ACTIVE SEISMOTECTONIC STRUCTURES IN THE AREA OF CHIOS ISLAND, NORTH AEGEAN SEA, REVEALED FROM MICROSEISMICITY AND FAULT PLANE SOLUTIONS


Published: Jan 25, 2010
Keywords:
conjugate strike–slip and normal faults transition zone Chios Island North Aegean
V. G. Karakostas
E. E. Papadimitriou
M. D. Tranos
C. B. Papazachos
Abstract
Data from a digital seismological network operating during April–July 2002 were used for the microseismicity study of the area around Chios Island (East Aegean Sea, Greece). Numerous microearthquakes were detected and more than 950 well–located hypocenters were obtained along with 96 reliably determined focal mechanisms. The epicentral distribution and focal mechanisms of several earthquakes revealed that the NE–SW striking dextral strike–slip faults dominate in the study area as is the dominant pattern in North Aegean Sea. An earthquake swarm near Psara Island and a cluster offshore the west coast of Chios Island are associated with NW–SE trending left–lateral strike–slip faults, orthogonal to the dextral ones. Near the west coast of the Island the microseismicity evidences that oblique faulting dominates, whereas onshore and offshore the North Chios Island, clusters of events manifest the activation of either E–W or N–S striking normal faults. This complex deformation pattern is the manifestation of the dextral strike–slip faulting termination against conjugate sinistral ones, the transition from strike–slip to normal through the oblique faulting, as well as the activation of biaxial normal faulting in places.
Article Details
  • Section
  • Seismology
Downloads
Download data is not yet available.
References
Aktar, M., Karabulut, H., Özalaybey, S. and Childs, D., 2007. A conjugate strike –slip fault system
within the extensional tectonics of Western Turkey. Geophys. J. Int., 171, 1363–1375.
Altinok, Y., Alpar, B., Özer, N. And Gazioglu, C., 2005. 1881 and 1949 earthquakes at the Chios–Cesme
Strait (Aegean Sea) and their relation to tsunamis. Nat. Haz. & Earth Syst. Sci., 5, 717–725.
Besenecker, Η. Durr, S., Herget, G., Jacobshagen, V., Kauffmann, G., Ludtke, G., Roth, W. and Tietze,
K., 1968. Geologie von Chios (Agais). Geol. Paleontol., 2, 121–150.
Besenecker, Η. Durr, S., Herget, G., Kauffmann, G., Ludtke, G., Roth, W. and Tietze, K., 1971: Chios (2
sheets), Geological map of Greece at scale 1:50000, I. G. S. R., Athens.
Bozkurt, E., 2001. Neotectonics of Turkey – a synthesis. Geodan. Acta, 14, 3–30.
Cihan, M., Saraç, G. and Gökçe, O., 2003. Insights into biaxial extensional tectonics: an example from
the Sandikli graben, West Anatolia, Turkey. Geological J., 38, 47–66.
Karakostas, V. G., Papadimitriou, E. E., Karakaisis, G. F., Papazachos, C. B., Scordilis, E. M., Vargemezis,
G. and Aidona, E., 2003. The 2001 Skyros, Northern Aegean, Greece, earthquake sequence:
off–fault aftershocks, tectonic implications, and seismicity triggering, Geophys. Res. Lett.,
1029/2002GL015814.
Kilias, A. A., Mountrakis, D. M., Tranos, M. D. and Pavlides, S. B., 1998. The pre-volcanic metamorphic
rocks of Santorini Island: Structural evolution and kinematics during the Tertiary (South Aegean,
Greece). In: European Laboratory Volcanoes, Proc. 2nd workshop on Europ. Lab. Volcanoes, eds: R.
Casale, M. Fytikas, G. Sigvaldasson and G. Vougioukalakis, Europ. Comm., Sci. Res. Develop., 23–
Lee, W. H. K. and Lahr, J. C., 1975. HYPO71 (revised): A computer program for determining hypocenter,
magnitude and first motion pattern of local earthquakes, U. S. G. S. Open File Rep., 75–311.
Lister, G. S., Banga, G. & Feenstra, A., 1984. Metamorphic core complexes of Cordilleran type in the Cyclades,
Aegean Sea, Greece. Geology, 12, 221–5.
