Abstract
We examine ionospheric electron temperatures (Te) observed by HINOTORI satellite during three earthquakes; M6.6 occurred in November 1981, M7.4 and M6.6 in January 1982 over Philippine, respectively. It is found that Te around the epicenters significantly decreases in the afternoon periods within 5 days before and after the three earthquakes. The region of ionosphere disturbance extends to 80-120 degrees in longitude. A tendency exists that duration of the disturbance becomes longer as the increase of earthquake magnitude. F2 peak frequency, f0F2 and virtual height, h'F from a chain of 4 ionosonde stations located in the longitude zone of 120°E-130°E are used together with electron density(Ne), that is observed simultaneously onboard HINOTORI satellite to find possible cause mechanisms of the abnormal reduction of electron temperatures. Behavior of HINOTORI Te/Ne and ionosonde f0F 2/h'F implies the existence of westward electric field over epicentre. Our finding suggests that simple two plasma instruments might be able to play a fundamental role to study ionosphere disturbance associated with earthquake, if the constellation of small/mini satellites is organized and the orbits are properly chosen.
| Original language | English |
|---|---|
| Article number | A11317 |
| Journal | Journal of Geophysical Research: Space Physics |
| Volume | 113 |
| Issue number | 11 |
| DOIs | |
| Publication status | Published - 2008 Nov 1 |
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- Geophysics
- Forestry
- Oceanography
- Aquatic Science
- Ecology
- Water Science and Technology
- Soil Science
- Geochemistry and Petrology
- Earth-Surface Processes
- Atmospheric Science
- Earth and Planetary Sciences (miscellaneous)
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Reduction of electron temperature in low-latitude ionosphere at 600 km before and after large earthquakes. / Koichiro, Oyama; Kakinami, Yoshihiro; Liu, Jann Yenq; Kamogawa, Masashi; Kodama, Tetsuya.
In: Journal of Geophysical Research: Space Physics, Vol. 113, No. 11, A11317, 01.11.2008.Research output: Contribution to journal › Article
TY - JOUR
T1 - Reduction of electron temperature in low-latitude ionosphere at 600 km before and after large earthquakes
AU - Koichiro, Oyama
AU - Kakinami, Yoshihiro
AU - Liu, Jann Yenq
AU - Kamogawa, Masashi
AU - Kodama, Tetsuya
PY - 2008/11/1
Y1 - 2008/11/1
N2 - We examine ionospheric electron temperatures (Te) observed by HINOTORI satellite during three earthquakes; M6.6 occurred in November 1981, M7.4 and M6.6 in January 1982 over Philippine, respectively. It is found that Te around the epicenters significantly decreases in the afternoon periods within 5 days before and after the three earthquakes. The region of ionosphere disturbance extends to 80-120 degrees in longitude. A tendency exists that duration of the disturbance becomes longer as the increase of earthquake magnitude. F2 peak frequency, f0F2 and virtual height, h'F from a chain of 4 ionosonde stations located in the longitude zone of 120°E-130°E are used together with electron density(Ne), that is observed simultaneously onboard HINOTORI satellite to find possible cause mechanisms of the abnormal reduction of electron temperatures. Behavior of HINOTORI Te/Ne and ionosonde f0F 2/h'F implies the existence of westward electric field over epicentre. Our finding suggests that simple two plasma instruments might be able to play a fundamental role to study ionosphere disturbance associated with earthquake, if the constellation of small/mini satellites is organized and the orbits are properly chosen.
AB - We examine ionospheric electron temperatures (Te) observed by HINOTORI satellite during three earthquakes; M6.6 occurred in November 1981, M7.4 and M6.6 in January 1982 over Philippine, respectively. It is found that Te around the epicenters significantly decreases in the afternoon periods within 5 days before and after the three earthquakes. The region of ionosphere disturbance extends to 80-120 degrees in longitude. A tendency exists that duration of the disturbance becomes longer as the increase of earthquake magnitude. F2 peak frequency, f0F2 and virtual height, h'F from a chain of 4 ionosonde stations located in the longitude zone of 120°E-130°E are used together with electron density(Ne), that is observed simultaneously onboard HINOTORI satellite to find possible cause mechanisms of the abnormal reduction of electron temperatures. Behavior of HINOTORI Te/Ne and ionosonde f0F 2/h'F implies the existence of westward electric field over epicentre. Our finding suggests that simple two plasma instruments might be able to play a fundamental role to study ionosphere disturbance associated with earthquake, if the constellation of small/mini satellites is organized and the orbits are properly chosen.
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UR - http://www.scopus.com/inward/citedby.url?scp=58749114441&partnerID=8YFLogxK
U2 - 10.1029/2008JA013367
DO - 10.1029/2008JA013367
M3 - Article
AN - SCOPUS:58749114441
VL - 113
JO - Journal of Geophysical Research: Space Physics
JF - Journal of Geophysical Research: Space Physics
SN - 2169-9380
IS - 11
M1 - A11317
ER -