copper balls. When an earthquake occurs in a certain place, the bottle moves with it, touching the mechanism, making the faucet in the direction of the earthquake open its mouth, spitting out the copper ball and falling into the mouth of the copper toad, making a loud noise. So people can know the direction of the earthquake.
Edit this historical demonstration.
In November of the third year of Yang Jia, Emperor Shundi of Han Dynasty (AD 134 13 February), a dragon machine of the seismograph suddenly started, spit out a copper ball and fell into toad's mouth. At that time, people in the capital (Luoyang) did not feel any signs of the earthquake, so some people began to talk about it, blaming the seismograph for its ineffectiveness. A few days later, a flying horse came to Longxi (now Tianshui, Gansu) and reported that an earthquake did happen there a few days ago, so people began to believe in Zhang Heng's superb technology. Longxi is more than 1000 miles away from Luoyang, and the seismograph marks correctly, which shows that its seismic sensitivity is relatively high.
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Zhang heng
During the reign of Zhang Han, the politics of the Eastern Han Dynasty was relatively stable. When he died, Emperor Wu of the Han Dynasty and his successors were only ten years old. Dou Taihou came to power, letting his younger brother Dou Xian hold the power of state affairs. The Eastern Han Dynasty began to decline. During this period, a famous scientist Zhang Heng appeared. Zhang Heng is from Nanyang. He left his hometown at the age of seventeen and went to Chang 'an and Luoyang successively, studying hard in imperial academy. Zhang heng
At that time, Luoyang and Chang 'an were both very prosperous cities, and the princes and nobles in the city lived a luxurious life. Zhang Heng doesn't like these. He wrote two literary works, Xijing Fu and Tokyo Fu (Xijing is Chang 'an and Tokyo is Luoyang), satirizing this phenomenon. It is said that it took him ten years to write these two works after careful consideration and repeated revisions, which shows that his spirit of studying knowledge is very serious. But Zhang Heng's major is not literature, and he is particularly interested in mathematics and astronomical research. When the court heard that Zhang Heng was a learned man, it called him to be an official in Beijing. First as a doctor in the palace, then as an official, he was put in charge of observing astronomy. This job coincides with his interest in research. After his observation and research, he came to the conclusion that the earth is round and the moon reflects the light of the sun. He also thinks that the sky is like an eggshell, wrapped outside the ground; The ground is like egg yolk, in the middle of the sky. Although this theory is not completely accurate, it was impossible to express this scientific opinion more than 800 years ago without being praised by later astronomers. Not only that, Zhang Heng also made an instrument for measuring astronomy with copper, called "Hunyi". It is engraved with astronomical phenomena such as the sun, moon and stars. He tried to use water power to turn the instrument. It is said that what stars rise and fall in the west can be clearly seen on the armillary sphere.
seismometer
During that period, earthquakes often occurred. Sometimes once a year, sometimes twice a year. A big earthquake happened, which affected dozens of counties. Walls and houses collapsed, killing and injuring many people and animals. At that time, the feudal emperors and ordinary people regarded the earthquake as an ominous sign, and some even took the opportunity to publicize superstition and deceive the people. However, Zhang Heng does not believe in God or evil spirits. After careful investigation and experiments on the recorded earthquake phenomena, he invented an instrument for predicting earthquakes, called "seismograph". The seismograph is made of bronze, a bit like a jar. There are eight dragons carved around, and the bibcock extends in eight directions. Every dragon has a small copper ball in its mouth: under the tap, a bronze toad crouches, aiming at the dragon's mouth and opening it. When there is an earthquake in any direction, the dragon mouth in that direction will automatically open and spit out copper balls. The copper ball fell into toad's mouth and made a loud noise, giving people an earthquake warning. seismometer
One day in February of AD 138, Zhang Heng's seismograph suddenly opened its mouth to the west and spit out a copper ball. According to Zhang Heng's design, this is to report the earthquake in the west. However, there was no sign of an earthquake in Luoyang that day, and there was no news of an earthquake nearby. Therefore, people have been talking about Zhang Heng's seismograph as a lie, and some even say that he intends to spread rumors. A few days later, someone rode a fast horse and reported to the court that there was a big earthquake in Jincheng and Longxi, more than 1000 miles away from Luoyang, and even the mountains collapsed. Everyone is convinced. But at that time, the imperial court was in power of eunuchs or consorts, and talents like Zhang Heng were not only not reused, but were hit and excluded. When Zhang Heng was a waiter, because he was close to the emperor, the eunuch was afraid that Zhang Heng would expose their shortcomings in front of the emperor, so he spoke ill of Zhang Heng in front of the emperor. He was transferred from Beijing and became a county magistrate in Hejian. Zhang Heng died of illness at the age of 61. He left brilliant achievements in the history of science in China.
