subduction

American  

[suhb-duhk-shuhn] / səbˈdʌk ʃən /

noun

1. an act or instance of subducting; subtraction or withdrawal.

2. Geology. the process by which collision of the earth's crustal plates results in one plate's being drawn down or overridden by another, localized along the juncture subduction zone of two plates.

---

subduction British  

/ səbˈdʌkʃən /

noun

1. the act of subducting, esp of turning the eye downwards

2. geology the process of one tectonic plate sliding under another, resulting in tensions and faulting in the earth's crust, with earthquakes and volcanic eruptions

---

subduction Scientific  

/ səb-dŭk′shən /

1. A geologic process in which one edge of one lithospheric plate is forced below the edge of another. The denser of the two plates sinks beneath the other. As it descends, the plate often generates seismic and volcanic activity (from melting and upward migration of magma) in the overriding plate.

2. Compare obduction

---

Etymology

Origin of subduction

1570–80; < Latin subductiōn-, stem of subductiō pulling up, computation; see subduct, -ion

Explanation

In geology, subduction is what happens when one tectonic plate moves underneath another. Most strong earthquakes are caused by subduction. Subduction causes the most powerful earthquakes, and over time it's also what creates volcanoes and mountains. When you study geology or earth science, you'll learn about areas of the earth called "subduction zones," regions where subduction is occurring and earthquakes are relatively common. Before 1970, the word was used to mean "removal of noxious substances from the body."

Example Sentences

Two major fault systems along North America's West Coast, the Cascadia subduction zone and the San Andreas fault, may be more closely connected than previously believed.

From Science Daily • May 2, 2026

While collecting sediment cores from the Cascadia subduction zone off Oregon and northern California, the team accidentally drifted off course.

From Science Daily • May 2, 2026

The study shows that subduction zones do not fail all at once.

From Science Daily • Apr. 29, 2026

However, seismic instruments have occasionally detected earthquake origins beneath continents and away from subduction zones, in some cases as much as 50 miles below the Moho.

From Science Daily • Feb. 20, 2026

The tectonic plates surrounding the Pacific Ocean are converging, or moving toward each other, resulting in a rough arc of subduction faults around the edge of the ocean.

From "Meltdown" by Deirdre Langeland