The Earth’s crust is made up of tectonic plates which lie beneath both the solid surface and the ocean. The friction which is caused due to the sliding of these plates results in an earthquake. So, where is the centre of earthquake? In which point the first movement of an earthquake occurs? Let’s dive into this article and learn about an earthquake’s origin, movement, and repercussions.
1. What is the Centre of Earthquake called?
The centre of earthquake is known as the hypocentre. Commonly known as the focus of an earthquake, it is the actual point on the surface of the earth where the rupturing of the rocks begins. Hypocentres are located ten to a hundred kilometers below the surface of Earth. Therefore, in which point the first movement of an earthquake occurs? Hypocentre is the place where the waves originate and travel towards the outside in all directions. (See What are Geologic Features?)
2. What is the Movement of an Earthquake?
To identify the movement of an earthquake let’s first understand the tectonic plates. The Earth’s surface is broken and divided into large slabs and irregular pieces of rocks whose movement is the triggering point of an earthquake. Commonly known as ground motion, it is the movement of the earth’s surface that results from earthquakes and explosions. Sometimes the movement is deep underground and the surface does not break but at times, the movement is so forward and explosive that it breaks through the surface of the earth. (See How Convection Current causes the Lithospheric Plate to move?)
3. What is the First Movement of an Earthquake?
We understand that every earthquake has an initiating point, defined as the centre of earthquake. We just discussed the movement, however, it is not the first movement of an earthquake. The point or the focus at which the first movement occurs is called the earthquake’s hypocentre and the first motion which is the direction of the ground motion is called the P wave. The intensity of the movement and the seismic waves is measured using a seismometer. (See Why do buildings collapse during an Earthquake?)
4. Where do Earthquakes occur Where does it start?
When we talk about earthquakes an obvious question that comes to our head is, is there a specific area where most earthquakes occur? Are there some places where the frequency of occurrence of the earthquake is more in comparison to the others? If you have a close look at the patterns of earthquakes occurring, you will observe that the majority of these earthquakes are concentrated in some particular regions.
For example- over 80 per cent of large earthquakes occur around the Pacific Ocean. The earthquake starts below the surface of the earth at a point known as a hypocentre and its location is above the surface of the earth on the epicenter. (See How are Earthquakes distributed on the map?)
5. In which Point the First Movement of an Earthquake occurs?
The major question of today, however, still remains unanswered viz, in which point the first movement of an earthquake occurs? The first movement of an earthquake is felt at the focus point which is also known as the hypocentre. Here, after the movement of tectonic plates, energy in the form of seismic waves is released which travels upwards towards the surface of the earth and causes severe damage to life and property. (See What landform is created when two continental plates collide?)
6. Where does the Movement of an Earthquake come from?
Previously in the article, we got to know that earthquakes happened due to the movement of tectonic plates. But how does this movement happen? The Earth’s surface is made up of irregular plates and the plates contain belts of huge rocks. Earthquakes happen when there is a sudden slip between two rocks, there is a rapid motion that releases seismic waves and makes the ground shake. Also, check out Where is the Youngest and Oldest Crust?
7. What is Focus and Epicenter?
We have been hearing the words focus and epicenter right from the time and we learned about the movement of an earthquake, however, what do they signify?
- Focus, most commonly known as the hypocentre, is placed inside Earth’s crust which marks the origin of an earthquake. The energy released here makes the earth’s surface shake.
- Epicenter on the other hand is a point on the Earth’s surface vertically right above the focus.
8. Which Point marks the Epicenter of the Earthquake?
Epicenter is the point placed on the Earth’s surface directly above the hypocentre. So, in which point the first movement of an earthquake occurs? The hypocentre marks the point where the first movement of an earthquake occurs.
9. Why do P Waves come first?
The P waves cross the dense rocks which are placed deeper in the earth to come to the surface, hence they travel at a higher speed. The PP (one bounce) and the PPP (two bounce) cross through shallow rocks and hence take more time to reach. The shear waves, however, come after all P waves. (See What is the Difference between Oceanic Crust and Continental Crust?)
10. Where do Most Earthquakes occur?
We have acquired knowledge on the centre of earthquake and their movement but where do most earthquakes occur? The place where most earthquakes occur has earned itself the nickname Ring of fire. It encircles the Pacific seismic belt and is the world’s greatest earthquake belt. 80 percent of the largest earthquakes on our planet occur on the rim of the Pacific Ocean. (See What Country has the Most Mountain Belts?)
11. Where do Most Volcanoes occur?
Most of the volcanoes are found along the Ring of Fire belt which encircles the Pacific Ocean. Some of the islands like the Hawaiian island are known as hot spots.
Natural calamities that happen, be it earthquakes or droughts, etc. are a way of nature showing us the repercussions of not taking care of it. We need to be more careful while dealing with nature because when it backfires, there is a huge loss of life and property. This article walked you through the various movements and points of an earthquake, where does an earthquake start, and about different waves being generated. Hope this article was helpful and could satisfy your inquisitive minds. Now ask your friends, in which point the first movement of an earthquake occurs and see if they know the answer or not. (Also read How are volcanoes distributed on the map?)