Seismology

Every year almost 20,000 earthquakes occur in the world and do you know it is one of the most unpredictable natural disasters that causes a lot of damage wherever it occurs. You must be thinking that it should be studied properly to know why and how it occurs and how we can save ourselves from this. Well, there is a separate branch of study that deals with this part comprehensively and deals with every aspect related to it. This is an interdisciplinary field of study which has a long history and that got contributions from various Mathematicians, Physicists, Geologists, Engineers, inventors, etc. Let's study it in this article. It will help you in understanding one of the major disciplines and getting a basic knowledge about it.

Study of Earthquake - An Introduction

If we dig into a particular concept deeply then it becomes a separate study field, for example, if we study climate it will be called climatology, when we study land, it becomes geomorphology, etc. Have you ever wondered what it will be called when we study earthquakes? 

If we talk about earthquakes first then the sudden movement or shaking of the earth's crust whose early warning is difficult and also can occur at any time and any place mostly due to natural reasons but sometimes also occurs due to man-made activities, then this is known as earthquakes and when we study the earthquakes, it is called as seismology and the one who studies it will be called a seismologist. 

Seismology Meaning

It is a separate branch of Geology or Science that deals with earthquakes. It is a scientific and interdisciplinary subject that studies earthquakes and their related concepts. This term is made up of two words ie. Seismos means earthquake and logy mean study. Thus, this term refers to the study of earthquakes. Robert Mallet who was a geophysicist, inventor, and engineer is considered the father of seismology because of his great research in this field.

The energy flows under the Earth in the forms of some waves which are known as seismic waves and seismology studies these waves. These waves not only help in understanding and predicting earthquakes but also helps in understanding the composition and internal structure of the Earth which is complex but has become much easier to understand its structure because of the distinct nature of the passing of these waves through different surfaces. The two major types of these waves are P waves and S waves. The former can be passed through solid, liquid, and gaseous material whereas the latter can only pass through the solid surface.

Definitions

• The basic definitions are " study of earthquakes " or  " study of seismic waves ".

• According to the Cambridge dictionary, " it is the scientific study of the sudden, violent movements of the earth connected with earthquakes."

History of Seismology

Its history can be traced back to 4,000 years ago whereas the quest to learn the natural causes of earthquakes by man actually started only 26 centuries ago. This concept gained a global look in the year 1889 when the first time teleseismic record was done and a seismograph was developed. It was the time when seismology was seen as a separate global science. Its birth happened in 1889 but its origin actually began on Nov 1, 1775, with the Lisbon Earthquake, which was considered as the major event that entirely changed our outlook towards this naturally occurring event. Various mathematicians, physicists, engineers played a great role in this. Thus, it is an interdisciplinary science that can not be separated entirely from the history of continuum mechanism, applied mathematics, and general wave theory. The event of 1889 was considered as the first revolution in this field whereas the second revolution occurred when initial computers were introduced in 1950 - 1955 in this field. 

Series of Contribution

Some of the earliest major contributions in this field are mentioned below:

• Aristotle ( ca. 340 B.C.E ) was considered as the first person who tried to give an explanation of earthquakes and classified them into 6 types.

• Seismoscope was invented by a Chinese scholar namely Chang Heng. It is considered the earliest known instrument in this regard.

• The earliest work in this field was from England of Robert Hooke's " Discourse on Earthquakes " ( 1667 to 1697 ).

• John Mitchell who was a Geology professor at Cambridge University was the first who declared the fact that " earthquakes originate within the Earth ".

• The first-ever seismometer was designed by James David Forbes in the year 1841.

• The first-ever recording was done in Japan by John Milne in 1880 but it could record only local earthquakes and the first ever recording that got a global sense was done by Ernst von Rebeur Paschwitz in 1889.

• The first-ever electromagnetic seismograph along with photographic recording was designed in 1906 by Boris Borisovich Golitzin.

Famous Seismologists

The person who studies and works in the discipline of seismology is known as Seismologists. Basically, he is the one who studies earthquakes and seismic waves. Some of the notable seismologists are John Michell, Charles F. Richter, Clarence Edward Dutton, John Milne, Harry Fielding Reid, Richard Dixon Oldham, and Beno Gutenberg, etc.

Seismic Instruments 

Some of the major seismic tools and instruments are used by the seismologist while studying this discipline such as seismometers, seismographs, and seismograms. Among these, the motion of the ground on the Earth can be recorded by a seismograph during the occurrence of an earthquake. They are installed basically at different locations of the Earth to record the movements that cause earthquakes and works as a seismic network. If we talk about a seismometer, it is a part of the seismograph only whereas the ground movement and shaking of a specific location are recorded with a seismogram. Besides these, seismologists also use various scales such as the Richer scale, the Mercalli scale, and the Moment Magnitude scale. Here, the first one the earthquakes on a scale of 1 to 10 and the second one on a scale of 1 to 12 whereas the third one is nothing but a successor of the first one.

Did you know?

Around 80% of the total number of earthquakes occurred in the region which is generally known as the " Ring of Fire " and this region is a home of almost 452 volcanoes which is also more than 75% of the world whereas if we talk about the largest earthquake ever recorded in the world, then it was occurred on May 22, 1960, with a magnitude of 9.5 in Chile.

Conclusion

Thus, here we have covered and learned about a separate branch of science that deals with one of the most important concepts related to the Earth. It has extreme importance because of the occurrence of several numbers of earthquakes on the Earth every year and it is very important to understand this concept more clearly so that we can deal with it. We have comprehensively covered the seismology meaning, history, and origin of the seismology here. We believe that with this article you have got basic knowledge of this subject and you will get more knowledge about its related concepts like earthquakes and seismic waves, etc. 

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