What is a Seismograph?

A seismograph is an instrument that monitors the occurrence of an earthquake and records earthquake-related parameters. Zhang Heng, a scientist in the Eastern Han Dynasty in China, made the world's earliest "seismograph" in 132 AD-a geosynthetic instrument.

[dì zhèn yí]

Seismometer is a surveillance

The first true seismograph was invented in 1855 by Italian scientist Luigi Parmiri. It has a complex

There are mainly three types of seismometers used in seismic research, each of which has a period corresponding to the magnitude (speed and intensity) of the seismic vibration they will measure (the period refers to the length of time required for a pendulum to complete a swing, or Time required to swing once).

The recorded ground motion instrument launching principle is Shi Guanfa. The entire record says that Duzhu went to the eight roads to pass off. Duzhu is at the center of the ground motion instrument. It is a structured pillar inside. The so-called waiting air component is among them. The extension of the dental machine is called Guan, which is close to the wind-waiting components within eight channels. The gap between them is less than one millimeter. When the earthquake wave came, Hou Feng's parts swung to the off position to push off the movement to trigger the dental machine. Produces the result of machine vomiting. This is how it really works. The dental machine can do this when the seismic wavefront arrives. In theory, the sensitivity of the dental machine can be a geometric point. The other starting methods are not waiting for the wind.

The following statement is incorrect. Please pay attention to comparison reading.

The ground motion instrument has an inverted, long wooden vertebra with a high center of gravity, which is in an unstable state, similar to an upright beer bottle. When the seismic wave comes, the initial movement direction of the base of the instrument is directed towards the epicenter, and in the opposite direction. Due to its own inertia, the direction in which the vertebra fell down at this time was pointing to the epicenter. The fall of the wooden vertebra triggers a lever in this direction. The lever drives a dragon head in this direction. The dragon head releases the wooden beads in the mouth, which indicates the direction of the epicenter.

The ground motion meter cannot determine the distance and magnitude of the epicenter.

An explanation of the principle of the seismograph appears in a text in Book IV of the New Concept English. The title of the article is "Recording the Earthquake". So how does a seismograph work? The roughest way to test an earthquake is to place small cylinders of different heights on a horizontal plane. These cylinders will fall when an earthquake occurs. Different degrees of earthquakes can cause cylinders of different stability to fall. That is, when the earthquake is not strong, only the most unstable cylinders fall, and when the earthquake is strong, all the cylinders fall. This is just a simple method for testing earthquakes, and it is impossible to accurately record the fluctuations of earthquakes. Therefore, this test tool needs further improvement.

We know that when we write, the pen moves on the paper, leaving a trail. Conversely, if we keep the pen still and the paper moves, we can also leave marks on the paper. This principle can be used to record the fluctuations of an earthquake. Some people are worried that when the earthquake occurs, the paper and pen are moving. How can you accurately record the movement of the earthquake? We can do a small experiment. Take a long line (one foot foot), attach a weight to one end of the line, hold the other end of the line with your hand, and suspend the weight in the air, but keep the lower part of the weight just touching the ground gently, and then lightly With a light, forward, backward, left, right, and left swinging hand holding the line, you will find that the low end of the weight will hardly move. The principle is inertia. One end of the line has been moved with the movement of the hand, but one end of the heavy object remains in place due to inertia. Maybe a moving hand has an effect on the position of the weight, and this effect has been greatly weakened by long lines. By the same token, if we place the paper underneath and replace a heavy object with a writable pen, we can record the fluctuations of the earthquake.

In fact, in order to record more accurately, the tiled paper can be replaced with a paper ring that rotates with the wheel. In this way, when the earthquake does not occur, the pen will leave a straight line on the paper, and the ground surface will undergo this vertical fluctuation. As a result, a wavy record is left on the paper. However, the problem is that fluctuations in the same direction as a straight line cannot be recorded. However, multiple devices in different directions can mitigate these disadvantages. With the development of science, these problems have been solved.