Great Glen

The Caledonian Canal, which joins the lakes along the Great Glen fault in Scotland. Earth movements hundreds of millions of years ago displaced rocks either side of the fault. Weaknesses were created in the neighbouring rock, and these weaknesses have since been exploited by river and glacier activity. Loch Ness occupies part of this fault, and a river and the canal occupy it between the loch and Inverness.

Valley in Scotland following a coast-to-coast geological fault line, which stretches over 100 km/62 mi southwest from Inverness on the North Sea to Fort William on the Atlantic Ocean. The Caledonian Canal, constructed by connecting Loch Ness and the lochs Oich and Lochy, runs the length of the glen.

The Great Glen is a rift valley formed approximately 400 million years ago by volcanic activity and deepened by glacial activity around 10,000 years ago. Movement along the fault has made the rocks particularly susceptible to erosion, and the line is marked by a number of deep lochs.

Although the Great Glen fault was formed in relatively early geological times, it continues to remain slightly unstable, and the neighbouring region is subject to slight earthquake tremors.