Investigation Of Total Electron Content Variations Due To Earthquakes: Aegean Sea Earthquake (24.05.2014 Mw:6.5)

Abstract

GNSS satellites have been used as sensors with the development in space and satellite techniques. TEC variations in the ionosphere before, during and after the earthquake can be identified by means of GNSS observations. Thus, the effects of earthquakes over TEC variations can be monitored. For this purpose, the effects of the Aegean Sea earthquake (6.5 Mw), which is occured off Çanakkale in 24 May 2014 at 12:25:03 (-3 UT), are investigated. Pre-seismic and co-seismic TEC variations are examined in two campaigns. In the first campaign, 42-day (between DoY 115th and 156th) VTEC variations of the AYVL, IPSA and YENC stations are determined and used to monitor the ionospheric TEC variations before the earthquake. In the second campaign, the STEC data, which is calculated using three GPS satellite (GPS05, GPS08 and GPS15) observations from the AYVL, CANA and IPSA stations at DoY 144, is used to detect the ionospheric TEC variations at the time of the earthquake. In this study, 42-day Dst variation values, for before and after the earthquake, are examined in order to investigate the effects of the geomagnetic activity over TEC variations. As a result, has been concluded that no geomagnetic activity occured before and after the earthquake. In this context, VTEC anomalies before the earthquake are found to occur approximately 1-2 days before the earthquake. It is also found out that the short period variations affects the STEC values approximately 4-7 minutes after the earthquake. Keywords: GPS, Earthquake, Ionosphere, TEC, Time Series Analysis.

Keywords

• GPS, Earthquake, Ionosphere, TEC, Time Series Analysis

Deprem Kaynaklı Toplam Elektron İçeriği Değişimlerinin Araştırılması: Ege Denizi Depremi (24.05.2014 Mw:6.5)

Öz

Uydu ve uzay tekniklerinin gelişmesiyle GNSS uyduları birer sensor gibi kullanılmaya başlanmıştır. GNSS gözlemleri ile iyonosferdeki Toplam Elektron İçeriği (TEC) değişimleri deprem öncesi, deprem anı ve deprem sonrası belirlenebilmektedir. Böylece depremlerin TEC değişimlerine etkileri izlenebilmektedir. Bu amaçla çalışmada, Çanakkale açıklarında 24 Mayıs 2014 tarihinde, saat 12:25:03’te (-3 UT) meydana gelen Ege Denizi Depremi’nin (6.5 Mw) iyonosferde meydana getirdiği değişimler araştırılmıştır. Deprem öncesi, deprem anı ve deprem sonrası TEC değişimleri iki kampanyada araştırılmıştır. Birinci kampanyada AYVL, IPSA ve YENC istasyonlarının 115. ve 156. GPS günü arası toplam 42 günlük VTEC değişimleri belirlenmiş ve deprem öncesinde ortaya çıkan iyonosferik TEC değişimlerinin belirlenmesinde kullanılmıştır. İkinci kampanyada ise AYVL, CANA ve IPSA istasyonlarının 144. GPS gününde üç GPS uydusuna ait (GPS05, GPS08 ve GPS15) STEC değerleri deprem anında meydana gelen iyonosferik TEC değişimlerinin belirlenmesinde kullanılmıştır. Bu çalışmada, jeomanyetik aktivitenin TEC değişimlerine etkisini incelemek için deprem öncesi ve sonrasını içeren jeomanyetik aktivite (Dst) değerleri incelenmiş. deprem öncesinde ve sonrasında jeomanyetik aktivitenin olmadığı belirlenmiştir. Bu bağlamda, depremin meydana geldiği bu bölgede deprem öncesi VTEC değişimlerinin deprem gününden yaklaşık 1-2 gün öncesinde ortaya çıktığı, yapılan diğer çalışma sonucunda ise kısa periyotlu değişimlerin STEC değerlerine deprem anından yaklaşık 4 ile 7 dakika sonra etki ettiği görülmüştür. Anahtar Kelimeler: GPS, Deprem, İyonosfer, TEC, Zaman Serisi Analizi.

