 |
| Titel |
Ionosperic anomaly due to seismic activities – Part 1: Calibration of the VLF signal of VTX 18.2 KHz station from Kolkata and deviation during seismic events |
| VerfasserIn |
S. Sasmal, S. K. Chakrabarti |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1561-8633
|
| Digitales Dokument |
URL |
| Erschienen |
In: Natural Hazards and Earth System Science ; 9, no. 4 ; Nr. 9, no. 4 (2009-08-11), S.1403-1408 |
| Datensatznummer |
250006902
|
| Publikation (Nr.) |
 copernicus.org/nhess-9-1403-2009.pdf |
|
|
|
|
|
| Zusammenfassung |
| VLF signals are long thought to give away important information about the lithosphere-ionosphere
coupling. In order to establish co-relations, if any, between the ionospheric activities
and the earthquakes, we need to understand what the reference signals are, throughout
the year. The best opportunity to do this is during the period of solar minimum
where the number of flares and sunspots are negligible and the data would be primarily
affected by the sun and variation would be due to normal sunset and sunrise effects.
In this paper, we present the result of the sunrise and sunset terminators
as a function of the day of the year for a period of four years, viz,
2005–2008 when the solar activity was very low. The terminators
are for the 18.2 KHz VTX signal of the Indian Navy as observed from Indian Centre
for Space Physics receiving station located in Kolkata. A total of 624 days of data
have been used to obtain the mean plot. Any deviation of observations from this so-called
the standardized calibration curve would point to influences by terrestrial
(such as earthquakes) and extra-terrestrial events (such as solar activities).
We present examples of deviations which occur in a period of 16 months and show that
the correlation with seismic events is significant and typically the highest deviation
takes place up to a couple of days prior to the seismic event.
Simultaneous observations of such deviations from more than one station could improve the
predictability of earthquakes. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|