Crustal Displacement 2012hoax
Crustal Displacement: Science versus Science Fiction
Table of Contents
Planetary Motions: Milankovitch Cycles
No gigantic earthquakes and tsunamis
One of the major classes of 2012 disaster scenarios involve a proposed sudden shift of the earth’s true (rotational) poles, resulting in massive earthquakes, tsunamis and, as depicted in the film 2012, triggering the eruption of supervolcanoes such as the Yellowstone caldera. It cannot be said too often nor too emphatically that a planet’s rotational poles are separate and distinct from its magnetic poles, and while scientists know that the earth’s magnetic poles have definitely flipped over geologic time, there is no evidence that the rotational poles have shifted significantly from their current position. The inclination or tilt of a planet’s rotational poles are measured with respect to the planet’s orbital plane. For example, if a planet’s equator is in the same plane as its orbit, then its poles are said to have zero inclination. Such a planet has no seasons. If a planet’s poles are aligned in the same plane as its orbit, then the planet is said to be “tipped over on its side”, which is the current fate of the planet Uranus. As a result, Uranus’s seasons are extreme, and its North and South Poles are alternately plunged into decades of extreme darkness as the planet orbits the sun.
Planetary Motions: Milankovitch Cycles
Currently the earth’s rotational poles are inclined by 23.4 degrees and historically this angle has only varied between 22 and 24.5 degrees (Burroughs 2003, 209). According to the well-known climate change model of Serbian geophysicist Milutin Milankovitch, the inclination changes in a cyclical way, as do two other fundamental properties of the earth’s motions, namely the shape of the earth’s orbit (or eccentricity) and the orientation of the North Pole with respect to the stars (a roughly 26,000-year circular wobble known as precession). Currently, the earth’s orbit only differs from a perfect circle by 3-4 %, a change too small to significantly impact our seasons. For example, as any Alaskan can attest, the earth is not suddenly warmer on January 4 of each year when it is technically closest to the sun. However, Milankovitch proposed that the combination of these three cycles (each with a different period) leads to variations in climate through changing the latitudinal and seasonal distribution of sunlight.
Precession
The discovery of the first two effects are modern, but precession was known to the ancient Greek astronomer Hipparchus (c. 150 BC), who noted differences in star positions between his star maps and older Egyptian maps. For example, while the star Thuban in Draco was the star closest to the North Celestial Pole in the time of the pyramids, in Hipparchus’s era two stars at the edge of the bowl of the Little Dipper, sometimes referred to as The Guardians of the Pole, served in that role. Today Polaris, the star at the end of the handle of the Little Dipper serves as our North Star, but not permanently. Precession is caused by torques exerted on the spinning earth by the gravitational influence of the sun, moon, and other planets.
The Tectonic Factor
If the actual rotational poles of the earth do not shift by a significant amount, how do scientists explain the existence of evidence of fossil palm trees in ancient rocks in Alaska? The most widely accepted scientific explanation is plate tectonics, an outgrowth of Alfred Wegener’s 1915 model of continental drift. The basic concept is that the exterior of the earth (a thin layer made of rigid rock and termed the lithosphere), is broken into pieces termed plates. For those readers more familiar with the crust-mantle-outer core-inner core onion layer model of the earth’s interior, the lithosphere is composed of the crust and the uppermost mantle. The plates of the lithosphere move over a more flexible, plastic-like mid-level mantle layer called the asthenosphere. This motion is probably driven by the circulation of material deeper in the mantle. The locations where plates come together and interact – termed plate boundaries - are commonly associated with earthquakes (as in Southern California), volcanoes (such as Mt. St. Helens), and mountain building (like the still-growing Himalayas). Through the slow (~ 5-10 cm/year) motion of plates, the current continents have periodically come together to form supercontinents, such as Pangea (c. 300 million years ago) and the lesser-widely known Rodinia (c. 800 million years ago). Due to plate tectonics, Alaska has spent time closer to the equator in the past, and at that time enjoyed a more tropical ecosystem than at present.
Wegener’s original model of continental drift was not universally embraced by the scientific community, not the least reasons being that he did not have a satisfactory mechanism to drive the “drift” and he also had a fundamental error in his theory. It is not the continents that move and change, but the individual pieces of the entire outer layer of the earth, including the ocean floor itself, which is destroyed and created at plate boundaries. It was not until the 1960s, with the advent of detailed studies of the reversal of earth’s magnetic fields as documented in rocks formed in the ocean floor at plate boundaries, that the revised model of plate tectonics was confirmed.
