tear up
擘 centers on tearing or splitting something apart by hand, with a sense of forceful separation.
擘 combines 辟 (which likely contributes the sound) with 手 (hand), suggesting an action done by hand. The exact historical development of 辟 is uncertain, but the character as a whole is associated with tearing or splitting by hand.
The top part 辟 looks like a complex object being pulled apart, and the bottom 手 is a hand. Imagine using both hands to tear something into pieces.
For ハク, picture tearing up a document with a sharp 'hack' sound: hack -> ハク, as your hand rips the paper apart.
authority; big-shot; star