7 comments on “The Michoacán – Guanajuato Volcanic Field, Mexico

  1. For the Icelandically inclined, a visualization of the recent swarm in Tjörnes Fracture Zone

    Data from NOAA (topography) and IMO (earthquakes)
    Color : Blue for oldest Red for Youngest


    • I’ve been hoping you’d come up with this, thanks, dfm! Amazing how it rises in 3-4 distinct batches side by side and one after another. I wonder if this is now one broad dike or three separate ones.


      • Hi Granyia

        Iceland quakes are always a pleasure to look at because there are this sort of “upwelling”.
        I do not know enough the geology of this part of Iceland to emit suggestions. It is true that there are very distinct events with separate “sheets” . They are distinct in time so it would seem that the magma is trying to find a way up.


  2. Thank you, agimarc! I still don’t get why there are clusters of monogenetic cones rather than central volcanoes. I mean, the magma source below does not disappear after an eruption. Yet, the next batch creates a new path and erupts a few kilometers further away, even within a relatively short time. In other places of the world magmas would go a long distance sub-surface in order to reach a pre-existing outlet – like Katmai>Novarupta.

    Is this perhaps because this area is highly cracked and broken by the very complex tectonic movements? So each (even small) batch of magma would find an almost direct way up and out without having the time to create a permanent plumbing system? (But then, the Katmai region has complex tectonics as well.)


    • Howdy Granyia –

      I think it has a lot to do with how cracked and broken the various blocks are and how they are jostling against one another. Large stratovolcanoes appear at intersections of fault lines – Colima and Popocatepetl for example. Looked like an initial slug of magma at El Jorrulo rose and then stalled until remobilized by the slug of magma that finally made it to the surface. I still don’t understand completely how or why monogenetic fields work, which is one of the reasons I keep on looking at them, There are similarities with NM, Arizona, Utah, Mexico, and Nevada though I have not figured out a way to describe those similarities yet. Cheers –


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