History of Seismology

Our world is home to several beautiful wonders of nature, including the tall mountains, green forests, vast oceans, and many more. Besides these magnificent sceneries, our planet also has incredible natural occurrences, which is essential in sustaining human life.

However, among the natural occurrences here on Earth, some have a destructive force that destroys landmasses, including their structures – and could also take the lives of humans. Earthquakes are one of the natural occurrences that could cause destruction to the land.

Earthquakes, as we all know it, are movement or shaking of the surface of our planet. This movement generates energy from the Earth’s lithosphere, which results in seismic waves. We often see and hear about earthquakes from the news, along with other information related to it, such as size and strength.

Moreover, some earthquakes in history generated a tremendous amount of power that caused several casualties. Included in the list is the Great Chilean earthquake, which is often considered as the most powerful ever recorded. The power of the earthquake varies from 9.4 to 9.6 on the moment magnitude scale. The incredible power of this earthquake resulted in roughly 7,000 people killed and billions of dollars worth damages.

Interestingly, scientists developed a way to study earthquakes in a branch of Earth science called seismology.  In this article, we are going to look into what exactly is seismology, and what its history is.

What is Seismology?

Seismology is a branch of Earth science devoted to the scientific study of earthquakes. It also focuses on understanding the propagation of elastic waves through the Earth. Furthermore, this field of science does not only study earthquakes but also the environmental effects it brings, such as tsunamis. In contrast to this, seismology also gains an understanding of the various seismic sources, including volcanic, tectonic, glacial, fluvial, oceanic, and many others.

The scientists who work in this field are called seismologists. They often use various tools to help them identify and detect seismic activities on the planet. One of the most common tools they use is seismometer and seismogram. These tools are used to help record and detect the Earth’s motion caused by elastic waves.

What is the origin of seismology?

We can trace back the origins of seismology to thousands of years ago. Similar to other branches of science, the study of earthquakes dates back to ancient Greek from the works of the early great philosophers, such as Thales of Miletus, Anaximenes of Miletus, and Aristotle. Their work was not yet considered as seismology since science was not yet developed at that time. It merely consisted of speculations about the natural causes of earthquakes, which sparked the interest to other philosophers and scientists.

Years later, a breakthrough in the development of seismology was made by Zhang Heng of China in 132 CE. Experts consider Zhang Heng as the designer of the first known seismoscope. His design consists of a jar-shaped vessel surrounded by eight tubes shaped like a dragon, along with each dragon is a bronze ball atop a mouth shaped like a toad.

Zhang Heng designed the seismoscope to drop the ball to whichever direction it felt the earthquake, and at the bottom was a mouth of a toad ready to catch the ball. This early design of the seismoscope was far from the tools that we have in our modern world, although it did help in the development of seismology over the years.

Fast-forward to the 17th century when the development of seismology was gradually improving. During this time, many theories and speculations were made about the causes of earthquakes. Some thought includes; earthquakes were a product of the movement of fire within a system of channels inside our planet.

During the mid-19th century, the Irish geophysicist, Robert Mallet, made a significant impact on the advancement of seismology. Experts consider him as the person to have laid the foundation of instrumental seismology. His works consisted of several observations about the movement of the ground, mainly through the help of explosives. His experiments carried out excellent results, which remarkably helped in gaining further understanding of earthquakes. Furthermore, Mallet is also responsible for coining the term ‘seismology,’ which is widely known today as the study of earthquakes.