What is the term for a series of peaks under the ocean that is associated with tectonic activity?

The term describing a series of peaks under the ocean associated with tectonic activity is the Mid-Ocean Ridge. Mid-ocean ridges are underwater mountain ranges formed by the movement of tectonic plates. These ridges are sites of significant geological activity, including volcanic eruptions and the creation of new oceanic crust as magma rises from the mantle.

At mid-ocean ridges, tectonic plates diverge or move apart from each other, creating a gap that allows magma to escape from the Earth's interior. As this magma cools, it solidifies and forms new rock, contributing to the ridge's height and complexity. This geological process is a major component of plate tectonics and is responsible for the dynamic nature of the Earth's crust.

Other options such as ocean trenches involve the area where one tectonic plate is being subducted beneath another, often creating a depression rather than a series of peaks. A continental rise generally refers to the slope that connects the continental shelf to the ocean floor, and while seamount chains do represent underwater mountains, they are typically more isolated volcanic structures rather than a continuous range.