McClusky, S., Balassanian, S., Barka, A., Demir, C., Georgiev, I., Hamburger, M., Hurst, K., Kahle, H.,
Kastens, K., Kekelidze, G., King, R., Kotzev, V., Lenk, O., Mahmoud, S., Mishin, A., Nadariya, M.,
Ouzounis, A., Paradisis, D., Peter, Y., Prilepi, M., Reilinger, R., Sanli, I., Seeger, H., Tealeb, A., Toksoz,
M. N. and Veis, G., 2000. GPS constraints on crustal movements and deformations in the Eastern
Mediterranean (1988–1997): Implications for plate dynamics J. Geophys. Res., 105, 5695–5719.
McKenzie, D. P., 1970. The plate tectonics of the Mediterranean region. Nature, 226, 239–243.
McKenzie, D. P., 1972. Active tectonics of the Mediterranean region. Geophys. J. R. astron. Soc., 30,
–185.
McKenzie, D. P., 1978. Active tectonics of the Alpine–Himalayan belt: the Aegean Sea and surrounding
regions. Geophys. J. R. astron. Soc., 55, 217–254.
Ocakoğlu, N., Demirbağ, E. and Kuşçu, I., 2004. Neotectonic structures in the area offshore of Alaçati,
Doğanbey and Kuşadasi (western Turkey): evidence of strike–slip faulting in the Aegean extensional
province. Tectonophysics, 391, 67–83.
Panagiotopoulos, D. G., 1984. Travel time curves and crustal structure in the southern Balkan region. Ph.
D. Thesis, Univ. of Thessaloniki, pp. 173 (in Greek).
Papazachos, B. C. and Comninakis, P. E., 1970. Geophysical features of the Greek island arc and eastern
Mediterranean ridge. Com. Ren. Des Sceances de la Conference Reunie a Madrid, 1969, 16, 74–75.
Papazachos, B. C. and Comninakis, P. E., 1971. Geophysical and tectonic features of the Aegean arc. J.
Geophys. Res., 76, 8517–8533.
Papazachos, B. C. and Papazachou, C., 2003. The earthquakes of Greece. Ziti Publ., Thessaloniki, Greece,
pp.
Papazachos, B. C., Kiratzi, A. A. and Karakostas, V. G., 1997. Toward a homogeneous moment magnitude
determination in Greece and surrounding area. Bull. Seism. Soc. Am., 87, 474–483.
Papazachos, B. C., Papadimitriou, E. E., Kiratzi, A. A., Papazachos, C. B. and Louvari, E. K., 1998. Fault
plane solutions in the Aegean Sea and the surrounding area and their tectonic implications. Boll. Geof.
Teor. Appl., 39, 199–218.
Papazachos, B. C., Mountrakis, D. M., Papazachos, C. B., Tranos, M. D., Karakaisis, G. F., and Savvaidis,
A. S., 2001. The faults that caused the known strong earthquakes in Greece and surrounding
areas during 5th century B. C. up to present, 2nd Conf. Earthq. Engin. and Engin. Seism., 2–30 September
, Thessaloniki, 1, 17–26.
Papazachos, C. B., 1999. Seismological and GPS evidence for the Aegean–Anatolia interaction. Geophys.
Res. Lett., 26, 2653–2656.
Reasenberg, P. and Oppenheimer, D., 1985. FPFIT, FPPLOT and FPPAGE: Fortran programs for calculating
and displaying earthquake fault plane solutions. U. S. G. S., Open–File Rep., 95–515, 24pp.
Scordilis, Ε. Μ., 1985. Microseismicity study of the Servomacedonian zone and the surrounding area. Ph.
D. Thesis, Thessaloniki Univ., Greece, pp. 250 (in Greek with English abstract).
Seyitoğlu, G. and Scott, B. C., 1996. The cause of N–S extensional tectonics in western Turkey: tectonic
escape vs back–arc spreading vs orogenic collapse. J. Geodynamics, 22, 145–153, 1996.
Tranos, M. D., 2009. Faulting of Lemnos Island: a mirror of faulting of the North Aegean Trough (Northern
Greece). Tectonophysics, 467, 72–88.
Wessel, P. and Smith, W. H. F., 1998. New improved version of the Generic Mapping Tools released.
EOS, Trans. Am. Geophys. U., 79, 579.
Westaway, R., 1994. Evidence for dynamic coupling of surface processes with isostatic compensation in the
lower crust during active extension of western Turkey. J. Geophys. Res., 99, 20,203–20,233.
Zanchi, Α., Garzanti, E., Larghi, C., Angiolini, L. and Gaetani, M., 2003. The Variscan orogeny in Chios
(Greece): Carboniferous accretion along a Palaeotethyan active margin. Terra Nova, 15, 213–223.
Most read articles by the same author(s)