Attempts to document Native American cultures that were devastated by the westward expansion of settlers is called salvage ethnography. This method involves:

Salvage ethnography involved gathering of available material and interviews.

Explanation:

Salvage ethnography focuses on documenting nearly extinct cultures. For this reason, the collection of material must be quick. The term is often used for describing Franz Boas' work, as he visited endangered Native American cultures.

Salvage ethnography is also responsible for preserving cultures' art, such as paintings and music.