Special report: The Italy major earthquake swarm

This is a special report on the earthquake swarm in Italy. Due this being a different country I only have limited information about what is going on in Italy and I don’t have complete knowledge of the area in question. News sources with detailed images of the affected earthquake area can be found here (English) and here (Italian). Those news articles also contains images of the affected areas and aftershock areas (I can only use the image from USGS on the English website).

The earthquake swarm in Central Italy

On 26-October-2016 an earthquake swarm started in Italy, it started with a magnitude 5,5 earthquake (EMSC Information). It was followed by a magnitude 6,1 earthquake (EMSC Information). The magnitude 5,5 earthquake is a foreshock (Wikipedia information) to the magnitude 6,1 earthquake and that is the main event in that earthquake swarm. The magnitude 6,5 earthquake (EMSC Information) today (30-October-2016) is a new earthquake swarm in the same area. It has been followed by a heavy aftershock activity, with more than 300 earthquakes/h taking place in the main earthquake area. It is my view, based on the aftershock pattern that one or more magnitude 6,0 or stronger earthquakes are going to happen in this area in the next few days to months (it’s impossible to know when they happen). It does not help that this area of Italy is crossed with fault lines and they are all active (in the sense they can and do make earthquakes every few decades to hundreds of years).

161026-191800-bovz-psn
The magnitude 6,1 earthquake in Central Italy on 26-October-2016. This image is under Creative Commons Licence, please see CC Licence website for details.

161030-064000-bovzne-psn
The magnitude 6,5 earthquake in Italy on all axes (Z, N-S, E-W). According to the measurement that I saw on my geophone in Denmark, the movement was N-S rather than E-W. There appears to have been some vertical displacement in this earthquake. This image is under Creative Commons Licence, please see CC Licence website for details.

161030-064000-bovz-psn
High resolution of the vertical component (Z) in my geophone. It clearly shows how the earthquake happened in central Italy. This image is under Creative Commons Licence, please see CC Licence website for details.

It is unclear how this is going to progress over the next few days, weeks and months. I don’t know enough about this area to make any type of guess. The area in question is a subduction zone (just not under a ocean) and that makes predicting this activity even more complicated and difficult.

image-20160824-30259-fv2q41
Basic tectonic layout of Italy with earthquake activity on top. Image is from USGS.

There is also a factor that I don’t know about. How often does this happens over the century in Italy. There is only a small clue (and it’s not even clear) of the earthquake list for Italy on Wikipedia (best that I was able to find). In Iceland (for comparison), the SISZ has an earthquake swarm activity (major) every 13 – 90 years (I wrote a list about known earthquakes here). I don’t know how often this happens in Italy, but I suspect that it is at least every few hundred years. How often this happens is mostly controlled by how fast the faults move each year and I don’t have that information.

If anything more happens in Italy I’m going to update this article.

Update on 01-November-2016 at 23:50 UTC

This morning (1-November-2016) a magnitude 4,9 earthquake (EMSC Information) took place in Central Italy. Aftershock activity continues to be heavy in Central Italy. While this earthquake doesn’t look big, it is enough to create more damage into the effected areas. Aftershock activity continues to be heavy in Central Italy.

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Article updated at 23:19 UTC. Word fixes.

Article updated on 1-November-2016 at 23:52 UTC.

This entry was posted in Earthquakes, Italy, Swarm. Bookmark the permalink.

34 Responses to Special report: The Italy major earthquake swarm

  1. Solli says:

    I just wanted to inform you Jón that the conducticity is up to 170 in Múlakvísl and rising. Really a interesting number in this time of year.

    • Thanks for the information. This is unusually high conductivity number for this time of the year in Múlakvísl, its far from normal. Something might start to happen soon.

    • SR says:

      I’ve kept an eye on Múlakvísl for a few days, and if my memory serves me right, the conductivity jumped about two days ago and has remained high since. I noticed it because Katla earthquake activity was very low when this started. At the moment conductivity is 188.3 and rising.

  2. Mike Ross says:

    Does anyone know where IMO are keeping their drums at the moment?

    The map system at http://hraun.vedur.is/ja/drumplot/mapDRUM.php is now dead; the drums never appear on the map.

    And the URLs for individual drums I have been using – e.g. http://hraun.vedur.is/ja/drumplot/drumplot/fed.png are now dead too – 404.

    Thanks

  3. Luisport says:

    Sky TG24 @ SkyTG24 5m5 minutes ago
    #UltimOra #TerremotocentroItalia, #Ingv: The ground has sunk up to 70 cm # Canale50 http://sky.tg/diretta

  4. Scots John says:

    I don’t like the look of that little line of eqs passing by Hekla, that beast doesn’t take much tickling….

  5. Luca says:

    http://emidius.mi.ingv.it/CPTI15-DBMI15/query_place/

    Here you have a Db of known historical earthquakes in Italy and you can filter them for magnitude and location. The page is in italian and english (switch language in the upper right corner).

  6. Luisport says:

    Andrea Banchelli @andreabanchelli Oct 30
    @iiuunniioo @LastQuake @umanesimo perhaps something similar in 1703

    The italian scientists just sayed this quake sequence was similar to the big quake sequence of 1703.
    https://en.wikipedia.org/wiki/List_of_earthquakes_in_Italy

  7. Sarah says:

    You might be interested in these two websites: http://178.33.5.16/en , the English site of the Italian “Centro Nazionale Terremoti”, where you can look up Italian earthquakes back to April of 2005. https://ingvterremoti.wordpress.com/ is their blog where they comment on the seismic events, but in Italian. Try Google Translator to get the gist of it.

  8. Solli says:

    Deeper EQ’s than usual at Katla’s caldera. 7km depth the latest one + conductivity in Múlakvísl at 190 now

  9. Z says:

    Looks like a swarm or something might be starting in Katla?
    http://hraun.vedur.is/ja/drumplot/drumplot/aus_highpass_2.0.png

    • Thoratzer says:

      certainly appears that way, PS I noticed there was a 2.2 mag earthquake listed at around midnight local time which doesn’t seem to appear on the drumplot?

    • If something is starting in Katla volcano, it’s doing so slowly. Something is making the Goðabunga area of Katla volcano more active then usual.

  10. Jan B says:

    Regarding the earthquakes in Italy, the Adriatic Sea is on top a micro plate, the Adriatic plate, not the African plate as in this article. I know that a lot of material is showing the Adriatic Sea is on top of the African plate, but…

  11. The faults that broke in the Italy earthquake continue to make around 200 – 400 earthquakes over a hours (200 – 400 earthquakes/h). There is a slight fluctuation happening at the moment. I don’t know why that is.

  12. Jack McIlveen says:

    Any one else having trouble connecting to the Iceland met site??

  13. Jack McIlveen says:

    “Update in progress

    Our webserver is being updated. Service expected to be available in approx 3-5 minutes.

    English part of our website should be available meanwhile

    You will automatically be redirected to IMO’s home page in about 10 seconds. ”

    but it does not redirect ! I was concerned that something big had happened and there was no Iceland left!

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