Introduction, Plate Tectonics, and Geodynamics

08/28/18:
  • Early identification of continents as puzzle pieces

    Antonio Snider-Pellegrini's 1858 lithographic illustration of the opening of the Atlantic Ocean. This is often considered the 1st known illustrative representation of the fit between Africa and South America.

  • Magnetic Stripes Anomalies and the Paleomagnetic record

    JDF Stripes image source, Paleomag. image source.

  • Cocos Plate

    From this image, the relative plate motions are obvious, and because the absolute pole of Cocos plate rotation is near, the transform faults and ocean ridges for clear small and great circles identifying the pole.

  • Ocean Floor and Land Physiography


  • Age of the Sea Floor (derived from magnetic anomalies)

    Image from (http://www.ngdc.noaa.gov/mgg)

  • Schematic Ridge


  • East Pacific Rise Transforms new 9° North


  • Sea Level over time

  • source

  • Schematic Transform Fault


  • Gorda Ridge and Mendacino Triple Junction


  • Anatolian Fault


  • Transforms Near Populations

    [left] The San Andreas Fault (red line) runs just west of more than 7,000,000 people in the San Francisco Bay. A large, possibly Mw 7.8 earthquake devistated San Francisco in 1906. [right] The Northern Anatolian Fault (red) run by Ankara (almost 4,000,000) before running along Istanbul, a massive city of more than 12,000,000 inhabitants. Some geophysicists suspect there is a significant likelihood of a Mw 7.6 event near Istanbul by 2030.- By all acounts, this event is expected to be devestating.


  • Schematic Subduction Zone


  • Middle America Trench (prominent erosional trench)


  • Cascadia Trench (invisible trench with accretionary wedge)


  • Cocos Plate (Euler Rotation Visualized)

    From this image, the relative plate motions are obvious, and because the absolute pole of Cocos plate rotation is near, the transform faults and ocean ridges for clear small and great circles identifying the pole.

  • Western Pacific (Visible hotspot trend, with bend)

    The track of the Emperor Seamount Chain running west from Hawaii, shows the "absolute" path of the Pacific Plate relative to the theoretically stable hotspot. Note the big bend in the chain corresponding to a major plate-motion reorientation about 30 Ma.

  • Hemispheric Projection of Plate Motions with Earthquakes

    Plate motions are shown relative to a "No Net Rotation (NNR)" reference frame. Meaning that the spatially weighted mean motion of all plates is zero. Large Nazca and Cocos Plate Motions are approximately 10 mm y-1.



  • GeoMappApp a physiographic earth viewer

09/06/18:
  • Earth's Magnetic Field Orientation

    (from Fowler Figure 3.3.a)

  • Changes in Earth Magnetic field over recent history


  • Geodynamo Modeling (From G. Glatzmeier at UCSC):
    Before a reversal:
    		 During a reversal:
    Lines are representations of the geomagnetic field with color representing north and south pole orientations. More information can be found here.

  • The Magnetic Field of the Earth Interacts with Solar Wind, protecting us from most solar radiation


  • Geomagnetic Time Scale:

    C and M represent the Cenozoic and Mesozoic eras. This figure is repeated in Fowler, Figure 3.14, and is taken from here.

  • Apparent Polar Wander:

    Example of North American and Eurasian Plates between 450 to 150 Ma (Middle Ordovician to Middle/Late Jurassic).

  • Magnetic Stripes on the Ocean Floor:

    Data was first published in Raff and Mason (GSAB, 1961) and figure is taken from here.

  • Magnetic Stripes on the Ocean Floor:

    Figure taken from here.

  • Plate Reconstructions to 750 Ma:
    locally.
    PPT taken from here.

09/11/18:
  • LAGEOS Missions
    More info at NASA


  • More information on NASA's use of Satellite Laser Ranging (SLR) to track the Lunar Reconnaissance ORbiter (LRO) can be found here.

  • VLBI at NASA

  • GPS-derived Plate motions (REVEL)

    Similar to the geologically-derived (NUVEL1a), but with data collected over motions from just 10-15 years, rather than over 1 Ma. Interestingly, away from active plate boundaries, results are consistent at about 97%.

  • Complex motions of Microplates show details of Euler and continental motions



  • Current Global GPS velocities
  • North American Plate Motion
    (from Calais et al., 2006)
  • After removing Euler motion, left with residual motion (mostly isostatic rebound)
    (from Sella_et al.,_2007)

    GPS and InSAR processing
  • My pages describing GPS data reduction using Gamit.
  • My pages describing InSAR processing using ROI_PAC.

  • InSAR image or deformation due to the Hector Mine Earthquake in October of 1999.

  • Western US InSAR Consortium page

  • LIDAR Imaging during recent activity at Mount St. Helens in Sept and November 2004

    from USGS
Intro. to Geophysics: Supp. | Intro. to Geophysics: Home | Updated: Tue Sep 11 14:39:48 EDT 2018