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

Yıl 2014, Cilt: 6 Sayı: 3, 10 - 21, 01.09.2014

Mustafa Ulukavak Mualla Yalçınkaya

Öz

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.

Anahtar Kelimeler

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

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