INVESTIGATING OF RELATIVE CRUSTAL THICKNESSES VARIATION OF CRETAN REGION WITH MAGNETIC AND FREE AIR GRAVITY ANOMALIES
Year 2009,
Volume: 11 Issue: 1, 44 - 56, 01.01.2009
Tolga Gönenç
Mustafa Akgün
Mustafa Ergün
Abstract
Cretan Arc area where the plates of Africa and Aegean converge, is an active subduction still undergoing.
In this respect the Cretan Arc is one of the most complex within the Eastern Mediterranean tectonics. In order to
explain this structure, the crustal structure of this area lying in the coordinates 230
00ı
-280
00ı
east longitudes
and 330
00ı
-360
40ı
north latitudes was tried to be investigated with free-air gravity and magnetic anomalies.
There is a reciprocal relationship between the anomalies for determining crustal thicknesses. Therefore this
approach can give general information about relative crustal thicknesses. The crustal thickness are thicker in
the south of the Island of Crete compared with its north and accordingly the crustal thickness get relatively
thinner toward the inward of the Aegean Sea observed from the both gravity and magnetic anomalies.
References
- Benetatos C., Kiratzi A., Papazachos C. and Karakaisis G. (2004): “Focal mechanisms of shallow and intermediate depth earthquakes along the Hellenic Arc”, Journal of Geo Dynamics 37 pp:253-296.
- Brönner, M. (2003): “Untersuchung des Krustenaufbaus entlang des Mediterranen Rückens abgeleitet aus geophysikalischen Messungen. In: Berichte aus dem Zentrum für Meeres und Klimaforschung” Reihe C: Geophysik Nr. 21. Universitat Hamburg, p. 170.
- Bohnhoff, M.,Makris, J., Papanikolaou, D. and Stavrakakis, G. (2001): “Crustal investigation of the Hellenic subduction zone using wide aperture seismic data”, Tectonophysics 343 (3–4), 239–262.
- Casten, U., Snopek, K. (2006): “Gravity modelling of the Hellenic subduction zone—a regional study”, Tectonophysics 417 183–200.
- Delibasis, N., Ziazia, M., Voulgaris, N., Papadopoulos, T., Stavrakakis, G., Papanastassiou, D. and Drakatos, G. (1999): “Microseismic activity and seismotectonics of Heraklion area (central Crete Island, Greece).” Tectonophysics 308, 237–248.
- Payo, G. (1967): “Crustal structure of the Mediterranean sea by surface waves”, Part I. Group velocity. Bull. Seismol. Soc. Am., 57, 151-172.
- Snopek, K., Meier, T., Endrun, B., Bohnhoff, M. and Casten, U. (2007): “ Comparison
of gravimetric and seismic constrains on the structure of the Aegean lithosphere in hthe
forearc of the Hellenic subduction zone in the area of Crete”, Jourmal Of Geodynamics., 44- 173,187
- Stiros, S.C. (2000): “TheAD365 Crete earthquake and possible seismic clustering during the fourth to sixth centuriesADin the Eastern Mediterranean: a review of historical and archaeological data.” J. Struct. Geol. 23, 545–562.
- Taymaz, T., Jackson, J. and Westaway, R., (1990): “Earthquake mechanism in the Hellenic Trench near Crete”, Geophysical Journal International 102, 695– 731.
- Von Frese, R.R.B., W.J. Hinze and L.W. Braile, (1982). “Regional North American gravity and magnetic anomaly correlations”, Geophys. J.R. Astr. Soc., v. 69, pp. 745-761.
- Woodside, J. M. and Bowin, C. (1970): “Gravity anomalies and inferred crustal structures in eastern Mediterranean Sea”, Geol. Soc. Amer. Bull. 81, 1107.
