Here's why:

* It's subducting: The Juan de Fuca Plate is a smaller oceanic plate that is being forced underneath the larger North American Plate. This process is called subduction.

* Volcanoes and Earthquakes: Convergent boundaries are known for their volcanic activity and frequent earthquakes. The Juan de Fuca Plate's subduction is responsible for the Cascade Range volcanoes in the Pacific Northwest and the numerous earthquakes in the region.

While it's a convergent boundary, it's important to remember that the Juan de Fuca Plate is a remnant of a larger plate that has been breaking apart over time. This means it is also an example of a transform boundary, as it slides past the Pacific Plate along the Cascadia Subduction Zone.