Seismo-ionospheric Precursors
Abstract
Various electromagnetic effects related to seismic activities have been reported previously in association with certain strong earthquakes. However, a demonstration that a seismo-ionospheric precursor is significant requires a large database. In this study, 184 earthquakes (with magnitude M>=5.0) that occurred within a radius of 500 km from Chung-Li during the period 1994 to 1999 are investigated. A robust statistical technique is applied to identify the precursory anomalies of the maximum ionospheric plasma frequency (foF2) observed during the same period from Chung-Li station. We have, for the first time, demonstrated statistically the existence of this seismo-ionospheric precursor. This analysis has uncovered not only the typical shape of seismo-ionospheric variations, but also a method for evaluating the reliability of the ionospheric precursors. The significance of the seismo-ionospheric precursors is further demonstrated by comparing the results with those obtained from a seismicity-based method for predicting earthquakes and is verified in contrast with the possible occurrence of foF2 precursor.
- Publication:
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AGU Spring Meeting Abstracts
- Pub Date:
- May 2002
- Bibcode:
- 2002AGUSM.S52A..01C
- Keywords:
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- 7223 Seismic hazard assessment and prediction;
- 7299 General or miscellaneous