GİRİT BÖLGESİNİN İZAFİ KABUK KALINLIĞI DEĞİŞİMİNİN MANYETİK VE SERBEST HAVA GRAVİTE ANOMALİLERİ İLE İRDELENMESİ
Year 2009,
Volume: 11 Issue: 1, 44 - 56, 01.01.2009
Tolga Gönenç
Mustafa Akgün
Mustafa Ergün
Abstract
Girit yayı bölgesi Doğu Akdeniz’de aktif dalma-batma olgusunun devam ettiği Afrika ve Ege levhalarının
etkileştiği bir bölgedir. Bu bağlamda Girit yayı Doğu Akdeniz tektoniğinin en karmaşık alanıdır. Bu yapıyı
açıklamak için 230
00ı
-280
00ı
doğu boylamları ve 330
00ı
-360
40ı
kuzey enlemleri arasında kalan bölgenin
serbest hava gravite ve manyetik anomalilerinden kabuk yapısı araştırılmıştır.
Bu anomalilerin değerleri arasında kabuk kalınlıkları belirlenmesinde ters bir orantı mevcuttur. Dolayısıyla
bu yaklaşım göreceli kabuk kalınlıkları hakkında genel bilgileri vermektedir. Girit adasının güney kısmında
kabuk kalınlığı kuzeydekine göre daha fazla olduğu ve Ege Denizi içlerinde kabuk kalınlığının adanın güneyine
göre daha ince olduğu hem gravite hem de manyetik anomalilerin ortak değerlendirilmesi ile ortaya konmuştur.
Sonuç olarak bu uygulama özellikle göreceli kabuksal kalınlık değişiminin ilksel alan değerlendirmelerinde
yardımcı olacaktır.
References
- Benetatos C., Kiratzi A., Papazachos C. and Karakaisis G. (2004): “Focal mechanisms of shallow and intermediate depth earthquakes along the Hellenic Arc”, Journal of Geo Dynamics 37 pp:253-296.
- Brönner, M. (2003): “Untersuchung des Krustenaufbaus entlang des Mediterranen Rückens abgeleitet aus geophysikalischen Messungen. In: Berichte aus dem Zentrum für Meeres und Klimaforschung” Reihe C: Geophysik Nr. 21. Universitat Hamburg, p. 170.
- Bohnhoff, M.,Makris, J., Papanikolaou, D. and Stavrakakis, G. (2001): “Crustal investigation of the Hellenic subduction zone using wide aperture seismic data”, Tectonophysics 343 (3–4), 239–262.
- Casten, U., Snopek, K. (2006): “Gravity modelling of the Hellenic subduction zone—a regional study”, Tectonophysics 417 183–200.
- Delibasis, N., Ziazia, M., Voulgaris, N., Papadopoulos, T., Stavrakakis, G., Papanastassiou, D. and Drakatos, G. (1999): “Microseismic activity and seismotectonics of Heraklion area (central Crete Island, Greece).” Tectonophysics 308, 237–248.
- Payo, G. (1967): “Crustal structure of the Mediterranean sea by surface waves”, Part I. Group velocity. Bull. Seismol. Soc. Am., 57, 151-172.
- Snopek, K., Meier, T., Endrun, B., Bohnhoff, M. and Casten, U. (2007): “ Comparison
of gravimetric and seismic constrains on the structure of the Aegean lithosphere in hthe
forearc of the Hellenic subduction zone in the area of Crete”, Jourmal Of Geodynamics., 44- 173,187
- Stiros, S.C. (2000): “TheAD365 Crete earthquake and possible seismic clustering during the fourth to sixth centuriesADin the Eastern Mediterranean: a review of historical and archaeological data.” J. Struct. Geol. 23, 545–562.
- Taymaz, T., Jackson, J. and Westaway, R., (1990): “Earthquake mechanism in the Hellenic Trench near Crete”, Geophysical Journal International 102, 695– 731.
- Von Frese, R.R.B., W.J. Hinze and L.W. Braile, (1982). “Regional North American gravity and magnetic anomaly correlations”, Geophys. J.R. Astr. Soc., v. 69, pp. 745-761.
- Woodside, J. M. and Bowin, C. (1970): “Gravity anomalies and inferred crustal structures in eastern Mediterranean Sea”, Geol. Soc. Amer. Bull. 81, 1107.