Natural disasters are a part of Earth’s internal processes. Whether it be the 2011 Tohoku Earthquake and Tsunami in Japan or the 2020 Australian Bushfires, natural disasters are a cause of trauma for humanity. Earthquakes are one such natural disaster. Earthquakes are the kind of natural disaster that, depending on their magnitude, may pass unnoticed or collapse buildings and cause tsunamis. In this article, you will learn how are earthquakes distributed on the map. Also, you will get to know whether earthquake distribution is uniform and where earthquakes usually occur.
1. What are Earthquakes?
At the Earth’s center, there is a core. These layers are the mantle and crust. The mantle, the middle layer, is a mostly-solid layer upon which the crust lies. On the other hand, the crust is the 40 km deep layer upon which the surface we interact exists. An earthquake is a natural event during which the Earth’s surface violently shakes. This shaking is a result of the movement of tectonic plates.
Tectonic plates are constituent parts of solid that make up the layer below the crust. The tectonic plates float on the mantle, which sometimes flows, and most earthquakes result from the interaction between two or more plates which is related to how are earthquakes distributed on the map. (See What are the 6 Layers of the Earth?)
2. How do Earthquakes occur?
Earthquakes are natural disasters that occur due to the Earth’s internal processes. The movement of tectonic plates, also known as tectonic shift, is the primary reason for earthquakes. Interaction between two or more of these tectonic plates causes earthquakes. As such, the following are the four common reasons that earthquakes generally occur:
- Tectonic Plate Divergence: Earthquakes occur when two or more tectonic plates engage in divergent motion, moving away from one another. It occurs due to the flow of the tectonic plates in opposite directions.
- Tectonic Plate Convergence: When two or more tectonic plates engage in convergent motion, meaning they move towards one another, earthquakes occur. It occurs due to the flow of tectonic plates towards the same point between them.
- Tectonic Plate Rupture: When two tectonic plates rub against one other, the resulting friction causes Earthquakes.
- Volcanic Eruptions: When a volcano erupts, it pushes the magma from the Earth at high pressure. This pressure and heat usually cause earthquakes. Also, check out how convection current causes the Lithospheric Plate to move?
3. What is an Epicenter of an Earthquake?
You can comprehend the origin of an earthquake by understanding two of its crucial components which are the hypocenter and epicenter.
- The hypocenter is where the earthquake originates. It lies underneath the surface. It is the point from which the earthquake reaches the surface.
- The point of contact between the surface and the earthquake is the epicenter. The epicenter is the central focal point of an earthquake where it is the most intense.
4. How is the Epicenter of an Earthquake distributed?
To understand how epicenters distribution happens on a map, we need to answer the question: how are earthquakes distributed on the map? Earthquakes are distributed along fault lines, the boundaries of tectonic plates. As the epicenter is inseparable from the earthquake itself, epicenter distribution is the same as earthquake distribution. Earthquakes result from interactions between tectonic plates and therefore occur along fault lines. Similarly, the epicenters of earthquakes also occur along the fault lines. Must read what is the difference between Oceanic Crust and Continental Crust?
5. Where do Earthquakes occur?
There are certain necessary conditions for an earthquake to occur. Usually, the regions where earthquakes occur exist along the boundaries of the tectonic plates or fault lines. These regions are dependent on the size of the tectonic plate. The crust has seven major tectonic plates and several minor ones. These regions usually occur in four areas:
- The borders of continents
- Island groups
- Some underwater regions
- Volcanic regions. (See How are Typhoons formed?)
6. Does Earthquake occur Everywhere?
No, earthquakes do not occur everywhere. The distribution of earthquakes is uneven across the world. How are earthquakes distributed on the map has everything to do with the interrelation between earthquakes and tectonic plates. As tectonic plates enclose parts of the surface, these areas are less likely to experience tremors. Apart from fault lines, earthquakes also occur alongside volcanic eruptions. Therefore, we conclude that earthquakes do not happen everywhere they occur in specific areas around fault lines or volcanic regions. (See Why do people live near Volcanoes?)
7. How are Earthquakes distributed on the Map?
On the map, we see clear trends in the distribution of earthquakes. As we have established, for an earthquake to occur, it needs to be in a region surrounding the fault lines. Therefore on a map, earthquake distribution occurs along the tectonic plate boundaries. These boundaries usually fall near the borders of continents, through island groups, or underwater. In close relation to volcanic activity, we also see that earthquakes accompany volcanic eruptions. Hence, earthquake distribution also coincides with volcano distribution. (See Is the Eye of a Hurricane Calm?)
