Reduction of electron temperature in low-latitude ionosphere at 600 km before and after large earthquakes

Oyama Koichiro, Yoshihiro Kakinami, Jann Yenq Liu, Masashi Kamogawa, Tetsuya Kodama

Research output: Contribution to journalArticle

51 Citations (Scopus)

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 languageEnglish
Article numberA11317
JournalJournal of Geophysical Research: Space Physics
Volume113
Issue number11
DOIs
Publication statusPublished - 2008 Nov 1

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Ionosphere
Electron temperature
earthquakes
tropical regions
ionospheres
ionosphere
Earthquakes
electrons
electron energy
electron
earthquake
ionosondes
disturbances
longitude
Satellites
earthquake epicenter
disturbance
temperature
Philippines
orbits

All Science Journal Classification (ASJC) codes

  • 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)
  • Space and Planetary Science
  • Palaeontology

Cite this

Koichiro, Oyama ; Kakinami, Yoshihiro ; Liu, Jann Yenq ; Kamogawa, Masashi ; Kodama, Tetsuya. / Reduction of electron temperature in low-latitude ionosphere at 600 km before and after large earthquakes. In: Journal of Geophysical Research: Space Physics. 2008 ; Vol. 113, No. 11.
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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 journalArticle

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