( Blog for website at http://users.indigo.net.au/don/ )
Posting this one because after Van (previous post) I came across this rather nice image of the earthquake at Dinar, Turkey (October 1st, 1995), which combined with the erosional features of the landscape helps to emphasise the point that there are different ways in which gravity draws the land down to flatness. Erosion is drawing the loose detritus of the land down and building up the flatness of stratigraphic sequence, .. and the land itself is collapsing.
Fig.1 Dinar Earthquake, October 1st, 1995. The moire pattern when the waveform from the shake is represented getting out of step with itself just a little, makes the effect of the quake easier to see. Down on the left, up on the right. Black-and-white dotted line is the extent of the fault. Dinar itself is just left of the word 'uplift'. (Image courtesy of the authors of this publication on landslide and subsidence monitoring).
Fig.2. Google-location for comparison with Fig.1. Yellow line marks the trace of the fault. Right-click for a bigger image. Vertical exaggeration x2.
The point : All you can tell from the earthquake is that the relative movement across the fault is down to the left / up to the right, .. And if anything is so unlucky as to be shaken by it, it falls down. With enough shaking, it will all fall down; it will be shaken flat. And if that flat is not flat enough, rain and weather will do the rest. End of story - Flat. With time, everything is reduced to flatness. Anything that is hubristic enough to think it can stand up to the force of gravity - or even worse, tries to build itself in the face of it, gets its cumuppance eventually, .. or rather its cumdownance.
Right from the start, the land suffers by erosion. As soon as any bit of it gets a little too high for its boots, it gets rubbed down, ..as the mountains in the picture will show. They're all being eroded. None of them were "pushed up" as Plate Tectonics says, by 'Plate collision'. If any 'pushing-up' occurred at all (which it didn't) then it was an old, near-flat land surface that was already degraded (by 'falling down') - by the inexorable downward force of gravity.
In the face of this inexorable downward force of gravity it makes far more sense to say that both parts of the land surface are falling down, just that one is falling down faster than the other, than it is to say that one is being pushed up. So no pushing up, .. just two 'falling-downs', on which is superimposed the falling down of a third element, namely the rest-level of the agents of erosion represented by lake- and sea-level. As this surface moves down, so does the eroding skin of the land. And under the surface, the falling water table contributes its effect too.
The mountains are an old eroding land surface that is being degraded by erosion, and by subsidence (crustal collapse) along the faults that dissect Turkey. From a wider perspective the erosional surfaces of the world tell us that this 'dropping' down has been a globally continuous event. Water level drops because the floor it's sitting on drops. Not all at the same time of course (as illustrated in microcosm in the above figure), but having dropped, erosion begins over again, reincising the old land surface on the remaining ('upward') side of the fault and laying more sediment down on top of what was there before on the downward side of the fault. On a global scale, the stratigraphic sequence is created - finally to be preserved on the continental crust in the biggest crustal down-dropping of all, ..that happened when the continents separated to expose the mantle, and the surface waters withdrew from the continents towards the ocean basins leaving their stratigraphic residue of millenia behind.
And just to repeat the point : - It's not the 'upward' side of the fault that moves up (generally speaking), it's the downward side of the fault that really does move down, leaving the other side 'high'. Uplift and erosion? Well, .. erosion for sure, day-to-day, as we speak, .. as we watch, .. it's the uplift is the iffy bit. Gets tricky once you start thinking about it, when the base equilibrium level of the eroding element is the immediate (and real) controlling agent of surficial equilibrium, overriden (but only from time-to-time), by crustal movements.
Funny, when you think about it, .. that Plate Tectonics has no explanation for the preservation of stratigraphic sequence on the continental crust ( = the withdrawal of shallow seas from the continental crust). It sees the stuttering build-up of stratigraphy on the continental crust as due to the ebb and flow of waters that somehow had something to do with "the movement of plates", "crumpling the crust" and "building mountains" which got eroded and dumped their detritus over older detritus, in the same way as the eroding mountains of today are dumping their detritus as the alluvial fan between the two lakes in the picture (Fig.1).
But the mountains are not getting 'built'. They are developing from a once (near-) flat surface that doesn't crumple and crinkle over geological time, but gets eroded immediately there is *any* gravitational instability. The crumpling and crinkling that happens deeper in the crust that eventually is exhumed by erosion, is not acting against gravity (to build mountains), it is the depth-expression of the same gravitational force that at surface is causing everything to fall down. The Earthquake at Dinar, Van, Bingol, and everywhere else in Turkey, .. and everywhere else in the world (including what's happening at the oceanic spreading ridges), is the expression of falling down in the inexorable drive towards flatness imposed by gravitational equilibrium, not the expression of sideways-driving convectional force pushing things up. Sideways-movement is the department that other cosmic denizen - the force responsible for changing the first-order shape of the Earth, namely the planet's spin, which is reflected in the symmetry of dynamical change of global geological structure.
