Where do tectonic activities, such as earthquakes or volcanic eruptions, tend to occur?

They tend to occur at plate boundaries.

Sequoia national park  /  inyo national forest, california, u.s. mount whitney is the tallest mountain in california, as well as the highest summit in the contiguous united states and thesierra nevada—with an elevation of 14,505 feet (4,421 m).

Answer they are produced by collision of tectonic plates;