Gwhy are there active volcanoes along the pacific coast of washington and oregon, but not along the east coast of the united states?

Cascade volcanoes

Explanation:

The volcanoes of the mount st Helens and the mount rainier, mount Adams and those of the Oregon ae the mount hood, mount Jefferson and mount baker. These volcanoes form a part of the volcanic arcs of the western port America and are part of the ring of the fore and the Cascade subduction zone and geologically are numerous shields and the stratovolcanoes and the lava domes.

No, because you are more likely to see volcanic mountains where magma is rising along the mid-ocean ridge spreading to the center.