E-layer ionospheric disturbances following the Coalinga earthquake
A bistatic HF Doppler network in California recorded ionospheric disturbances after the Coalinga, California, earthquake of May 2, 1983. The ionospheric disturbances appear to be associated with acoustic waves launched vertically into the atmosphere from the ground motion caused by radially propagating surface seismic (Rayleigh) waves. The ionospheric disturbances were detected by variations in the frequency of the received transmissions (Doppler shifts); such disturbances have been observed in association with a number of previous earthquakes. The Doppler shifts were caused by phase path changes induced by the motion of the neutral atmosphere at the reflection height of the radio wave (200 km). We have also detected changes in the spectrum of the received transmissions following the Coalinga earthquake at the time of the passage of the acoustic waves through the E-layer. We interpret these spectral changes as an indication of specular reflection of the radio waves from index of refraction gradients induced by the acoustic waves, which have undergone significant nonlinear steepening during their propagation to 100 km. Since the acoustic waves were propagating upwards, the relections had negative Doppler shifts.
- Research Organization:
- Los Alamos National Lab., NM (USA)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 5962366
- Report Number(s):
- LA-10607-MS; ON: DE86008588
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
580201* -- Geophysics-- Seismology & Tectonics-- (1980-1989)
640201 -- Atmospheric Physics-- Auroral
Ionospheric
& Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CALIFORNIA
DOPPLER EFFECT
E REGION
EARTH ATMOSPHERE
EARTHQUAKES
ENVIRONMENTAL EFFECTS
FEDERAL REGION IX
GROUND MOTION
IONOSPHERE
MOTION
NORTH AMERICA
PLANETARY IONOSPHERES
SEISMIC EVENTS
SOUND WAVES
USA