Anahtar Kelimeler

• GPS, Deprem, İyonosfer, TEC, Zaman Serisi Analizi

Kaynakça

1. Wyss M., 1997, “Second Round of Evaluations of Proposed Earthquake Precursors”, Pure and Applied Geophysics,149, 1997, 3-16.
2. Pulinets S. A., Boyarchuk K. A., 2004, “Ionospheric Precursors of Earthquakes”, Springer, New York, NY, USA, 2004.
3. Barnes R. A. and Leonard R. S., 1965, “Observations of ionospheric disturbances following the Alaska earthquake”, J GeophysRes 70: 1 250−1 253.
4. Liu, J. Y, Chen Y. I, Pulinets, S. A. and Chuo, Y. J., 2000a, “Seismo-ionospheric signatures prior to M>6.0 Taiwan earthquakes”. Geophys Res Lett 27(19): 3 113−3 116.
5. Liu J. Y, Chuo Y. J. and Chen Y. I., 2001b, “Ionospheric GPS TEC perturbations prior to the 20 September 1999”, Chi-Chi earthquake. Geophys Res Lett 28: 1 383−1 386.
6. Liu, J. Y., Chuo, Y. J., Shan, S. J., Tsai, Y. B., Chen, Y. I., Pulinets, S. A. and Yu, S. B., 2004, “Pre-earthquake ionospheric anomalies registered by continuous GPS TEC measurements”, Annales Geophysicae, 22, 2004, 5, 1585-1593, 10.5194/angeo-22-1585-2004.
7. Liu, J. Y., Chen, Y. I., Chuo, Y. J. and Chen, C. S., 2006, “A statistical investigation of preearthquake ionospheric anomaly”, Journal of Geophysical Research: Space Physics, 111, A5, 2156-2202, 10.1029/2005JA011333.
8. Pulinets S. A., 1998, “Strong earthquakes prediction possibility with the help of top side sounding from satellites”. Advances in Space Research 21(3): 455−458.

