an electric coupling model for the lithosphere-atmosphere-ionosphere system 1 seismology forum...
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An Electric Coupling Model for the Lithosphere-Atmosphere-Ionosphere System
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Seismology Forum Meeting 2014 :Recent Advances and New Findings in Seismology
L. C. Lee
March 19, 2014 Institute of Earth Sciences, Academia Sinica
Ionosphere density variations
[Liu et al., 2001]
Variations of fmF2 and TEC before Chi-Chi EQ
EQ
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Lithosphere – atmosphere – ionosphere couplingKuo, Huba, Joyce and Lee, JGR (2011, 2013)
Model of DC electric field generation in the ionosphere by seismic related EMF (electro-motive force) in the lower atmosphere. 1. Earth surface, 2. Conductive layer of
the ionosphere, 3. External electric current of EMF in the surface atmosphere, 4. Conductivity electric current in the atmosphere–ionosphere circuit, 5. DC electric field
in the ionosphere, 6. Field-aligned electric current, and 7. Charged aerosols injected into the atmosphere by soil gases (Sorokin and Hayakawa, 2013).
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The E field, current density J and induced charge density in the atmosphere
or = 0
(1)
(2)
(3)
(4)
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(5)
Electric coupling of lithosphere, atmosphere and ionosphere
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Kuo, Huba, Joyce and Lee, (JGR, 2011)
NRL 3D ionosphere simulation code (SAMI3)
• SAMI3 is a 3D low-latitude ionospheric model developed at the Naval Research Lab
• SAMI3 simulates the temporal and spatial evolution of seven ion species (H+,He+,N+,O+,N2
+,NO2+,O2
+) over the entire magnetic flux tube in both hemispheres
• The density and velocity equations are solved for all ion species.
• Ion temperature equation and electron temperature equations
• The altitude range is ±30° and the longitude range is 8° for our case
• The range of magnetic apex height is 85 to 2400 km19
Modified potential equation in SAMI3
(1)
(2) Use Dipolar Coordinates (dipole magnetic field
lines)
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Summary• The magnitude of current density Jrock is the most
important parameter to determine the TEC variations and nighttime bubble formation in the ionosphere.
• The current density Jrock = 10 - 100 nA/m2 in the earthquake fault zone can cause TEC variations of up to 2 – 20 % in daytime ionosphere.
• A current density Jrock = 1 - 10 nA/m2 can lead to nighttime TEC variations of 2 - 20 % as well as the formation of nighttime plasma bubble (equatorial spread F) extending over the whole magnetic flux tube containing the earthquake epicenter.
• Daytime and nighttime TEC variations and nighttime plasma bubbles within the affected region can be used as precursors for earthquake prediction.
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