Hapgood's Crust Displacement
An alternative idea to plate tectonics was proposed in 1959 by history professor Charles Hapgood, which he termed crust displacement. In his model, the lithosphere (as a whole, solid piece) occasionally slips over the asthenosphere, like a sock twisted around your foot. In this way, landscapes which are now polar could become tropical, and vice versa, leading to dramatic climate and, as Hapgood stressed, evolutionary changes (Hapgood 2009, 319). Hapgood conceded that he had no driving mechanism for his model, although he thought it was related to “gravitational imbalances within the lithosphere” (Hapgood 1999, 41).
Uncritical acceptance
Not unexpectedly, numerous 2012 authors and media have embraced Hapgood’s crust displacement model (for example, the film 2012) without critical scrutiny. They conveniently ignore the fact that Hapgood’s ideas have been refuted by mainstream geology, and that even a 1959 review noted that the book had “a number of elementary errors” (Longwell 1959, 137). Instead, they use as proof of Hapgood’s ideas the fact that Albert Einstein wrote a foreword to the first edition of Path of the Pole. While Einstein was of course a highly intelligent man, and a noted physicist, he was not a geologist, and could certainly not be considered a peer reviewer in paleoclimatology or plate tectonics.
In a proactive strike, it is worth mentioning that if the 2012 community thinks it can use geological evidence gathered from Titan and Europa as evidence for Hapgood’s theory, they should think twice. Titan and Europa, large moons of Saturn and Jupiter respectively, are indeed capable of undergoing a kind of crust displacement, only because their crusts are decoupled from the oceans underneath. Unless 2012 proponents are taking a page from the hollow earth crowd and claiming that the earth’s surface floats on a subterranean global ocean, Titan and Europa are useless to them. In addition, Titan’s surface is sliding a disappointing 0.36 degrees in latitude per year, and there has been no apparent motion of Europa’s surface (Lorenz et al. 2008, 1649). Certainly this is not up to Hollywood standards.
Other Motions
Is there any support among mainstream geologists for motion of the earth’s surface in addition to plate tectonics? Interestingly, there is. Of minor consequence is the Chandler Wobble, a change in the location of the rotational poles with respect to the continents, with a period of 14 months, a maximum displacement of a few meters, caused by seasonal changes in the mass distributions of the atmosphere and oceans (Maloof et al. 2006, 1100). Geologists have determined that there is also an additional roughly 10 cm per year change in the relative position of the continents to the rotational axis, thought to be caused by the earth’s moment of inertia continuing to adjust to the changes in its mass distribution resulting from the melting of the glaciers of the last ice age (Maloof et al. 2006, 1100). Such changes in the position of the distribution of the continents as a whole relative to the rotational axis is termed true polar wander (TPW), and is carefully distinguished (at least by geologists) from apparent polar wander (APW), which is caused by the motion of individual plates (Steinberger and Torsvik 2008, 620). APW is measured through the magnetic field orientations frozen into rocks containing magnetic minerals, which are aligned to the relative direction of the earth’s dipole field at the times the rocks formed.
True Polar Wander
Evidence exists for larger events of true polar wander, perhaps as much as 55 degrees or more, although the geological community is not unanimous in its interpretation of the data (e.g. Tsai and Stevenson 2007; Li and Zhong 2009; Phillips, Bunge, and Schaber 2009). Even more extreme cases have been proposed, termed inertial interchange true polar wander (IITPW), in which the entire earth’s surface appears to shift by as much as 90 degrees in a geologically short period of time (e.g. Kirschvink, Ripperdan, and Evans 1997). Both TPW and IITPW are presumed to occur from similar causes, namely the earth’s reaction to a redistribution of mass (due to changes in glaciations, the formation of supercontinents, or large-scale movements of magma within the mantle). Because the earth is not a perfect sphere, it has three axes and thus three moments of inertia. Such an object can rotate stably around both the axes of maximum and minimum inertia, but in order to expend the least amount of energy it will always tend to rotate around the axis of maximum inertia. For the earth, this corresponds to having the rotational poles at 90 degrees from the equatorial bulge (as the earth is larger around the equator than it is around a circle of longitude connecting the north and south poles). A spinning object cannot stably rotate around the axis of intermediate inertia. In TPW, a redistribution in mass shifts the location of the axis of maximum inertia, and the entire outer earth shifts (presumably on the boundary between the outer core and the mantle) in order to align the new axis with the rotational axis. In IITPW, the change in the mass distribution shifts in such a way that the axis of maximum inertia changes by 90 degrees, becomes the axis of intermediate inertia, and the earth’s outer layers respond by shifting by 90 degrees in order to re-establish the proper balance (Steinberger and Torsvik 2008, 620; Phillips, Bunge, and Schaber 2009, 2).
