Thor
Thor's documented history extends approximately 1,200 years, from early Germanic religious practices through Viking expansion and subsequent Christianisation. The character experienced a revival in the 19th century through Wagner and the Romantics, before Marvel's 1962 comic introduction initiated the current era of dominance.
Whether Thor will remain culturally relevant in another millennium depends entirely upon human choice and entertainment industry economics. Gods, historically, have proven rather mortal when worship ceases.
Volcano
Volcanic activity has shaped Earth for approximately four billion years. The oldest known volcanic rocks predate multicellular life by billions of years. Volcanoes created Earth's atmosphere, its oceans, and the landmasses upon which civilisation eventually emerged.
They will continue erupting long after humanity has departed, reshaping continents with complete indifference to whether anyone remains to witness their spectacle. Time scales measured in geological epochs render human mythology momentary.