9. Dautermann T., Calais E, Haase J., and Garrison J., 2007, “Investigation of ionospheric electron content variations before earthquakes in southern California”, 2003–2004. J GeophysRes 12: 1 230−1 231.
10. Du P. R., Jiang H. R. and Guo Q. S., 1998, “Research on possibility of ionospheric anomalies as an earthquake precursor”. Earthquake18(2): 119−126 (in Chinesewith English abstract).
11. Singh, V.,Chauhan V., Singh O.P., and Singh B., 2010, “Ionospheric effect of earthquakes as determined from ground based TEC measurement and satellite data”, Indian J. of Radio& Space Phys., 39, 63-70, 2010.
12. Pulinets S., Kotsarenko, A.N., Ciraolo, L., and Pulinets, I.A., 2007, “Special case of ionospheric day today variability associated with earthquake preparation”, Adv. Space Res., 39, 970-977, 2007.
13. Dach, R., Hugentobler, U., Fridez, P. and Meindl, M., 2007, “Manual of Bernese GPS Software Version 5.0”. Astronomical Institute. University of Bern.
14. Leick, A., 2004, “GPS Satellite Surveying”. 3rd ed., John Wiley and Sons Inc., New Jersey.
15. Jin, R., Jin, S.G. and Feng, G.P., 2012, “M_DCB: Matlab code for estimating GNSS satellite and receiver differential code biases”, GPS Solut., 16(4), 541-548, doi: 10.1007/s10291-012-0279-3.
16. Komjathy, A., 1997, “Global Ionospheric Total Electron Content Mapping Using the Global Positioning System”. Ph.D. Thesis, Dept. of Geodesy and Geomatics Engineering Technical Report No. 188. Univ. of New Brunswick, Fredericton, New Brunswick, Canada.
17. Liao, X., 2000, “Carrier phase based ionosphere recovery over a regional area GPS network”. M.Sc. Thesis, Univ. of Calgary, Canada.
18. Makalea, J. J., Kelley, M. C., Sojka, J. J., Pi, X., and Manucci, A. J., 2001, “GPS normalization and preliminary modeling results of total electron content during midlatitude space weather event”. Radio Sci. 36, 356–361.
19. Warnant, R., 1997, “Reliability of the TEC computed using GPS measurements - The problem of hardware biases”. Acta Geod. Geoph. Hung. 32(3– 4), 451– 459.
20. Jakowski, N., Sardon, E., Engler, E., Jungstand, A., and Klahn, D., 1996, “Relationships between GPS-signal propagation errors and EISCAT observations”. Ann. Geophysicae. 14, 1429– 1436.
21. Komjathy, A., Langley, R., 1996, “An assesment of predicted and measured ionospheric total electron content using a regional GPS network”. paper presented at Nat. Tech. Meet., Inst. of Nav., Santa Monica, CA 22–24 January.
22. Lanyi, G. E., Roth, T., 1988, “A Comparison Of Mapped And Measured Total Ionospheric Electron Content Usin Global Positioning System And Beacon Satellite Observations”. Radio Sci., 23, 483–492.
23. Otsuka, Y., Ogawa, T., Saito, A., Tsugawa, T., Fukao, S. and Miyazaki, S., 2002, “A new technique for mapping of total electron content using GPS network in Japan”, Earth Planets Space, 54, 63–70.
24. Schaer, S., 1999, “Mapping and Predicting the Earth's Ionosphere Using the Global Positioning System”. Geodatisch-geophysikalische Arbeiten in der Schweiz, Vol. 59.
25. Wild, U., 1994, “Ionosphere and Geodetic Satellite Systems: Permanent GPS Tracking Data for Modeling and Monitoring”. Geodatisch-geophysikalische Arbeiten in der Schweiz, Vol. 48.
26. Jenkins, G.M. and Watts, D.G., 1968, “Spectral analysis and its applications”, Holden-Day series in time series analysis, Holden-Day.
27. Mills, T.C., 2011, “The Foundations of Modern Time Series Analysis”, Palgrave Macmillan perspectives in econometrics, Palgrave Macmillan, isbn:9780230290181.
28. Tsay, R. S., 2010, “Frontmatter, in Analysis of Financial Time Series”. Third Edition, John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470644560.fmatter
29. Chatfield C., 1996, “The Analysis Of Time Series”. Chapman & Hall/ CRC. 283 pp.
30. Erdogan H., and Arslan N., 2009, “Identification of vertical total electron content by time series analysis”. Digital Sig. Proc. Volume 19, Issue 4, July, Pages 740-749, ISSN 1051-2004, http://dx.doi.org/10.1016/j.dsp.2008.07.002.
31. http://sunum.hgk.msb.gov.tr/ TUSAGA-Aktif İstasyonlarına ait RINEX gözlem dosyaları (.14O), (Erişim Tarihi: 20 Temmuz 2014).
32. http://wdc.kugi.kyoto-u.ac.jp/dst_realtime/201404/index.html Kyoto Üniversitesi Jeomanyetizma ve Uzay Manyetizma Enstitüsü Veri Analiz Merkezi Jeomanyetik Aktivite Değişimi Değerleri (Dst) (Erişim Tarihi: 29 Temmuz 2014).
33. Loewe, C. A., Prölss, G. W., 1997, “Classification and mean behavior of magnetic storms”, J. Geophys. Res., 102(A7), 14209–14213, doi:10.1029/96JA04020.
34. Genceli, M., 1989, “Ekonometride İstatistik İlkeler”, Filiz Kitabevi, İstanbul.
35. Liu, J.Y., Chen, C.H., Chen, Y.I., Yang, W.H., Oyama, K.I. and Kuo, K.W., 2010, “A statistical study of ionospheric earthquake precursors monitored by using equatorial ionization anomaly of GPS TEC in Taiwan during 2001–2007“, Journal of Asian Earth Sciences, Volume 39, Issues 1– 2, 1 July 2010, Pages 76-80, ISSN 1367-9120, http://dx.doi.org/10.1016/j.jseaes.2010.02.012.