Toba caldera: Ring of Fire - tectonic journeys in E Asia
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- čas přidán 5. 09. 2024
- This is ground zero for the largest volcanic eruption in the past two million years - Toba on the island of Sumatra. What is the structure of the volcanic complex? What can we learn from the landscape and some preliminary geophysical experiments? This is one of a series of films made to accompany the BBC's 4th series of "Race Across the World" - looking a geology of this stunning region.
#geology #Tobacaldera #tobalake #tectonics #ratw #volcano #ringoffire
I've long wondered why Toba -- just a regular old subduction arc volcano -- has such a damn monstrously huge magma chamber.
So glad CZcams recommended your channel! I'm saving this to my "Science, geology" playlist for further study.
Excellent presentation. Thankyou squire.
Thank you for this video, it was very interesting. I particularly like the description of the magma chamber as a complex patchwork.
Thanks - yes - there's lots to be done on understanding the dynamic structure of magma chambers - more insights coming these days from better geophysics ... but also more can come from ancient ones in the geological record....
Since you are talking about SE Asia, the Gulf of Tonkin / Yinggehai Basin / Song Hong Basin has a great deal to offer. A pull-apart basin with exceptionally high sedimentation rates and shale diapirism, on top of that the very real possibility that the 788 ka Australasian Tektite source crater measuring c. 43 km diameter, slumped to 100 km, is present in a chaotic seismic zone in the center of the basin. This basin has a lot to reveal.
Thanks for the info. My series has concluded for now - off to do other things - but the region has a super-rich set of geo-stories... so i'll be back!
Very informative.
I suspect, when India was jammed forward, into southern Asia, carrying southeastern Asia with it, the Indonesian archipelago absorbed an incalculable amount of material in a very short time, causing all, and every, magma pipeline to spew lava like a pop-gun!
Thank you for the videos I'm learning so much from them
I hope one day you could cover the geological history/ mountain formation of Romania?
I’m a new subscriber and wanted to thank you for the way you present your videos. I’m learning so much from you.
Welcome aboard! there are a few up to catch up on... hope you enjoy them!
@@robbutler2095I’m sitting here watching and it makes sense….ok not all of it, but you are an excellent teacher. I’m so glad I found your work.
That much land was liquefactioned!? Wow, good good
see below in the chat. The YTT eruption ejected 2,800 km3 of dense rock equivalent - not the figure I mention here (out by an order of magnitude). Still vast - and the greatest single eruption in the past 2 Myr.
I think one of the more recent estimates is 3,800 km³ DRE -- with a total bulk volume of possibly around 13,200 km³
Frickin monster. About brakes the scale
Does Mount Toba have the potential to become active again?
Yes - absolutely - though not necessarily so catastrophically. There's still an active magma chamber below...
Some Indonesian Scientist argue that the Toba Magma Chamber is now fueling the Sinabung Volcano up north of Lake Toba now
The lake it self really deep. The last check is 1600 m deep. If you try to search, there case where a boat end up drowning and many of bodies of victims who we can't take back to furnace because it's to deep and almost no light. That the most saddest accident in my country indonesia
Re the quoted volume......it is 2,800 km^3 not 28,000 km^3. I have always wished there were more detailed field studies of the caldera filling and outflow ignimbrite sheet such has been done for Aso 4 and Campanian.
Thank you - well-corrected - it's 2.8k km^ 3 - but yes - lots of work to be done here!
It was 13,400km^3 not 2,800
Im surprised you didnt include the extensional component as a major driver for really large volcanic systems in subduction zone settings. The same is true for taupo in NZ .
Interesting - but unlike Taupo and the continuation towards the Wanganui Basin, around Toba and that corner of Sumatra, there are (as far as I know) no normal-fault fault plane solutions from earthquakes. There are some out in the forearc - but not along that segment of the arc. My point would be that the proximity to the GSF could promote transtension (or in relay ramps).... But overall - more data needed!
Re: Eliptical shape of caldera .... Do we have evidence for the movement of the Great Sumatran Fault being consistent along it's entire length for 70 000 years or more? And is the fault a comparatively simple single straight structure passing this location?
Might another reason for the currently evident shape be related to pre-eruption topography? Thinking here of the markedly asymmetric 1980 eruption of Mt.St.Helens.
Thanks for the questions:
The scale of the caldera precludes I think any significant topographic controls... unlike St Helens...
Certainly the fault trace of the GSF is straight(ish) passing Toba - though hard to say long-term given the masking by YTT and other deposits. There may be older relay structures...
Check out last week's film on the GSF...: czcams.com/video/Jskd-YbO6CE/video.html
Apatu?
I wonder if there is any shocked quartz in the area. Could an asteroid impact have triggered the eruption???????? An oblique hit would leave such a scar!!!!! Just wondering!!!!!!
No shocked Qz as far as I know. Although the shape might be consistent with impact origins, the absence of associated deformation features etc would make this explanation very unlikely...
I have read that it does have shock metamorphic features and is used to argue by some that volcanism can produce these features.
No, and it is rare to get an elliptical crater, even impacts down to 5 degrees create near-circular craters.
In E asia? Huh? E?