Edit this paragraph of the earliest seismograph.
This musical instrument is made of copper and shaped like a wine bottle. There are eight faucets around. Faucets face east, south, west, north, southeast, southwest, northeast and northwest. Longkou is movable, and there is a small copper ball in each mouth. Under each tap, there is a copper toad with its mouth wide open. There is a copper pendulum in the center of the instrument, and there are eight channels beside the column, which are called "Eight Classics" and ingenious mechanisms. When an earthquake occurs in a certain place, the suspension pendulum moves the ball through the "eight roads" and touches the mechanism, so that the faucet in the earthquake direction opens its mouth and spits out the copper ball, which falls into the mouth of the copper toad and makes a loud noise. So people can know the direction of the earthquake. seismometer
Through the earthquake inspection in southwest Gansu in A.D. 134, the accuracy of its earthquake measurement was completely confirmed. It is 1700 years earlier than similar seismographs created in Europe. Unfortunately, the seismographs of the Eastern Han Dynasty have long been lost, and the seismographs we see now are all restored by later generations according to historical records. After the seismograph was made, it was placed in Luoyang. One day in A.D. 138, as usual, there was no movement around Kyoto, but the small steel ball was unusually spit out from Longkou and fell into toad's mouth. The exciting noise shocked all around and people talked about it. The earth didn't shake. Why do seismographs report earthquakes? It is likely that the seismograph is broken. Who knows that a few days later, the news of an earthquake in Longxi (now the west of Gansu Province) came, which vividly proved how sensitive and accurate the seismograph is! Because the seismograph only records the general direction of the earthquake, not the seismic wave, it is equivalent to a seismograph, not a real seismograph. The seismograph invented by Zhang Heng initiated the history of using scientific instruments to predict earthquakes. For a long time, Chinese and foreign scientists have been giving high praise to this. It is considered that it is designed and made by using the principle of inertia, and can detect the main impact direction of seismic waves. At the beginning of the 2nd century, when science and technology were still very backward, it was extremely valuable to be able to do this. Compared with similar seismographs abroad, it is 1 10,000 years earlier.
In this section, the development of modern seismographs is edited.
1855, Italian scientist Lu Yiji Parmele invented the first real seismograph. It has a complicated mechanical system. This machine uses a round tube filled with mercury and is equipped with an electromagnetic device. When the vibration makes the mercury shake, the electromagnetic device will trigger the built-in device to record the crustal movement, which roughly shows the time and intensity of the earthquake. The first accurate seismograph was invented by British geographer John Milne in 1880. He is also called "the father of seismograph". With the help of colleagues James Ewing and thomas gray of Imperial University, John Milne invented a variety of devices for detecting seismic waves, one of which is the horizontal pendulum seismic wave detector. This ingenious device has a weighted stick. When it is vibrated, it will move a metal plate with smooth seams (slender seams through which light can pass). The movement of the metal plate makes a beam of reflected light pass through the light slit on the plate, and at the same time, it passes through another static light slit under the plate and falls on a high-sensitivity paper. Then, the light will "record" the movement of the earthquake. Today, most seismographs are still designed according to the principle invented by Milne and his assistant. Scientists will continue to detect the vibration of the earth by studying the correlation between crustal movement and pendulum swing. seismometer
1906, Russian prince Boris gretchen invented the first electromagnetic seismograph. In the design of this machine, he adopted the electromagnetic induction principle put forward by British physicist michael faraday in19th century. Faraday induction principle holds that the change of magnetic line density of a magnet can generate charge. On this basis, Gretchen made an instrument, which can directly measure and record the current by passing the coil through a magnetic field when it feels vibration. Then the current moves a mirror, just like the metal plate that Milne made to guide the light. The advantage of this kind of electronic equipment is that the recorder can be placed in the laboratory, while the seismograph can be placed in a relatively remote place where earthquakes may occur. In the 20th century, the appearance of nuclear energy testing system promoted the development of modern seismographs. Although earthquakes will cause great losses to personal and property safety, it was not until the threat of underground nuclear explosion prompted 1960 to establish a worldwide earthquake monitor network (WWSSN) that seismographs were put into use on a large scale, and more than 60 countries set up 120 seismographs. The Press Ewing seismograph developed after World War II enabled researchers to record long-period seismic waves-waves spread at a relatively slow speed for a long time. The pendulum used in this seismograph is similar to the pendulum used in Milne model, except that elastic metal wires are used instead of weighted rods supported by pivots to reduce friction. After the war, the seismograph was improved as follows: automatic timer was introduced to make the timing more accurate, and lion reader was used to input the data into the computer for analysis. seismometer
The most important development of modern seismograph is the application of geophone combination. This combination, some of which consist of hundreds of seismographs, is connected to a single central recorder. By comparing seismograms produced in different places, researchers can determine the location of the epicenter.
