Three-fourths of Earth's active and dormant volcanoes -- including Mount St. Helens, which is featured in the program &quot;Hell's Crust&quot; -- lie along this arc, at the margins of the Pacific Ocean, where the large Pacific plate and other tectonic plates dive beneath yet other plates.
(Mount St. Helens; is featured; in the program &quot) (Three-fourths of Earth's active and dormant volcanoes -- including Mount St. Helens; lie; along this arc; L:at the margins of the Pacific Ocean) (the large Pacific plate and other tectonic plates; dive; L:beneath yet other plates; L:the Pacific Ocean)
Mount St. Helens Three-fourths of Earth's active and dormant volcanoes -- including Mount St. Helens the large Pacific plate and other tectonic plates
is featured lie dive
in the program &quot
along this arc L:at the margins of the Pacific Ocean
L:beneath yet other plates L:the Pacific Ocean