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Seismic Waves Reflected from Discontinuities within Earth's Upper Mantle.
Science (New York, N.Y.)
|January 10, 1969
Summary
Seismic wave reflections from Earth's upper mantle reveal a distinct 650 km deep transition zone. This discovery provides a global tool for studying the planet's internal structure.
Area of Science:
- Geophysics
- Seismology
- Earth Science
Background:
- Seismic waves, like PKPPKP, offer insights into Earth's deep interior.
- Understanding seismic wave precursors is crucial for mapping mantle structures.
Purpose of the Study:
- To investigate the origin of seismic wave precursors observed at specific distances.
- To confirm the existence and characteristics of a deep mantle transition zone.
Main Methods:
- Analysis of seismic wave precursors, specifically PKPPKP phases.
- Interpreting wave reflections originating from within the Earth's upper mantle.
Main Results:
- Observed precursors are attributed to reflections from Earth's upper mantle.
- Confirmed a sharply defined transition zone at approximately 650 km depth.
- This zone appears to be globally extensive.
Conclusions:
- The 650 km discontinuity is a significant feature of the upper mantle.
- These seismic data serve as a valuable tool for global upper mantle structure studies.
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