Edit this paragraph classification
At present, there are three kinds of seismometers used in earthquake research, and each seismometer has a period corresponding to the amplitude (speed and intensity) of the earthquake vibration to be measured (period refers to the length of time required for a pendulum to complete a swing, or the time required for a swing back and forth).
Short-period seismograph
It is usually used to study primary and secondary vibrations and measure the fastest moving seismic waves. This is because these seismic waves move very fast, and short-period seismographs can complete a swing in less than one second. It is also possible to enlarge the recorded seismic map, so that researchers can see the trajectory of the instantaneous movement of the crust.
Long-period seismograph
The pendulum used generally takes about 20 seconds to complete a swing, which can be used to measure the slow movement of the earth's crust after the first and second earthquakes. This type of tool is now used in seismic detector networks.
Ultra-long or broadband seismograph
The seismograph with the longest pendulum swing period is called ultra-long or broadband seismograph. Wideband seismographs are widely used, which can usually provide more comprehensive information about global crustal movement.
Edit the current seismograph in this section.
seismometer
The instrument for recording seismic waves is called seismograph, which can record ground vibration objectively and timely. Its basic principle is to use the inertia of a suspended weight, and the ground vibrates while it is stationary when an earthquake occurs. The vibration recorded by seismograph is a curve with different fluctuation amplitude, which is called seismic spectrum. The amplitude of curve fluctuation corresponds to the amplitude of ground vibration caused by seismic wave, indicating the intensity of earthquake. The influence of various seismic waves can be clearly distinguished from the seismic spectrum. The time difference and instantaneous difference of P wave and S wave arriving at the same seismic station are directly proportional to the distance between the epicenter and the seismic station, and the farther away from the epicenter, the greater the time difference. According to this rule, we can get the distance between the epicenter and the seismic station, that is, the epicentral distance. It is worth noting that seismographs can only be used to measure the intensity and direction of earthquakes, but not to predict earthquakes.
In this section, the development of editing measurement technology.
In A.D. 132, a surprising news came from the capital (Luoyang, Henan Province), saying that the Taishi asked Zhang Heng to invent an instrument for observing the time and place of earthquakes. However, some people don't believe that the earthquake happened hundreds of miles away. How can that person detect it? Isn't this "winning a thousand miles"? Zhang Heng was born in 78 AD and died in 139. He was an outstanding scientist in ancient China. He has made outstanding achievements in mathematics, astronomy and earthquakes. The instrument invented by Zhang Heng is called the seismograph, which is the first seismograph in the world. According to the records of the later Han Dynasty, the seismograph is made of pure copper with a round diameter of eight feet. It looks like a wine bottle. The organ is installed in a bottle with Yi Long, which is divided into eight directions: east, west, south, north, northeast, southeast, southwest and northwest. Each dragon has a small copper ball in its mouth, and a copper toad is squatting on the ground beside its mouth. Then, touch the lever of the faucet, so that the longkou at that position opens, and the small copper ball contained in the longkou naturally falls into the toad's mouth on the ground, making a "clanking sound" to let the observer know when and where the earthquake will occur. 134, 12, 13, the longkou in the west of this seismograph opened, and the copper ball fell into the toad's mouth with a clang, indicating that an earthquake occurred in the west of Luoyang. However, because Luoyang did not feel the vibration, many people said that this instrument was not allowed. A few days later, the messenger Feima came to report that an earthquake had occurred in Longxi (southeast Gansu), more than a thousand miles west of Luoyang, and the court was "convinced." The modern seismograph was made in 1880. Its principle is basically similar to that of Zhang Heng's seismograph, but it is more than 1700 years later. The first seismic observatory in China was established at 1930 under the auspices of the famous seismologist Li Shanbang, located in Jiu Feng. After more than half a century's struggle, the number of seismic stations in China has grown from one to several hundred. At present, China has a national basic network and a rapid earthquake reporting network, which can be recorded by seismographs and submitted to the Analysis and Prediction Center of China Seismological Bureau, making China's earthquake observation technology in the forefront of the world.