Fig.3 Sideways-moving tectonic flow. A combination of collapse of high ground from the north, and westwards crustal lag as the Earth rotates west to east. Big-arrow 'plate' movement is a furphy. The Mediterranean is a dilation tract of mantle extrusion, and the Arabian / North African 'Plates' are linked sedimentary basins, exhumed by the fall in sea-level as the mantle broke through the crust. As all earthquakes show, movement is from the north, .. not the south (Image courtesy same as Fig.1.)
"Surface cracks of the October 1 earthquake have been observed 10 km continuously along the Dinar-Çivril fault. The cracks have displayed a mode of dip-slip; however, some have also indicated lateral slip. The different modes of slip are generally in agreement with the fault plane solution and are indicators of the complex nature of the rupture process."
http://adsabs.harvard.edu/abs/1998PApGe.152...91.
It's illogical to think that colliding plates buckling the crust cause folding and build mountains, when clearly nothing's getting buckled, but on the contrary the land surface is being so rapidly eroded. And if we say that the crumpling is going on at depth then that's hardly "mountains building", is it, ..when not only is it happening at depth, but the mountains we see at surface all around the world in these "collision zones" are manifestly the result of highly aggressive erosion of once-flat, or near-flat surfaces.
Which is not to say that you don't get crumpling by compression ("collision"), .. just that it doesn't build mountains. Blocks of crust that are gravitationally unstable are bound to compress, .. and fold, and slide over each other. They just don't need the help of convecting mantle cells to do it, which have lost all of their energy anyway by the time they get to "collision zones", ..which is why they need to return to the mantle as "subducting slabs". They're cold (in the language of Plate Tectonics), .. no energy left ( in the language of any tectonics). Grandfathered, .. back into the mantle, the draw-cord of the body-bag,.. dust to dust, in the common or garden language we can all understand. But Plate Tectonics would have us believe that in this defunct condition they are about to enter the next life and live the heyday they never had in their former one, .. by knocking up Mother Earth's crust and giving her bulges like there's no tomorrow, and spreading apart continents. (If that's not chauvanistic conceit, I don't know what is.) Tecto-man lives? Hell, .. in that condition he couldn't even lift the hem of her skirt. Who's kidding? Me, you? Or them, us?
So what is it that is lifting the land up? (I mean, causing it to fall down.) Whatever it is, it is related to the extrusion of the mantle and the consequent enlargement of the Earth's surface area. The only logical explanation is that as the Earth's surface area increases to accommodate the massive extrusion of the mantle, everything on it adjusts to take up the newly created areal extent. And does so by subsidence ( 'falling down' ). This is a global phenomenon, commensurate with mantle extrusion, .. It is not a piecemeal result of "colliding plates", sailing about on convection cells, .. crumpling crust.
And it is the sixty-four-thousand dollar question that geologists the world over are doing their level best to avoid. And geophysicists are doing their level best to deny - not that there is an answer, but that there is a question to be addressed in the first place. It's a shameful situation. The pointers to addressing the question are (and have always been) so obvious. We can only hope that the younger cohorts of earth scientists get the message (about the question), because there is no hope that the older ones will, nor will those who have been overfed the diet of Plate Tectonic pap, which they keep gurging and regurging down their mindless, overfed bibs.
And that is the legacy of Plate Tectonics already - half a century of down-the-wrong-road, and another half to pull out of it. Maybe more, when there is no incentive to corrupt careers by doing so, and you can always scrape the half-digested gruel off the bibs and eat that too (rather than wash the bloody thing and try something else).
"A century of misadventure in the Earth Sciences", .. the title of the book that will be written once the change is made, and that can only be written after the fact. You might not know it, but you're living it now in the hundred decibels of silence that refuses to address the question : what is it that makes earthquakes happen and the land everywhere fall down when they do.. And get flat.
Simple question (staring us in the face).
Difficult answer (once you think about it).
But then, thinking is not required inside Big Brother's box (you get voted out if you transgress the rules.) Everybody loves Big Brother, eh? (There's a prize even.)
"Scientists believe" googles 2,410,000
"Scientists think" ... googles 913,000
(with quotations)
Fig.4. Land getting flat. Elevation x3 to emphasise how 'flat' does it : by erosion at surface and crustal collapse at depth (Fig.1). The town of Aydogmus, about 15km SE of Dinar. Mountains by erosion (not by crustal crumpling by colliding plates); rejuvenation as the land and water this side of the fault collapses and the hindward side adjusts by reincision to make hill slopes steeper than they once were; newer re-incision to the left, older (more mature /deeper) reincision to the right. (There might be a fault down that gully between the high bround on the left and the lower ground on the right - or it might just be different lithology.) Smoother slopes sculpted to hold water to prevent erosion.
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