Real shifts take time
At first glance, these scenarios may seem to support Hapgood’s crust displacement, and give some credence to certain 2012 catastrophe models. However, a more careful examination of the facts negates these conclusions. Firstly, Hapgood’s model is meant to replace plate tectonics, and the shifting occurs at the lithosphere/asthenosphere model (relatively near the surface of the earth), while TPW and IITPW occur in addition to plate tectonics (and are connected to changes in mass distribution created by it), and the motion occurs far deeper inside the earth, at the core-mantle boundary (CMB). As seen in the film 2012, such shifts are expected by pseudoscience proponents to be almost instantaneous, with a 23 degree pole shift occurring in a few hours. In reality, although the exact timing of such events is currently under debate among geologists, most studies suggest a rate of speed of no more than 1-2.4 degrees per million years (e.g. Tsai and Stevenson 2007, 9; Steinberger and Torsvik 2008, 620). Such a slow change obviously does not make for good cinema (or convincing apocalypse scenarios).
No gigantic earthquakes and tsunamis
In addition, both the film and various 2012 websites suggest that gigantic earthquakes and tsunamis, coupled with significant changes in sea levels, will simultaneously occur with the posited pole shift. In reality, the scenario is quite different. Since the oceans respond faster than the solid mass of the earth (being obviously more fluid), changes in sea levels are seen long before any uplifting of the crust is noted (Maloof et al. 2006, 1100). In addition, while it is true that in Hapgood’s scenario the lithosphere will be stretched and fracture as different parts of it are rotated down over the earth’s equatorial bulge, since the real lithosphere is broken into plates, these suture points allow for the lithosphere to expand or contract by a factor of 0.3% (Tsai and Stevenson 2007, 2). Therefore while it is certainly possible that tectonic activity such as earthquakes can accompany the readjustment of the earth during TPW, there is no reason why it should lead to catastrophic earthquakes such as the 10.9 California quake (and the cartoonish vertical and horizontal motions depicted in the widely viewed limousine escape scene) of 2012. It is possible that the director and writers of the film took their cue not only from Hapgood, but from the well-known pseudoscience works of Immanuel Velikovsky, including Worlds in Collision and Earth in Upheaval, which contain such catastrophic events. There is also no known geological reason why a TPW should be connected with a magnetic pole shift, although the two are commonly connected in 2012 propaganda (including the film 2012).
— KML, 12/20/09
References:
Burroughs, William James. Weather Cycles: Real or Imaginary? 2nd ed. Cambridge: Cambridge University Press, 2003.
Hapgood, Charles H. Path of the Pole, 2nd ed. Kempton, IL: Adventures Unlimited Press, 1999.
Kirschvink, J.L., R.L. Ripperdan, and D.A. Evans. “Evidence For a Large-scale Reorganization of Early Cambrian Continental Masses by Inertial Interchange True Polar Wander.” Science 277 (1997): 541-5.
Li, Zheng-Xiang, and Shijie Zhong. “Supercontinent-Superplume Coupling, True Polar Wander and Plume Mobility: Plate Dominance in the Whole-Mantle Tectonics.” Physics of the Earth and Planetary Interiors 176 (2009): 143-56.
Longwell, Chester R. “Review: Earth’s Shifting Crust, by Charles H. Hapgood.” Geographical Review 49 no. 1 (1959): 135-8.
Lorenz, Ralph D., et al. “Titan’s Rotation Reveals an Internal Ocean and Changing Zonal Winds.” Science 319 (2008): 1649-51.
Maloof, Adam C., et al. “Combined Paleomagnetic, Isotropic, and Stratigraphic Evidence for True Polar Wander from the Neoproterozoic Akademikerbreen Group, Svalbard, Norway.” GSA Bulletin 118 (2006): 1099-124.
Phillips, Benjamin R., Hans-Peter Bunge, and Katrin Schaber. “True Polar Wander in Mantle Convection Models with Multiple, Mobile Continents.” Gondwana Research doi:10.1016/j.gr.2008.11.007, 2009.
Steinberger, Bernhard, and Trond H. Torsvik. “Absolute Plate Motions and True Polar Wander in the Absence of Hotspot Tracks.” Nature 453 (2008): 620-3.
Tsai, Victor C., and David J. Stevenson. “Theoretical Constraints on True Polar Wander.” Journal of Geophysical
Comments
Post a Comment