8. Are Earthquakes distributed evenly on the Map?
How are earthquakes distributed on the map: evenly or unevenly? To understand the answer, it is necessary that we first understand why and where earthquakes occur. The distribution of earthquakes generally takes place along the tectonic plate boundaries. Earthquakes themselves result from the interaction between two or more tectonic plates. The boundaries of the tectonic plates, or fault lines, are the areas where interaction between two or more plates becomes possible. This uneven distribution occurs along the boundaries of the 20 odd constituent tectonic plates in motion. Must read about the 8 sand storms facts.
9. Why is the Global Distribution of Earthquakes Uneven?
The global distribution of earthquakes is uneven due to the tectonic plates. So how are earthquakes distributed on the map unevenly? The tectonic plates that constitute the Earth’s crust differ in size. We can divide the tectonic plates into two types with surface area as the criteria for major (large) plates and minor (small) plates. On Earth, we live on seven major and several minor tectonic plates. Of the seven major tectonic plates, the Pacific plate is the largest. The uneven distribution of earthquakes is because of the varying locations and sizes of the constituent tectonic plates. (See What are the Northern Lights?)
10. Explain Earthquake Distribution Map?
How are earthquakes distributed on the map? The answer is simple, look at the boundaries of the tectonic plates that constitute the crust. Earthquake distribution occurs along these boundaries, or fault lines, where tectonic plates interact. Tectonic plates are the main constituents of the Earth’s crust, the crust that makes up the lithosphere. This classification takes place per the size of the plates namely major tectonic plates and minor tectonic plates. Earthquake distribution also witnesses another trend which is major tectonic plates are less likely to experience earthquakes than minor tectonic plates. (See Shipwrecks In The Ocean)
11. How are Volcanoes Distributed on Map?
Besides, how are earthquakes distributed on the map the distribution of volcanoes is similar to earthquake distribution and is specific to regions. The consensus is that volcano occurrences are not random across Earth. The Theory of Plate Tectonics supports this idea by presenting the trends of volcano generation.
Following the Theory of Plate Tectonics, you can see that volcanoes occur, in a general sense, along fault lines or tectonic plate boundaries. However, the locations of the fault lines fall into three broad categories: the edges of continents, island groups, and underwater regions. Interestingly, volcano distribution coincides with earthquake distribution owing to the similar conditions they require. To know more about it, check the article How are Volcanoes Distributed on the Map?
12. What is the Global Distribution of Earthquakes and Volcanoes?
As for volcanoes, there are about 1350 volcanoes in the world. All of those volcanoes are those that have the potential to be active. This number, however, excludes the belts of volcanoes that exist underwater. As for earthquakes, we record about 20,000 earthquakes a year. It means that daily we can record about 55 earthquakes. (See How many Tornadoes in Tennessee per year?)
13. Why Distribution of Earthquakes coincides with the Distribution of Volcanoes?
Seismic (earthquake) and volcanic activity are interrelated. It is frequent for earthquakes and volcanoes to occur along the boundaries of tectonic plates. Earthquakes can cause volcanic eruptions forcing magma out to the surface, and volcanic eruptions, in turn, can cause earthquakes due to the outflow of magma. Therefore, the distribution of volcanoes on a map coincides with how earthquake distribution takes place on a map. (See What Layer of the Earth does Magma come from?)
14. Where do most Earthquakes and Volcanoes occur?
As you have previously established, the distribution of earthquakes and volcanoes is not uniform across the Earth.
- The largest number of earthquakes occur in Japan. Japan ranks on top due to the density of seismic activity.
- Speaking of the volume of total earthquakes, Indonesia ranks higher as it covers more area in a seismic zone than Japan.
- The most volcanoes exist in the US at 161. However, there are only 63 active volcanoes in the US.
- The highest number of active volcanoes is in Indonesia at a staggering 74. Also, check out Top 10 Major Mountain Ranges of the World)
Most earthquakes and volcanoes occur near the edges of the tectonic plates. Speaking of how are earthquakes distributed on the map and volcano frequency, one cannot help but mention the Ring of Fire. The Ring of Fire is a region in the Pacific Ocean where there is an abundance of volcanoes. There are constant eruptions and accompanying earthquakes in this region. It makes the Ring of Fire an inaccessible area in the Pacific Ocean and a dangerous one. (See How do Mountains affect Dry Areas like Nevada?)