Why are certain Chinese surnames common in certain provinces? I am referring to the figure below, obtained from Wikipedia


I am aware that about 40% of all Chinese can be characterised into 10 or so surnames. However, breaking it down, there are particular surnames that are common in certain provinces.

I was wondering if anyone knows the history behind this geographic distribution?

I know that certain surnames, such as 陳 were named after their vassal states of China (pre warring state). But obviously, the geography has changed significantly since then.

Are there any other reasons for the high concentration below?
When the Chinese children grow up, usually they don't leave their hometown. And there is an old saying "父母在，不远游". It's just our culture.