15 comments on “The Utah – Nevada Ignimbrite Flareup of 30 Ma

  1. What a volcanic mess – I would love to see a fast timelapse of all those ignimbrites being laid down and calderas collapsing! So that has been subduction zone (and the continent has moved some 600km west since the time, which is somehow hard to comprehend), there is no chance that volcanic activity could resume anytime in the future. Thanks, agimarc, good find, and a great post!


    • Howdy Granyia – In a past life, I spent a lot of time flying over that part of the US. Would be interesting to look at it again with my current set of eyes (and knowledge).

      I think the slab rollback part of the festivities has pretty well stopped. Current activity in that part of the US is located mostly in NM along the Jemez Lineament and the Rio Grande Rift. It is mostly basaltic in nature. There are some recent basaltic features in Nevada and an earthquake swarm in far NW Nevada that some are watching. I am wondering if the next bit of activity we see in that part of the world will be due to thinning of the NA Plate in the basin and range province. So far it has reduced plate thickness from around 70 km in that part of the continent to near 20 km in a location or two over the last 30 Ma or so. I figure you don’t make that sort of change without creating openings for intra-plate basalts to rise to the surface.

      Final thought: All this happened in the SW US. I haven’t even looked at California yet. Cheers –


  2. The new report from IGP on volcan Ticsani states continuous low activity, but an EQ swarm of 104 events (VT-distal) created a new seismic spot NW of the volcano: “The spatial distribution of seismic activity now shows three groups of earthquakes: the 1st, concentrated near the volcano Ticsani (G1): mainly located about 5 km deep below crater. The 2nd is at a distance of 9 km SE of Ticsani volcano (G2) ~10 km deep. Finally, a 3rd, and new, seismic grouping is located 10 km NW of Ticsani (G3), slightly deeper than previous groups (12 km). See Figure 2.” (The differences in depths of the quakes reported [5km, 10km and 12km resp.] to those shown in Figure 2 [~0 to 7-7.5km] are probably due to the difference of measurement “below surface” versus “below sea level”) This alignment corresponds nicely to the supposed deep fault recently found in the area, activity progressing NW. Perhaps that will be the next eruption site for Ticsani?

    Click to access reporte_ticsani_201614.pdf


  3. Bulusan struck again a few hours ago. Seems to be a bit more serious this time as the PHIVOLCS site is still completely down at the moment.


  4. I wonder if Sabancaya has done another step toward eruption… those stretches of tremor (if that’s what it is) appeared for the first time last night – or at least recently, if I had missed them earlier. It has been very restless lately anyway, with many over M 3 or M 4 earthquakes and countless microquakes. Sabancaya is keeping me in suspense ever since I wrote the post about it!

    source: http://ovi.ingemmet.gob.pe/sismologia/helli_sab07.png

    Webcams here, just in case: http://volcams.malinpebbles.com/pubweb/Peru.htm


  5. New paper out, interesting and right on topic:
    – Surface uplift in the Central Andes driven by growth of the Altiplano Puna Magma Body –
    ‘The Altiplano-Puna Magma Body (APMB) in the Central Andes is the largest imaged magma reservoir on Earth, and is located within the second highest orogenic plateau on Earth, the Altiplano-Puna. … Isostatic modelling of the magmatic contribution to dome growth yields melt volumes comparable to those estimated from tomography, and suggests that the APMB growth rate exceeds the peak Cretaceous magmatic flare-up in the Sierran batholith….’ http://www.nature.com/articles/ncomms13185
    From a “MailOnline” article about it: “These big magmatic systems form during periods called magmatic flare-ups when lots of melt gets injected into Earth’s crust. ‘This is giving us a glimpse into the factory where continents get made,’ Perkins said. ‘It’s analogous to the process that created the Sierra Nevada 90 million years ago, but we’re seeing it now in real time’ “.


  6. Another ancient supervolcanoes are the Lake District in district Cumbria in Northwest England, Snowdonia in Wales and Glencoe in Scotland. The Phlegraean Fields caldera in Italy is also regarded as a supervolcano, albeit a small one.


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