31. august 1819 was the day of the biggest earthquake in the North of Europe in historical time. The so-called “Lurøyskjelvet” on the Helgeland coast could be felt throughout the county of Nordland, but also in Trøndelag, Troms and the northern parts of Sweden and Finland.
– the Shock went on for several minutes. People and livestock had trouble keeping themselves upright, ” says Odleiv Olesen at the Norwegian Geological Survey (NGU). He has researched and written a longer article about the incident.
This was an exceptionally large earthquake. Today, it is a powerful reminder that even seemingly stable Norwegian fjellgrunnen is completely safe.
– After 1819-magnitude quake was reported about the big waves and stormy seas, which is probably due to submarine landslide, says researcher Odleiv Olesen at the Norwegian Geological Survey.
Photo: Morten Andersen / NRK
Scientists believe that the earthquake of 200 years ago had its epicenter in Lurøy municipality in the Helgeland in Nordland.
There are several depictions of what happened on the last augustdagen in 1819.
Sokneprest Iver Ancher Heltzen wrote in the book Ranens Description of rock formations as dundret down the mountain.
“Fjeldene rystede saa stærkt that the forvittrede Stenmasse on their Top and on their Sides faldt down with one thousand Brag … the Earth bævede saa stærkt that the People who care ude on the ground, could not stand, then Knæerne ej would carry them….”
the Trader and gjestgiver on Lurøygården, Isaac Jørgen Dass, told of several rock falls in the mountains. He also described that the spring below the mountain was blakket as if it were milk, and that it smelt strongly of sulphur. According to the Dass could not the water is drinkable for several days.
Minor injuries, many aftershocks
In the Nordland, the number of foundations and chimneys damaged or destroyed. As far south as Overhalla in Trøndelag was reported to be a severely damaged chimney. Nevertheless, there were few reported injuries on the buildings.
This happened before industrialisation. Settlement was a large house in the log timber or the frame with one floor and a turf roof, ” says Olesen.
“Lurøyskjelvet” was followed by several weaker aftershocks. They could be marked every hour until seven o’clock the next morning, and then daily for the next four to five weeks. There were also aftershocks in the several years after 1819.
Can a similar earthquake happen again?
the Strength of the “Lurøyskjelvet” is estimated to be about 5.8 on the Richter scale.
the Researchers estimate that quakes with a magnitude of five and six will be performing on the Helgeland coast, with respectively 130 and 1500 years apart.
According to Olesen is skrekkscenarioet that a future earthquake triggers leirskred or landslides. A subsequent flood can have catastrophic consequences on the coast of Helgeland.
In 1819, one got rock falls and leirskred. If a hypothetical earthquake in the future trigger landslides or leirskred on land or under water, it will form large flodbølger, tsunamis. It will be a short time for the notification from the wave being formed and it hits the ports and buildings close vannflata. It is the biggest risk.
Since 1819 has the population in the Rana area also increased from 5000 to 30 000 in 2019. Today, there are high buildings, railways, bridges, kraftverksdammer, tunnels and open-pit mining in the area. The extent of the damage may be a completely different than 200 years ago, ” says Olesen.
today, account is taken of possible earthquakes in the area. It is, among other things, stricter requirements to the dimensioning of the buildings and other constructions on the coast of Nordland.
Olesen believes that the people are not going to worry about.
– There are many other dangers in a modern society that is much bigger than a large earthquake. It is important to be aware that the risk is not equal to zero. Calculations show that at Helgeland can go many hundred years, maybe thousand years between each earthquake.
The marked area shows where the leirskredet after the earthquake in 1819 went. The wife on the farm Storstrand went out and picked potatoes on this field, but saved probably life because she was inside to the food when the slide went. Potetbøtta was owed on the fjord. Raskantene was leveled with a bulldozer in the 1960s, but is still visible today.
Photo: Odleiv Olesen
the Earthquake triggered several rock falls from the Liatinden by Aldrasundet in Lurøy municipality. It led to the former slåttemarka had to be stated.
Photo: Odleiv Olesen
Nordland is often prone to minor earthquakes. The area around and under the 1032 metres high Blokktinden at Helgeland had around 500 earthquakes from april 2015 to march 2016. Researchers at the University of Bergen, norway estimated that they originated at 2-10 km deep. The great steinura on the northwest side of the mountain can partially be formed as a result of prehistoric earthquakes.
Photo: Elisabeth Sjåvik Monsen
Five earthquakes in a row can be notice about the “jordskjelvsverm”
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