Is there any difference in local time variation in ionospheric F2-layer disturbances between earthquake-induced and Q-disturbance events?
Ionospheric anomalies before earthquakes have become the subject of one of the most intensive studies in the area of ionospheric variation. The ionosphere has a large class of disturbances under quiet geomagnetic conditions, i.e., quiet time disturbances (Q disturbances). Hence, the characterist...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2015-06-01
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| Series: | Annales Geophysicae |
| Online Access: | https://www.ann-geophys.net/33/687/2015/angeo-33-687-2015.pdf |
| Summary: | Ionospheric anomalies before earthquakes have become the
subject of one of the most intensive studies in the area of ionospheric
variation. The ionosphere has a large class of disturbances under quiet
geomagnetic conditions, i.e., quiet time disturbances (Q disturbances).
Hence, the characteristics of seismo-ionospheric anomalies obtained by
statistical analysis should be compared with those of Q-disturbance events.
Using the data of <i>fo</i>F2 (F2-layer critical frequency) during the whole interval of 1978–2008
(~3 solar cycles), the local time (LT) variation in Q disturbances
is investigated. The results showed that a well-pronounced nighttime peak
took place for positive disturbances induced by Q-disturbance events, while
positive disturbances related to earthquakes predominately occurred in the
daytime, especially in the afternoon LT sector. This remarkable difference
in local time variation in <i>fo</i>F2 between the earthquake-triggered and
Q-disturbance events is of great significance for the identification of
ionospheric precursors. |
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| ISSN: | 0992-7689 1432-0576 |