Deadly 7.2 Mag Earthquake Slams Haiti Hard

A very unusual and violent earthquake just hit Haiti late today.  Haiti is one of the poorest if not the poorest nation in the Americas.  Evidently, major public buildings were totally destroyed.  This is a great catastrophe for Haiti and it also has geological implications for many more people than just in Haiti, itself.  The last ten years has been a decade of geological action including some of the worst tsunamis ever recorded in the last 200 years.

ΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩ

Haiti earthquake: thousands feared dead – Telegraph

Haiti’s presidential palace and numerous other government buildings in the country’s capital Port-au-Prince collapsed after the tremor. A hospital was also flattened, with reports that patients were buried under the rubble. Karel Zelenka, a Catholic Relief Services representative in the capital of Port-au-Prince, told US colleagues before phone service failed that “there must be thousands of people dead,” according to a spokeswoman for the aid group, Sara Fajardo….The earthquake is the strongest ever to hit Haiti.

ΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩ

Haiti, like nearly all the smaller islands of the Caribbean, lies along the cutting edge of the Atlantic/Caribbean Plates.  This major earthquake as well as the strong aftershocks were all at the 10 km depth which is significant.  This seems to be a depth favored for earth shifting triggers in the lithosphere.  For example, the Great Boxing Day Quake that killed a quarter million people was at that depth, too.

ΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩ

IRIS – Seismic Monitor

The Caribbean Plate is most interesting for it sits dead center between the immense North American Plate and the immense South American Plate.  Like a nut caught in the jaws of a giant nutcracker, this plate is being relentlessly squeezed by the two slow but relentlessly moving landmasses.  Note in the map below, how half of Central America sits along the western edge of this peculiar plate!  The edge facing the Atlantic/North American plate has a lot of island building going on including a line of quite active and very dangerous volcanoes along the eastern subduction zone.

ΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩ

File:Tectonic plates Caribbean.png – Wikipedia, the free encyclopedia

I have been closely watching the increasingly active major faults in Northern California and the Gulf of Mexico.  Today’s map shows how active both ends are getting.  The middle section is totally still with nary a shiver as if some giant was holding it firm in place.  It will eventually reset, very violently, at least as violently as the Haiti earthquake today.

ΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩ

These IRIS maps show 2 weeks worth of quakes, the red circles are recent quakes, the yellow are more than 24 hours old.  Normally, there are virtually no yellow and very few red circles along the West Coast but for the last 2 months, there have been increasing activity along the entire length of the West Coast from the very disturbed Juan de Fuca plate all the way to the tip of Baja California.

ΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩ

This last two weeks, I have noticed lots of quakes along the length of the spreading rift zone between Europe, Africa and the North and South American plates.  But for this to create such a violent thunderclap of an earthquake in Haiti?  Well, last week, I noticed news about rising volcanic action in the island chains to the south of Haiti.  The incredible quake that slammed into Indonesia and which killed so many people several years ago is still causing the rest of the planet to shudder and rearrange itself.

ΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩ

It is also quite possible that glacial melt in Greenland may be contributing to this disorder.  Ice can and does compress landmasses and Greenland has been buried under incredible amounts of ice for at least a million years.  So it could be springing upwards, inch by inch.  Now, back to the interesting Caribbean Plate.  I didn’t know this, but recent research by geologists have some surprising ideas I think could be entertained as possible:

ΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩ

ScienceDirect – Tectonophysics : Sub-slab mantle flow parallel to the Caribbean plate boundaries: Inferences from SKS splitting

Sub-slab mantle flow parallel to the Caribbean plate boundaries: Inferences from SKS splitting

L.T. Piñero-Feliciangeli^a, and J.-M. Kendall^{b, ,}

.

