Seismicity - the Inner Earth

The Physics
of the
Dynamic Earth
Savage Earth

      Hewitt's Seismic Waves    
      Wave Motion L & T  
    Wave motion
Shear waves
Seismic Motion

      Wave Demo

Savage Earth Animations
Recent Earthquakes in California and Nevada
4-D Animation
Earth's Core
  Looking for A Stud!   Earth's Interior 2
  Earth's Interior    
              Here a Mantle. . .there a Core      
  Geophysical Techniques for Sensing Underground Structures     Gravitometrics
Ground-Penetrating Radar
Electrical Resistivity
Seismic Reflection/Refraction
Elemental Abundance Comparison
    Elemental Abundance Picture

The Elements of Life
It is reasonable to assume that life, wherever it might begin, would form itself out of the most abundant elements available to it. This does not mean that life based on such rare elements as holmium or hafnium could not exist, only that it would be very unlikely. In nature there are 85 stable elements (from hydrogen to uranium) and just four of them - hydrogen, carbon, nitrogen and oxygen - comprise more than 95% by weight of all living matter on Earth. Except for the gases helium and neon (which because of their inert nature do not form chemical compounds), these four elements are also the four most abundant elements in the universe. Curiously, they are not  the four most abundant elements on Earth (these are oxygen, iron, silicon and magnesium). In other words, the composition of living matter resembles the composition of the stars more than the planet we live on! Perhaps it is not surprising, therefore, that several people have proposed theories to suggest that life arrived on Earth rather than originated here (among them Lord Kelvin, Nobel prizewinner Francis Crick, and astrophysicist Fred Hoyle).

Elemental Abundance Chart

Plate Tectonics I II
Plate Tectonics is a relatively new theory that has revolutionized the way geologists think about the Earth. According to the theory, the surface of the Earth is broken into large plates. The size and position of these plates change over time. The edges of these plates, where they move against each other, are sites of intense geologic activity, such as earthquakes, volcanoes, and mountain building. Plate tectonics is a combination of two earlier ideas, continental drift and sea-floor spreading.
  Paul Hewitt/John Suchocki/Leslie Hewitt
The Southern Climate of Pangea was dominated by widespread glaciation. Paleomagmetic data suggests that Pangea was drifting as a unit across the South Pole.

    Ring of FireRing of Fire    
      Magnetic Pole Migration                
The study of the intensity and orientation of the earth's magnetic field as preserved in the magnetic orientation of certain minerals found in rocks formed throughout geologic time.

Paleomagnetic studies of rocks and ocean sediment have demonstrated that the orientation of the earth's magnetic field has frequently alternated over geologic time.
                          Magnetic Pole Reversal    
Hewitt's Magnetism
  Juan de Fuca
          "where are you?"
        Juan de Fuca Plate Magnetic Chart  
            Juan de Fuca Plate    
Mid-Atlantic Ridge
      Mid-Atlantic Ridge            
These are the
Magnetic Stripes
that are sensed using a magnetometer and a ship or plane passing over the
Mid-Atlantic ridge.
    Quantum Madness
Mid-Atlantic Ridge Magnetic Chart
Martian Magnetic Map