Approximately 1.3 million earthquakes occur each year, without taking into account those that humans are aware of as being of very low intensity. Difference Between Seismograph and Richter Scale
Most of these earthquakes occur in remote areas, far from people and there are many reasons why they occur; from meteorites , volcanic eruptions, man-made events, underground nuclear tests or, more often than not, the shifting of Earth’s tectonic plates.
In spite of everything, more than the cause of earthquakes, the important thing is to know their magnitude or intensity, the damage they can cause and how to act when they occur. To achieve these purposes there are two very useful instruments: the seismograph and the Richter scale. Here we explain how they differ.
The seismograph is an instrument that measures the movements of the earth, that is, the seismic waves generated by earthquakes, volcanic eruptions and other sources. Seismic wave logs help seismologists map the interior of the earth, locate and measure different sources of earthquakes.
The first seismograph was designed by Zhang Heng of the Han Dynasty of China in 132 AD. It was called “Houfeng Didong Yi”, which literally means “an instrument for measuring seasonal winds and movements of the earth.”
The original plans for Zhang Heng’s seismometer (as the seismograph is also called) were lost over time. However, historians and scientists were able to retrieve enough information to create a model. After 1880, most seismometers were descendants of those developed by the team of John Milne, James Alfred Ewing, and Thomas Gray, who worked in Japan from 1880 to 1895. After World War II, these seismometers were again adapted.
This instrument has a weight hanging from a spring , therefore, it is sensitive to the movements of the earth. Changes in motion that are recorded by this device can help indicate the probability of an earthquake occurring. S owever, this creates another problem How to properly describe the intensity of the earthquake once it occurs?
This scale is the one used to measure the intensity of earthquakes. Thus, depending on how intense they are, they are assigned a number ranging from 1 to 10, where 1 is very low intensity and 10 is very high.
It was developed by Charles Francis Richter, in collaboration with Beno Gutenberg in 1935. Or was it to be used only in one study area located in California, however, eventually the scale became an accepted standard around the world.
The Richter scale assigns a number based on how much energy is released during the earthquake. It is a logarithmic scale of base 10, which means that an earthquake that measures 5.0 on the Richter scale, has an intensity 10 times greater than one that measures 4.0.
Although it goes from 1 to 10, the reality is that this scale does not have a lower limit. Many modern seismographs that are quite sensitive, record earthquakes with incredibly low magnitudes.
Key differences between seismograph and Richter scale
- The seismograph is an instrument that measures the movement of the earth, while the Richter scale was developed to assign a numerical value or quantify the energy released during an earthquake (intensity).
- The Richter scale was developed in 1935, while the seismograph was developed in 132 AD.