Earthquake vs Aftershock
Earthquake and Aftershock are classification of the tremors that come in clusters in the event of an earthquake. Earthquakes are natural calamities of great magnitude that bring devastation of huge scale in their wake. Sometimes, small tremors are felt for days before the large or main earthquake strikes an area. These tremors, mild or strong are referred to as foreshocks. In a similar manner, it is common for a place that has bore the brunt of a huge earthquake to experience smaller tremors for days to come after the earthquake. These tremors are referred to as after shocks. People are often confused as to what the difference between earthquake and aftershock is, and for the victims, aftershocks are often as devastating, in particular psychologically. This article will clarify the differences, as well as features of both an earthquake to make people better informed about this natural disaster.
Earthquake
Earthquakes are sudden and huge tremors that result because of release of seismic energy from below the earth’s crust. These quakes take place without any warning in all parts of the world but some places are geographically more prone to earthquakes than others as is proved by the frequency of earthquakes taking place in these places in the past. Earthquakes occur mostly because of rupture of geological faults, but also take place because of volcanic activities and landslides. Some earthquakes are a result of activities of mankind such as mining and nuclear testing. The point where rupture takes place is called the focus or hypocenter of the earthquake whereas epicenter refers to a place just above this hypocenter at the ground level.
The magnitude of an earthquake is measured through Richter magnitude scale and is assigned a value of 1-9 on the scale with increasing value referring to an earthquake of greater proportions. In general, the more shallow an earthquake, the more devastation it can cause on the surface of the earth.
Aftershock
As described earlier, earthquakes normally come in clusters that are classified as foreshocks, main earthquake and aftershocks. In general, after shocks are also earthquakes but of minor magnitude thus causing less or no damage, but there have been instances where aftershocks were of a greater magnitude thus being called as the mainshock later on. Thus it is clear that all these shocks are related to each other. As a general rule, an aftershock must take place after the main event called the earthquake, within one rupture length of the original fault rupture.
Based upon past experiences, people expect aftershocks after the main earthquake, and this is the big difference between earthquake and aftershocks. There is no way to anticipate an earthquake, but people are mentally prepared for the aftershocks. In general, the frequency and number of aftershocks decreases with passage of time after the earthquake. Aftershocks are more frequent within the first few hours of the earthquake and nearly half of the aftershocks are felt within hours of the earthquake. It has been observed that the magnitude of the after shocks is also dependent upon the magnitude of the earthquake. So if the earthquake has been of a great magnitude, the largest aftershock will also be of great magnitude.
In general, though aftershocks are similar in nature to earthquakes, they, despite not as strong as earthquake can still cause damage of property and lead to loss of lives even.