^aInstituto de Ciencias de la Tierra, Universidad Central de Venezuela, Caracas, Venezuela

^bDepartment of Earth Sciences, University of Bristol, UK

Abstract

. Upper-mantle deformation near the margins of the Caribbean plate is investigated using observations of shear-wave splitting in teleseismic and local shear phases. The Caribbean plate is almost stationary in the hot-spot reference frame and is wedged between the North America, South America, Nazca and Cocos plates; collisional belts and major shear zones encircle the plate. Data from seismic stations operated by IRIS, GEOSCOPE, the Venezuelan Seismological Network, and the British Geological Survey have provided nearly 2000 seismic records for analysis. Analysis of shear-wave splitting in teleseismic core phases (e.g., SKS) at stations reveals fast shear-wave polarisations that are conformal to the plate boundary, paralleling the major structural features. The magnitude of the splitting is in general quite large (1.2–2.1 s). In northern Venezuela, the magnitude of splitting increases towards the Caribbean–South American collisional front.

ΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩ

Hot spots are most interesting.  We have no idea why they exist but there are many possible explanations.  One idea is, these are due to asteroid impact zones that shatter the lithosphere half a billion or more years ago and these remain ‘weak spots’ which are not part of the plates at all but lie below them.  For example, when India moved over one of these ‘hot spots’ it caused massive lava flows which are now called the Deccan Plains, there is a similar thing in Russia and Yellowstone seems to be a nasty hot spot, too.  Certainly, Hawaii is one. As the Pacific plate shifts, the hot spot is stationary and it leaves a chain of islands to show previous eruptions.

ΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩ

TECTONIC SIGNIFICANCE OF THE CARIBBEAN PLATE AS A REFERENCE FRAME SINCE XMA: THE “BACKBONE” EXPLAINED

DEWEY, John F., Department of Geology, UC Davis, Davis, CA 95616, jfdewey@ucdavis.edu and PINDELL, James, Dept. Earth Science, Rice University, Main Street, Houston, TX 77005

.

By 100Ma, the Costa Rica subduction zone initiated to trap the Caribbean Plate between the Central American and Lesser Antillean subduction zones. Since then, the Caribbean Plate has been trapped in the hot-spot (mantle) reference frame with respect to which the Americas have moved westward with leading edge flat compressional subduction. Subduction-accretion has occurred on both eastern and western sides of the Caribbean Plate in front of linear neutral arcs, whereas the Mexican arc is patchily and widely distributed with compressional subduction erosion and is moving westward in the Caribbean reference frame….

.

…Plate circuits give hotspot tracks on Pacific, Cocos, and Nazca Plates if the Caribbean Plate is fixed in the mantle frame.

ΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩ

Below is an older map from a decade ago showing how the Caribbean Plate was a big ‘rock’ in the time period 10 million years before the famous dinosaur-killing asteroid hit right up by the Yucatan.

Iturralde 2000 Caribbean plate model – 76 M

Perhaps that event caused the Caribbean plate to ooze out epic amounts of volcanic materials? And this contributed to the near-annihilation of many lifeforms? It is also interesting to see that the Yucatan is almost right next to Florida. Did the asteroid cause such rifts and cracks, that the Gulf of Mexico began to spread?

Below is a map showing another guess by other geologists.  It shows how it is being pinched by two subduction zones but the geologist puts a small question mark where the Caribbean plate faces the Pacific Ocean.  I wonder if some of the geological actions we see in the very restless western sides of both North and South America are partially due to trying to slip around this huge obstruction parked straight between them?  If these recent studies are true, this is one of the very few features on earth that don’t move!  But the grinding edges of this plate are certainly very violent and move quite unexpectedly.

ΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩΩ

Giunta et al. 1999 Caribbean plate model – Late Jurassic/Early Cretaceous

Email:

emeinel@fairpoint.net

MAILING ADDRESS:

EMS NEWS

P.O. BOX 483

BERLIN, NY 12022

Make checks out to ‘Elaine Supkis’

Click on the Pegasus icon on the right sidebar to donate via Paypal.