Horst and Graben fault lines geology

Horst and Graben faults in Iran

faults horst grabenA spectacular V shaped fault at Zanjan on the road between Tabriz and Tehran in Iran.

This is a superb example of how geology fault lines can create what are considered horst and graben areas on a very small scale.
fault horsts grabens
Horsts are the higher, uplifted or not sunk areas. Grabens are the lower or not raised up areas.

Horst and graben systems are usually considered to be the geological explanation for ridge and valley areas or mountain and valley systems.

Horst and Graben fault, Iran

Horsts and grabens system

Malta geology: horst and graben features

A geology example of horst and graben faults creating valley and ridges in a fairly flat landscape can be found on the island of Malta in the Maltese islands.
malta geology horst graben geological fault lines gozo comino
What initially created the fault lines?

Could some other force or process have created the fault lines, the high and low blocks of land (the horsts and grabens)? Especially on the limestone islands of Malta and Gozo?