How many tectonic plates does the Earth have?

The Earth has between 10 and 100 tectonic plates, and most of them don't even appear on official maps.

Large and small tectonic plates on the Earth's surface. Photo: iStock

Billions of years ago, the Earth's surface was a sea of ​​molten rock. As the magma cooled, it formed a continuous crust of rock with denser minerals accumulating near the planet's core and less dense minerals rising to the surface. According to Catherine Rychert, a geophysicist at the Woods Hole Oceanographic Institution in Massachusetts, this is how tectonic plates form on the Earth's surface. A tectonic plate is a layer of crust with a small mantle underneath. Beneath it is weaker, hotter, and more mobile material. The difference in density between the two layers causes the layers above to shift, collide, merge, and crash into each other. In these areas, faults and mountains formed, volcanoes and earthquakes led to the emergence of life.

The number of tectonic plates covering the Earth's surface ranges from a dozen to nearly 100, depending on the classification criteria. Most researchers agree that 12-14 major tectonic plates cover the majority of the Earth's surface, according to Saskia Goes, a geologist at Imperial College London. Each plate covers at least 20 million square kilometers, with the largest being the North American, African, Eurasian, Indo-Australian, South American, Antarctic, and Pacific plates. The largest of these is the Pacific plate, spanning 103.3 million square kilometers, followed by the North American plate with an area of ​​75.9 million square kilometers.

According to Goes, in addition to the seven major tectonic plates, there are five smaller plates: the Philippine Sea, Cocos, Nazca, Arab, and Juan de Fuca. Some geologists consider the Anatolian plate (part of the larger Eurasian plate) and the East African plate (part of the African plate) as separate entities because they move at significantly different speeds than the main plate. This is why the number of major tectonic plates is between 12 and 14.

The situation is more complicated when considering tectonic plate boundaries, where they divide into smaller plates called microplates. Microplates are areas less than one million square kilometers in size. Some scientists estimate there are around 57 microplates on Earth. But they are not usually shown on world maps. "The number of microplates is constantly changing, depending on how scientists define them differently and the deformation at tectonic plate boundaries," Goes explains.

The Earth's moving tectonic plates create some remarkable structures. The Pacific Plate may be the fastest, moving northwest at a rate of 7–10 cm/year. Its rapid movement results from the surrounding subduction zone, also known as the Ring of Fire, where gravity pulls the plate toward the Earth's center.

An Khang (According to Live Science )

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