They aren’t buried? Or do the roots tear the fibre?

A lot of countries still uses poles for cables, and fiber. It's always super weird to see when you're from an area that buries everything except high voltage powerlines.

For areas with frequent earthquakes I think poles are preferred because it's easier to fix broken cables.

From the part of the Europe where I am from power lines are rarely buried, however fiber is universally buried so I haven’t even considered it could not be.

They’re not buried around here for the most part. I think the population density is just too low to justify the cost.