Edit the working principle of this instrument.
There is an inverted long wooden vertebra in the seismograph, which has a high center of gravity and is in an unstable state, similar to an inverted beer bottle. The local seismic wave came, and the initial movement direction of the instrument base pointed to the epicenter and the opposite direction. Because of its own inertia, the direction of the falling of the wooden vertebra at this time points to the epicenter. The fall of the wooden cone triggered the lever in this direction, driving a faucet in this direction, and the faucet released the wooden beads in its mouth, thus indicating the direction of the epicenter. Seismographs cannot determine the distance and size of the epicenter. The explanation of the principle of seismograph now appears in a text in Book 4 of New Concept English. The title of the article is "Recording Earthquakes". How does a seismograph work? The easiest way to test earthquakes is to put small cylinders with different heights on a horizontal plane. When an earthquake happens, these cylinders will fall down. Different degrees of earthquakes will cause cylinders with different stability to fall down. That is to say, when the earthquake is not strong, only the most unstable cylinder will fall, while when the earthquake is strong, all cylinders will fall. This is just a simple method to test earthquakes, and it can't accurately record the fluctuations of earthquakes. Therefore, this testing tool needs further improvement. We know that when we write, the pen moves on the paper, leaving traces. On the contrary, if we keep the pen still and the paper moves, we can also leave traces on the paper. This principle can be used to record the fluctuation of earthquakes. Some people worry that the paper and pen are moving when the earthquake happens. How can we accurately record the movement of earthquakes? We can do a little experiment. Take a long thread (one meter is enough), tie a heavy object at one end of the thread, hold the other end of the thread with your hand, and hang the heavy object in the air, but keep the lower part of the heavy object just lightly touching the ground, and then gently swing the hand holding the thread back and forth, left and right, and you will find that the lower end of the heavy object hardly moves. The principle of this is inertia. One end of the line has moved conveniently, but one end of the heavy object remains in place due to inertia. Maybe moving hands will affect the position of heavy objects, which is greatly weakened by long lines. Similarly, if we put paper under it and write with a pen instead of a heavy object, we can record the fluctuation of the earthquake. In fact, in order to record more accurately, a paper ring rotating with the wheel can be used instead of flat paper, so that when the earthquake does not occur, the pen will leave a straight line on the paper, and when the ground fluctuates vertically, it will leave a wavy record on the paper. However, the problem is that it is impossible to record fluctuations in the same direction as the straight line. However, multiple devices in different directions can weaken these shortcomings.
Edit the purpose of this instrument.
OYO McSEIS-SX is a portable and cost-effective 24-channel or 48-channel seismograph, which can be used for refraction exploration, reflection exploration, in-well PS logging and cross-well seismic, and used for engineering shallow seismographs.
Architecture. The instrument integrates PS logging operation menu, and the PS logging data can be obtained by using BHP (model BHP(33 15) three-component detector. The whole system has compact structure, light weight and convenient transportation. The smaller 12V DC battery is used to work anywhere. Based on Windows XP SP2 Professional Edition, XGA/TFT color display, hard disk drive and USB2.0 port, the field operation quality is higher and the performance is more reliable and stable.
Edit the technical parameters of this paragraph.
Number of acquisition channels of PS logging data: 24+ 1 AUX or 48+2 AUX acquisition: up to 4 channels per gun (Hx, Hy, Vz, AUX). Each test mode: schematic diagram of digital components of mode channel: PS8VZ, HX+, HY+, HX-, HY-, AUXZ, AUX+, AUX-.
S+/S-6HX+, HY+, HX-, HY-, AUX+, AUX-P2VZ, AUXZ preamplifier gain:12,30,48 dB Frequency response: 2-4600Hz ADC resolution: 24-bit sampling interval: 33,50,48 dB. 1000, 2000, 4000μsec pre-trigger: 0, 128 sampling number data length: 1K, 2K, 4K, 8K, 16K/ channel trigger input: hammer switch (contact closed), geophone data storage:. And SEG2 system CPU: ULV Intel Celeron processor display: 10.42.5A (standby), 3A (maximum) working temperature: 0-45℃ Physical characteristics: 330 (width) x280 (depth) x 220 (height) mm Weight: 8kg.