Plate tectonics 101—What happens at hot spots?

As seen in my last three posts, most geologic action occurs at the boundaries between lithospheric plates. But in some places we find active volcanoes and earthquakes that are not at plate boundaries. This post will explore these places, where geologic action is occurring at so-called "hot spots". What are these features; what causes them; and what are some of...

Plate tectonics 101—What happens when plates slide past each other?

Oceanic crust is created at divergent plate boundaries and destroyed at convergent boundaries, but transform boundaries cause neither; rather, they transform motion between other types of plate boundaries, enabling plates to move about efficiently on our spherical planet. In this post, we will explore various examples. The majority of transform boundaries are found in the ocean, where they separate segments...

Plate tectonics 101—what happens when plates move toward each other?

When plates move away from each other (divergent boundaries; see last post on December 31), new oceanic crust is created. Since Earth is not expanding, ocean crust must be destroyed elsewhere. This happens at convergent boundaries, where plates move toward each other. Here, oceanic crust is destroyed, or rather, it gets recycled back into Earth's depths. The places where oceanic...

Plate tectonics 101—what happens when plates move away from each other?

It's winter in the midst of a pandemic, and travel is restricted. So it seems a good time to go back to some geologic basics, the knowledge of which are sometimes assumed in these blog posts. The next four posts will explore the essentials of plate tectonics—the underpinning of our modern geologic understanding. Plate tectonics refers to the processes that...

About the Blogger

Karen (here with Mt. Shasta in background) is a geology professor emerita who aims to provide a "pocket geologist" for world travelers. Follow the blog to explore the landscapes of our planet and figure out what causes them to look the way they do.

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