108 comments on “Calbuco, Chile – Twin Eruptions on 22/23 April 2015

  1. Look at these earthquakes and how deep they are is this normal and could it be related to all the new activity?

    Magnitude M 4.4
    Region CELEBES SEA
    Date time 2015-04-27 17:34:50.8 UTC
    Location 2.06 N ; 124.76 E
    Depth 248 km
    Distances 562 km S of Davao, Philippines / pop: 1,212,504 / local time: 01:34:50.8 2015-04-28
    64 km N of Manado, Indonesia / pop: 451,893 / local time: 01:34:50.8 2015-04-28
    Magnitude M 4.3

    Region CELEBES SEA
    Date time 2015-04-27 15:48:28.8 UTC
    Location 3.68 N ; 123.22 E
    Depth 506 km
    Distances 409 km S of Malingao, Philippines / pop: 1,121,974 / local time: 23:48:28.8 2015-04-27
    302 km NW of Manado, Indonesia / pop: 451,893 / local time: 23:48:28.8 2015-04-27
    297 km SW of Mabay, Philippines / pop: 3,212 / local time: 23:48:28.8 2015-04-27



        • It is highly unlikely that this quake is related to any other earthquakes around the planet. A big quake can increase the stress on nearby faults, thereby triggering other quakes. However, once you go past a couple hundred kilometers, the change in the stress on the earth’s crust is virtually nil. Likewise, big quakes have little, if any, affect on volcanoes. While there appears to be a slight uptick in eruptions in an area in the years following a major quake, the increase is barely statistically significant. Further study may prove this “increase” to be false. In any case, the increase would be hard to recognize except with statistical analysis, and it would have no affect on volcanoes more than a few hundred kilometers away.


    • Hi Janet, don’t worry about any earthquakes below M6 and deeper than 50 km. They are happening all the time, all around the the world, i.e. all around the plates and sometimes even in the middle of continents. They are all tectonic, the surface of our planet does not pause moving for one minute. There is no new activity, it has been going on like this for millions of years.

      The only thing that really IS new, is the speed and availability of information. 50 years ago, you would not have heard of a single earthquake below M5. Nowadays, if someone feels a shaking, he can just grab his mobile phone and tell someone on the other half of the planet about it. If it was an earthquake which has done some damage, you can even find photos of that on the internet a few minutes later (and a few hours later in a newspaper). You get info services with long lists of every earthquake, and there are A LOT (and always have been). Today we have access to all that. In old times we would only have heard about quakes as powerful as that last one in Nepal. That is the reason many people believe there are more earthquakes now than formerly. The same goes for volcanoes and murders, or anything in the news.

      As for the depth: if one plate subducts under the other, it goes down in a relatively steep angle, and all the way down earthquakes can occur. That means that in a subduction zone you can have earthquakes as deep as ~600km. That’s normal, yes. See this for subduction: http://earthguide.ucsd.edu/eoc/teachers/t_tectonics/p_subduction.html


      • I thought if they said 3m “in the morning”, that could have been some three hours before that image. On the webcams we might not see the overflown lava as it cools to dark color very quickly, but I thought it looked sort of smooth on the rim. It must be wobbling too, perhaps there was just the occasional spill over.


    • I wonder if the name Nemesio is quite common over there, otherwise he would always have his ears ringing or his nose itching (depending on the applying local superstitions) when we mention the name! 😀


        • Hi

          this is the animation of the earthquakes under El Hierro island from January to April 2015.
          The activity is very low but there is a small swarm west of Orchilla at sea at the end of April. These last events do no seem to be related to the recent event under the body of the island.
          The video shows event by event with magnitude, date and hour in the title bar. First view is from the east, then from the south, and finally from the top. the last views show all the event with a rotating perspective.
          Dot color is related to date (see left scale on colorbar). Terrain elevation is shown according to right side of colorbar.
          Data from IGN and NOAA, made for Volcanohotspot on Gnu Octave (Linux version)


          • Thank you dfm! If I remember right those little quakes west of Orchilla have always been there since the last eruption, more or less frequently. Can this not be called sort of background noise or aftermath? Should one not be more worried about that dike going from Tanganasoga to Restinga earlier this year? It is only 10km deep and has red (recent) quakes as well?


            • I do not think it is an aftermath as the depth is under the Moho. time will tell, but things are getting livelier with some other (small) events near and under Tenerife….There is a meeting of the powers that be in Tenerife this week to discuss the quakes under the island.


  2. I hadn’t checked the available cams on the HVO site for a good while, just discovered this one today: Live Panorama of Halemaʻumaʻu Overlook Vent from Halemaʻumaʻu Overlook [HWcam]

    http://hvo.wr.usgs.gov/cams/panorama.php?cam=HWcam OR

    It now clearly looks (to me) as if the rim of the vent is crumbling and falling down into the the lava lake and there are a few cubic meters missing on the left already


  3. Is Calbuco still unstable? I understand that it rained recently. That won’t help the people’s situation over there.


    • Yes, very much so, with higher tremor and nocturnal glow before dawn and continuous ash emission all day, albeit with a weaker plume (<1.5 km high). SERNAGEMIN/OVDAS warn very seriously about the danger of lahars. People should avoid all rivers and channels, especially the 200 meters of either side of them!


  4. There has been a felt earthquake Los Angeles area upgraded to a 4.2.

    SCSN Caltech/USGS Preliminary Report Mw4.2 near Castaic Lake
    Updated magnitude is Mw4.2 & location is 14 km N of Castaic or 14 miles NNW of Saugus, CA. This event is located halfway between the San Andreas fault and the less active San Gabriel fault.
    The epicenter is near Clearwater Fault which is located adjacent to the communities of Lake Hughes and Leona Valley. The thrust faulting focal mechanism with a northeast strike is consistent with the motion on this fault.



    • Please delete the above post as I have posted incorrect information (without checking with my glasses on).
      The correct information is below.

      Magnitude ML 3.6
      Date time 2015-04-30 14:01:16.1 UTC
      Location 33.85 N ; 118.25 W
      Depth 12 km

      The intensity was a IV.



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