KOMPAS.com – Earth’s tectonic plates are one of the factors that often trigger earthquakes in most regions of the world.
Especially in countries whose territory is on the line of tectonic plates. Like Indonesia, most of whose territory lies along the Indo-Australian plate and the Eurasian plate.
The formation of tectonic plates is inseparable from the history of the Earth in the past. Billions of years ago, the Earth’s surface was a sea of molten rock.
As this boiling magma gradually cools, it forms a continuous rocky shell, with denser minerals fusing into the planet’s interior and less dense minerals rising to the surface.
“That’s how plates form on the Earth’s surface,” said Catherine Rychert, a geophysicist at the Woods Hole Oceanographic Institution in Massachusetts.
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“Plates are the earth’s crust and then a little mantle beneath it, as well as softer material,” he added.
The material in the Earth’s plates is hotter and moves more easily. The difference in strength between these layers allows the overlying plates to move, collide, and diverge.
In this zone, rifts and mountains are formed, as well as volcanoes and earthquakes that trigger life.
Number of Earth’s tectonic plates
However, how many tectonic plates actually cover the Earth’s surface?
Quoted from Live ScienceThursday (12/10/2023) it is estimated that the number of tectonic plates on this planet ranges from a dozen to almost 100 plates.
Most geologists agree that there are between 12 and 14 “primary” tectonic plates covering most of the Earth’s surface.
Each of these tectonic plates has an area of at least 20 million square kilometers, with the largest being the North American, African, Eurasian, Indo-Australian, South American, Antarctic and Pacific plates.
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geo.libretexts.org Tectonic plates that make up the Earth’s surface and cause tectonism
However, the most monumental is the Pacific Plate, which covers an area of 103.3 million square km, followed by the North American Plate, which covers an area of 75.9 million square km.
“Apart from the seven very large plates, there are five other smaller plates, namely in the Philippine, Cocos, Nazca, Arabian and Juan de Fuca Seas,” explained Saskia Goes, a geophysicist at Imperial College London.
Some geologists count the Anatolian Plate (part of the Eurasian Plate) and the East African Plate (part of the African Plate) as separate entities.
But things get more complicated when looking at plate boundaries, where plate tectonics causes plates to break apart into smaller fragments called microplates.
These microplates cover an area of less than 1 million square km and some scientists estimate there are around 57 of them on Earth.
However, these microplates are not included in the world map.
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“The number of microplates will continue to change, depending on how scientists choose to define them, and as we learn more about how and where deformation occurs at plate boundaries,” Goes said.
As geologists understand this dynamic puzzle, the movement of Earth’s plates creates some interesting scenarios.
For example, what happens on the Pacific Plate. The plate with the fastest movement is heading northwest at 7 to 10 cm per year.
“This rapid movement is caused by the surrounding subduction zone ring, otherwise known as the Ring of Fire, where gravitational forces pull the plates into the Earth,” explained Rychert.
Given the power of this movement, what our planet’s surface will look like in the future is still a mystery. It is possible that plate movements can cause a continent to disappear.
Also read: How many meteorites hit the Earth every year?
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2023-10-15 02:30:00
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