Seismo-Ionospheric Precursors
Abstract
Large earthquakes are often preceded or accompanied by signals of a different nature: electric, electromagnetic, or luminous, although seismic waves are the most obvious manifestation. Recently, seismo-ionospheric phenomena have received considerable discussions. To investigate possible seismo-ionospheric precursors, we statistically examine the relationship between electron density variations at the ionospheric F2 peak observed by a local ionosonde and 184 earthquakes with magnitude 5.0 or larger, which occurred in 170 days during 1994~1999 in the Taiwan area. Results demonstrate that the electron density abnormally decreases during the afternoon period, 1200~1800 LT, within 5 days before the earthquakes. The odds of the earthquakes with the precursor increasing in the earthquake magnitude but decreasing in the range between the epicenter and the ionosonde confirm the existence of an imminent seismo-ionospheric precursor.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2003
- Bibcode:
- 2003AGUFM.T51E0207L
- Keywords:
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- 2427 Ionosphere/atmosphere interactions (0335);
- 2435 Ionospheric disturbances;
- 7223 Seismic hazard assessment and prediction;
- 8159 Rheology: crust and lithosphere