Photo of Westman Islands

The Top 5 Biggest Earthquakes in Iceland

Iceland is located in a tectonically active zone, meaning tremors are part and parcel of everyday life. As is the case across the globe, seismologists constantly measure its earthquake activity using a number of methods. The Mercalli scale, for instance, works on visual evidence and takes the amount and significance of damage caused by seismic processes into consideration.

However, that method is a little hit and miss if you remember that human activity plays an important role. The impact of an earthquake will be affected by factors such as quake-proofing techniques in construction and the level of education and earthquake preparedness in the local population.

The main alternative is something called the Richter Scale, which was invented in the 1930s by a man named Charles Richter. He proposed a logarithmic scale that classified quakes by magnitude, which means for every single point increase on the scale, the earthquake is 10 times greater. This method uses specific scientific measurements rather than observations and has been widely adopted. 

When you read reports about earthquakes, this is the figure to which those articles refer. Though technically there’s no top of the scale, the largest event ever recorded to date is a 9.5 magnitude quake that struck Chile in 1960. 

Other quakes that were almost as large include the 9.2 that hit Alaska in 1964, the 9.1 that triggered the catastrophic tsunami in 2004 and the 9.0 that devastated Japan in 2011. So all of these, as we shall see, are significantly greater than the largest to ever have occurred in Iceland.

Recently, there has been a resurgence of seismic activity on the Reykjanes Peninsula, potentially signaling an imminent eruption in the area.

But just how large are the top five biggest earthquakes in Iceland? Let’s find out.

Lately, seismic activity has resurfaced on the , which could be an indicator to the next Reykjanes eruption.

1784

Lakagigar

The largest earthquake ever to strike Iceland occurred in the South Iceland Seismic Zone (SISZ) around the time of the massive Laki volcanic eruption in 1784. Seismologists estimate that the biggest earthquake in Iceland would have been a 7.1 on the Richter Scale had that system of measurements been invented back then. A slightly smaller 6.9 aftershock struck two days later.

1896

Over a two-week period in 1896, a series of five significant earthquakes hit a relatively small area of South Iceland – located within about 50km of each other. They have since been estimated at 6.9, 6.7, 6.0, 6.5 and 6.0 on the Richter Scale. 

1912

Another earthquake in the same region in 1912 is considered to be a 7.0 on the scale, possibly the second biggest earthquake in Iceland history. Though again, the Richter method was yet to be invented, let alone adopted. It was an example of something called a strike-shift quake, which occurs when pressure builds up on a plate boundary and then releases, forcing the rocks to jolt in a movement that takes place parallel to each other.

2000

Siglufjörður

In the intervening years, the largest quake in Icelandic territory was a 6.9 that happened off the north coast WNW of Siglufjordur in 1963. However because of its maritime location, there were no reports that anyone felt the quake, despite its size. Decades later, in 2000, a quake struck on June 17th, Iceland’s National Day. 

The Icelandic authorities estimated it as a 6.4 on the Richter Scale, though the US Geological Survey recorded it as a 6.6, making it the largest since 1912. As the depth was rather shallow – just 6.3km beneath the surface – it caused some damage. The quake centred on the Westman Islands in southern Iceland, though it was also felt in Reykjavik. Three people suffered minor injuries. A second quake (of a similar magnitude) happened four days later.

2008

More recently, there was a 6.5 quake in 2008 (some reports measure it as a 6.3 on the Richter Scale). Again, this occurred in the SISZ. The epicentre of the quake was very close to the South Iceland town of Hveragerði. If you call in to the town’s visitor centre you can view an interesting display of pictures and information that tells the story of what happened and experience what it might have felt like. 

Experience the Force of an Earthquake in Iceland

If you’re keen to learn more about earthquakes and tectonic activity in general, then you should make a point of visiting Perlan when you are in Reykjavik. The Forces of Nature exhibit explains the processes that shape Iceland’s landscape and will give you a better understanding of what causes our earthquakes, volcanic eruptions and geothermal activity. 

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