Few would have known it, but Morvern has been struck by a series of minor earthquakes over the last month, culminating in a “loud rumble” on Saturday afternoon.
Morvern has been the epicentre of 10 tremors since November 21, mostly measuring below 1.0 on the Richter scale which would not even quiver a cup of tea, until a barely perceptable whopper of 2.1 on December 9 at 3.18pm, which again stirred very little. Typically, people report feeling earthquakes larger than about magnitude 3.0.
However, a “loud rumble” was heard on the Isle of Lismore, which sits on the Great Glen Fault up Loch Linnhe and Loch Ness to near Orkney. “They happen all the time here,” said one islander, breezily. “Sometimes the animals get spooked,” noted another.
Villagers in Mallaig and Morar said they also “felt a weak trembling”, as well as experiencing the same noise. The Great Glen Fault extends down to Islay, where a 1.6 struck at 11.27am on December 11, again recorded by little more than a seismograph.
Scotland has mild seismic activity, despite four fault lines spanning hundreds of miles across it: the Moine Thrust, the Great Glen Fault, the Highland Boundary Fault, and the Southern Uplands Fault. A fault is a large fracture in the Earth’s crust between two tectonic plates. The two plates move and rub against each other, shaking the ground.
It is easier to feel a small earthquake in a very remote area, as road traffic noise, subways or the general hubbub of cities cannot be blamed for unusual movement or sound. Earthquakes would be felt more in the Highlands and Islands.
People close to the epicentre of Scottish earthquakes have described them like: a lorry or train rumbling past, a sound like rushing wind, or a deep rumbling underground.
Moidart experienced one of Scotland’s largest recent earthquakes, a magnitude 4.0 on August 4 2017, since a 4.1 quake near Oban on September 19 1986 and, more recently, a magnitude 4.0 shock in Arran on April 4 1999. “Never felt anything like that, like the ground beneath us was exploding,” averred one Moidart resident. “Terrifying!”
Scotland’s largest earthquake was a 5.2 – enough to damage weak structures – near Loch Awe in Argyll on November 28, 1880. It was felt from Perthshire to Ballycastle in Northern Ireland. Lighthouse keepers as far away as Barra and Lewis also reported feeling movement from the quake.