[HN Gopher] The Tectonics Behind the Myanmar Quake
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       The Tectonics Behind the Myanmar Quake
        
       Author : rbanffy
       Score  : 40 points
       Date   : 2025-03-31 11:40 UTC (2 days ago)
        
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       | RcouF1uZ4gsC wrote:
       | > The belt's tectonic activity has birthed many of the world's
       | most impressive mountain ranges, including the Alps, the Atlas
       | Mountains, and the Himalayas.
       | 
       | I though the Himalayas were formed from the Indian subcontinent
       | slamming into the Eurasian land mass?
        
         | knd775 wrote:
         | You don't consider that "tectonic activity"?
        
         | adrian_b wrote:
         | Simultaneously with India, also Africa and Arabia have collided
         | with Eurasia.
         | 
         | So the Himalayas have formed at the same time with a great
         | number of mountain ranges, from the Atlas and the Pyrenees at
         | the Western extremity, passing through many other mountains,
         | e.g. the Alps, the Carpathians, the Caucasus, the Hindu Kush,
         | the Pamir etc., until the Himalayas at the Eastern extremity.
         | 
         | See:
         | 
         | https://en.wikipedia.org/wiki/Alpine_orogeny
        
         | jofer wrote:
         | It might help to think of it less as "Indian subcontinent
         | slamming in" and more as the "Tethys ocean basin closing".
         | 
         | India being pulled away from Africa/Madagascar and eventually
         | beneath the Eurasian continental crust is all related to the
         | closing of the Tethys. ...This is a lot easier to explain with
         | pictures...
         | 
         | If it helps, remember that continents are just lighter and
         | thicker "rafts" of stuff. They're not plates themselves.
         | They're often attached to oceanic crust as part of a plate.
         | When one side of that oceanic crust becomes cold and thick
         | enough to start to subduct, the entire plate gets pulled along.
        
       | aaron695 wrote:
       | Here's a (2014) article talking about it -
       | https://doi.org/10.1002/2013JB010762
       | 
       | "One notably (and perhaps ominously) quiet section of the fault
       | is the 220 km long Meiktila segment, between the large city of
       | Mandalay and the new capital of Naw Pyi Daw. This long quiet
       | section separates a southern cluster of ruptures in 1929 and 1930
       | from a northern cluster between 1931 and 2012. The length of the
       | Meiktila segment implies that it is capable of producing an
       | earthquake as large as Mw 7.8 to 7.9, if it ruptures all at once
       | [Wells and Coppersmith, 1994; Blaser et al., 2010] (Figure 22 and
       | Table 4).
       | 
       | We speculate, on the basis of sparse historical records of
       | shaking, that the 1839 Ava earthquake may have resulted from the
       | failure of Meiktila segment, in conjunction with the Sagaing
       | segment, its neighbor on the north. If the Meiktila segment has
       | been dormant since then, and the fault is fully coupled down to a
       | depth between 12 and 15 km, as Vigny et al. [2003] and Socquet et
       | al. [2006] suggest, then accumulated slip potency on the Meiktila
       | segment after 1839 is enough to generate a Mw 7.6 earthquake."
        
       | sleepytimetea wrote:
       | I liked the photo that one of the quoted seismologists, Zhigang
       | Peng from Atlanta, supplied to the author of this article - which
       | depicts the seismologist standing in front of a sign marking the
       | San Andreas fault on a visit to California. Its just the kind of
       | photo a visiting seismotourist would take !
        
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       (page generated 2025-04-02 23:02 UTC)