It is the principle fault line in Malta. It bisects Malta from Fomm ir-Rih to Madliena and is visible for 11km. North of the Great Fault, there are minor faults which have resulted in a system of ridges and valleys, known also as horsts and graben.
Horsts have resulted into ridges such as the Wardija Ridge, Bajjada Ridge while grabens resulted into valleys such as Mistra Valley and Pwales Valley.
Below: A Panormaic view of Ta' Santi - which is part of the Great Fault System. Right-click on the Image and Choose Play to view the Panorama.