subduction zone. The subduction zone is the place where two lithospheric plates come together, one riding over the other. Most volcanoes on land occur parallel to and inland from the boundary between the two plates.Share this page: 1  Facebook. 2  Twitter. 3  Google. 4  Email. 5  Earthquakes. 6  Latest Earthquakes.he subduction zone is the place where two lithospheric plates come together, one riding over the other. Most volcanoes on land occur parallel to and inland from the boundary between the two plates. Share this page: 1  Facebook. 2  Twitter. 3  Google.