Week 3 : Earthquakes

     Norway's mainland is a location that is very fortunate to not have a high concentration of earthquake activity. Active volcanoes and fault lines aren't located close enough, so the dangers of earthquakes are minimal, but not completely absent. A factor that is the cause of the seismicity within and around Norway is a post-glacial rebound.

A post-glacial rebound is the rise of landmasses that have sunken from the enormous weight of ice sheets. When a post-glacial rebound occurs, the Earth's crust sinks into the asthenosphere. This is known as isostatic depression.

These two photos below show the seismic activity and magnitude of Norway. I find it very interesting that the edges of the country have a higher impact rate, but while looking at the photo on the bottom right, we can see that most of the intensive earthquakes take place within the middle of the country.

     In Norway, seismic activity is monitored by the Norwegian Seismic Array NORSAR. They communicate, share information, and spread awareness with other organizations throughout the world. With an account on NORSAR, one can see the consistency with their updated list of seismic occurrences not only with Norway but across all of northern Europe. Below shows the most current information on the seismic activity of today, February 8, 2022.





Works Cited

https://www.cs.mcgill.ca/~rwest/wikispeedia/wpcd/wp/p/Post-glacial_rebound.htm#:~:text=Post%2Dglacial%20rebound%20(sometimes%20called,process%20known%20as%20isostatic%20depression.

https://en.wikipedia.org/wiki/Isostatic_depression

https://www.lifeinnorway.net/earthquakes-in-norway/


https://www.researchgate.net/figure/Postglacial-rebound-rates-relative-to-MSL-in-mm-yr-according-to-Kakkuri-1997-The-map_fig2_281388107


https://www.researchgate.net/publication/200678424_To_what_extent_is_the_present_seismicity_of_Norway_driven_by_post-glacial_rebound 


https://www.semanticscholar.org/paper/To-what-extent-is-the-present-seismicity-of-Norway-Bungum-Olesen/88d2acb1c592161616a3df7fe14b78a40290b373


https://www.volcanodiscovery.com/earthquakes/norway.html 



Comments

  1. Luke MelcherFebruary 9, 2022 at 10:17 AM

    Hey Jonathan!

    I think that living on the west coast blinded me from the fact that there are a lot of places that do not have to worry about earthquakes as much like Norway! My country, Argentina, is similar to California in that it lies on a plate boundary, causing earthquakes frequently throughout the year. That is extremely interesting about Norway's ice sheets and how immense they are to be able to cause a post-glacial rebound. As the oceans warm, I wonder how this will effect that occurrence. I think that it is smart NORSAR includes seismic activity from other countries because earthquakes have the ability to affect people thousands of miles away from the focus.

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  2. Ana GGFebruary 9, 2022 at 10:17 AM

    Very good seismic post! I enjoyed that you connected the isostatic rebound here. I was thinking about how some of the northern countries experience icequakes (link below if anyone wants more)
    Comparing their population density map (https://commons.wikimedia.org/wiki/File:Norway_Population_Density,_2000_(6171915347).jpg) and the riskier areas, it seems the population is feeling some of those quakes, even if they are not major ones, so it is good they have the monitoring system in place.

    https://en.wikipedia.org/wiki/Cryoseism

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  3. AmandaFebruary 13, 2022 at 6:10 PM

    This was so interesting! I have never heard of post-glacial rebound before. I wonder how global warming affects this. If the rebound allows plates to move up, could this cause a larger earthquake?

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