Related topics: quake · earth · earthquake · geologists · earth sciences

Slow start of plate tectonics despite a hot early Earth

Writing in PNAS, scientists from Cologne university present important new constraints showing that plate tectonics started relatively slow, although the early Earth's interior was much hotter than today.

Secret of Australia's volcanoes revealed in new study

Australia's east coast is littered with the remnants of hundreds of volcanoes—the most recent just a few thousand years old—and scientists have been at a loss to explain why so many eruptions have occurred over the past ...

Researchers discover 'missing' piece of Hawaii's formation

An oceanic plateau has been observed for the first time in the Earth's lower mantle, 800 kilometers deep underneath Eastern Siberia, pushing Hawaii's birthplace back to 100 million years, says a Michigan State University ...

Former piece of Pacific Ocean floor imaged deep beneath China

In a study that gives new meaning to the term "rock bottom," seismic researchers have discovered the underside of a rocky slab of Earth's surface layer, or lithosphere, that has been pulled more than 400 miles beneath northeastern ...

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Plate tectonics

Plate tectonics (from the Greek τέκτων; tektōn, meaning "builder" or "mason") describes the large scale motions of Earth's lithosphere. The theory encompasses the older concepts of continental drift, developed during the first decades of the 20th century by Alfred Wegener, and seafloor spreading, understood during the 1960s.

The lithosphere is broken up into what are called tectonic plates. In the case of Earth, there are currently eight major and many minor plates (see list below). The lithospheric plates ride on the asthenosphere. These plates move in relation to one another at one of three types of plate boundaries: convergent, or collisional boundaries; divergent boundaries, also called spreading centers; and transform boundaries. Earthquakes, volcanic activity, mountain-building, and oceanic trench formation occur along plate boundaries. The lateral movement of the plates is typically at speeds of 50–100 mm annually.

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