The Nature and Frequency of Earthquakes
An earthquake refers to the sudden energy release within the Earth’s crust. This energy release induces seismic waves, which, in turn, make the Earth tremble. From time to time, earthquakes occur in different parts of the world. They cause deaths and massive loss of properties. This has led to the development of extensive research on the menace. However, it depends on the nature of these earthquakes. Seismic activity of a geographical area refers to the type, size, and frequency of earthquakes experienced during a given time period. This also forms the basis of this research. The essay seeks to understand the nature of earthquakes as well as the frequency of their occurrence.
As mentioned above, earthquakes are caused by energy release beneath the Earth’s surface. The measurement of earthquakes is done by the use of seismometers. The most common scale for measuring earthquakes is the moment magnitude. The energy release causing earthquakes could emanate from different sources. First, it is vital to mention that human activities can also induce earthquakes. However, the natural causes are the most catastrophic. Therefore, they will form the basic explanation of the nature of earthquakes. One natural process that leads to earthquakes is the movement of blocks of the Earth’s crust past each other. When there is a fault line between two blocks, the strin energy tends to cause them to move past each other. However, there may be irregularities and asperities along the faults. This hinders the relative movement of the two, but the strain energy is still present; therefore, the movement is still forced. When the stress increases to a certain level, the asperities crack, and sudden movement occurs. This leads to energy release, which, in turn, causes earthquakes. Other activities that may cause such energy release are tidal forces, volcanic activities, strains in plate boundaries, and human activities. The point where the energy release occurs is called the seismic focus. There are shallow-focus and deep focus earthquakes depending on how deep the seismic focus is placed ( Prager, 2000).
Depending on the magnitude of earthquakes, they cause varied levels of damage to the areas in which they occur. Therefore, it is vital to review their frequency of occurrence. According to research, around 500,000 earthquakes take place every year. They can be detected by the existing instrumentation. Of all these, only 100,000 can be felt. The occurrence of minor earthquakes is experienced in many places around the world. These places include Mexico, Chile, California, Alaska, Iran, Turkey, Portugal, and many other countries. However, it is important to note that they can occur anywhere in the world. Earthquakes with larger magnitudes occur lless frequently than those with lower ones. For example, in the UK, which is a low seismic area, earthquakes of a magnitude of 3.7- 4.6 occur every year. In the same region, earthquakes of 4.7- 5.5 occur once in ten years. Earthquakes of higher frequency than this occur once in 100 years. This is the same case for most geographical areas in the world. This is the reason as to why the occurrence of catastrophic earthquakes may be hard to predict. However, researchers always have a clue of their occurrence due to advanced research. The number of seismic stations has increased from the past 350 to 1931(Stewart, 1994).. Therefore, more earthquakes are recorded and patterns of the same determined. This means that there is a possibility for the experts to always have a clue when an earthquake is about to occur. This is the reason as to why they always issue warnings before the occurrence of earthquakes. The people who give heed to the warnings issued end up saving their lives.
This essay is a small, but detailed explanation of the nature and frequency of earthquakes. It provides an overview of how earthquakes can be analyzed. This is the kind of information that researchers use to predict the possibility of the occurrence of earthquakes anywhere in the world. Therefore, it is vital information, which can be used to save numerous lives as well as property in the affected areas.