They all play with the tension between empty/solid spaces, solid blocks of color, and use of the grid as an alignment aid.
EDIT: Sorry, I didn't realize you were specifically referencing the use of motion and parallax.
"Parallax" is definitely the most popular term for what you're looking for — there are a number of javascript plugins and tutorials easily found via Google to get you started, it's just a matter of the specific CSS properties you update on scroll events — it seems like you're just looking for a relatively subtle translateY. Alternatively, you could look into this neat/hacky CSS-only approach for that specific effect.
They all seem very derivative of De Stijl.
They all play with the tension between empty/solid spaces, solid blocks of color, and use of the grid as an alignment aid.
EDIT: Sorry, I didn't realize you were specifically referencing the use of motion and parallax.
"Parallax" is definitely the most popular term for what you're looking for — there are a number of javascript plugins and tutorials easily found via Google to get you started, it's just a matter of the specific CSS properties you update on scroll events — it seems like you're just looking for a relatively subtle
translateY. Alternatively, you could look into this neat/hacky CSS-only approach for that specific effect.