Plate Tectonics
Plate Tectonics

Start this free course now. Just create an account and sign in. Enrol and complete the course for a free statement of participation or digital badge if available.

Free course

Plate Tectonics

3.4 Destructive plate boundaries

Destructive plate boundaries are regions where two lithospheric plates converge. This situation provides a more varied range of tectonic settings than do constructive plate boundaries. Firstly, and in contrast to constructive plate boundaries, destructive plate boundaries are asymmetrical with regard to plate speeds, age and large-scale structures. Secondly, whereas true constructive boundaries occur almost invariably in oceanic lithosphere, destructive boundaries also affect continental lithosphere - they can occur entirely within continental lithosphere. Consequently, there are three possible types of destructive plate boundary:

  • those involving the convergence of two oceanic plates (ocean-ocean subduction)

  • those where an oceanic plate converges with a continental plate (ocean-continent subduction)

  • collisions between two continental plates (continent-continent destructive boundaries).

These can be thought of as representing three stages in the evolution of destructive boundaries.

In addition to the disappearance of old lithosphere, destructive boundaries associated with ocean-ocean subduction and ocean-continent subduction are also characterised by:

  • ocean trenches, generally 5-8 km deep, but sometimes up to 11 km deep. The sea floor slopes into the trenches from both the landward and oceanward sides. They are continuous for many hundreds of kilometres, occurring both adjacent to continents and wholly within oceans;

  • a belt of earthquakes that are shallow-centred closest to the trench and deeper further away. Earthquakes can occur as deep as 600-700 km;

  • most destructive boundaries are associated with a belt of active volcanoes that, in the case of intra-oceanic boundaries, form chains of islands known as island arcs.

Skip Your course resources
S279_1

Take your learning further

Making the decision to study can be a big step, which is why you'll want a trusted University. The Open University has 50 years’ experience delivering flexible learning and 170,000 students are studying with us right now. Take a look at all Open University courses.

If you are new to University-level study, we offer two introductory routes to our qualifications. You could either choose to start with an Access module, or a module which allows you to count your previous learning towards an Open University qualification. Read our guide on Where to take your learning next for more information.

Not ready for formal University study? Then browse over 1000 free courses on OpenLearn and sign up to our newsletter to hear about new free courses as they are released.

Every year, thousands of students decide to study with The Open University. With over 120 qualifications, we’ve got the right course for you.

Request an Open University prospectus371