Abstract
Average source parameters for three large North Aegean events are obtained from body wave inversion for the moment tensor. The parameters for the events are as follows:
The events exhibit dextral strike-slip faulting with theT axis striking NS and nearly horizontal, implying extension in this direction. The focal mechanisms obtained are in agreement with the seismotectonic regime of the North Aegean. It is known that the region is tectonically controlled by the existence of the strike-slip Anatolian fault and its westward continuation in the Aegean, as well as the NS extension the whole Aegean area undergoes.
The components of the moment tensor show that the region is dominated by compression in the EW direction which is encompassed by extension in the NS direction. All the events were found to be shallow (≤10 km) with a source time function of approximately 8 s duration and small stress drop values.
The teleseismic long period verticalP-waves exhibited distortions, that could be attributed to lateral inhomogeneities in the source structure or more probably to a nonflat water-crust interface.
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References
Barker, G. B., andLangston, C. (1982),Moment Tensor Inversion of Complex Earthquakes, Geophys. J. R. Astr. Soc.68, 777–803.
Comninakis, P., andPapazachos, B. (1986),A Catalogue of Earthquakes in Greece and the Surrounding Area for the Period 1901–1985, Publication of the Geophysical Laboratory, University of Thessaloniki, No 1, 1986.
Jackson, J., andMcKenzie, D. (1988),The Relationship between Plate Motions and Seismic Moment Tensors, and the Rates of Active Deformation in the Mediterranean and Middle East, Geophys. J.93, 45–73.
Karacostas, B., Hatzidimitriou, P., Karakaisis, G., Papadimitriou, E., andPapazachos, B. (1986),Evidence for Long-term Precursors of Strong Earthquakes in the Northernmost Part of the Aegean Sea, Earthquake Pred. Res.4, 155–164.
King, G., andKiratzi, A. (1985),Forward Modelling of the December 17, 1981 North Aegean Event (unpublished data).
Kiratzi, A., Karakaisis, G., Paradimitriou, E., andPapazachos, B. (1985),Seismic-source Parameter Relations for Earthquakes in Greece, Pure Appl. Geophys.123, 27–41.
Langston, C. A. (1977),The Effect of Planar Dipping Structure on Source and Receiver Responses for Constant Ray Parameter, Bull. Seismol. Soc. Am.67, 1029–1050.
Langston, C. A. (1981),Source Inversion of Seismic Waveforms: The Koyna, India, Earthquakes of 13 September 1967, Bull. Seismol. Soc. Am.71, 1–24.
Langston, C., andHelmberger, D. (1975),A Procedure for Modelling Shallow Dislocation Sources, Geophys. J. R. Astr. Soc.42, 117–130.
LePichon, X., andAngelier, J. (1979),The Hellenic Arc and Trench System: A Key to the Neotectonic Evolution of the Eastern Mediterranean Area, Tectonophysics60, 1–42.
McKenzie, D. (1972),Active Tectonics of the Mediterranean Region, Geophys. J. R. Astr. Soc.30, 109–185.
McKenzie, D. (1978),Active Tectonics of the Alpine-Himalayan Belt: The Aegean Sea and Surrounding Regions. Geophys. J. R. Astr. Soc.55, 217–254.
Panagiotopoulos, D., andPapazachos, B. (1985),Travel Times of Pn Waves within the Aegean and Surrounding Area, Geophys. J. R. Astr. Soc.80, 165–176.
Papazachos, B., Kiratzi, A., Voidomatis, Ph., andPapaioannou, C. (1984),A Study of the December 1981–January 1982 Seismic Activity in Northern Aegean Sea, Boll. di Geof. Teor. ed Appl. XXVI, 101–102, 101–113.
Parazachos, B., Kiratzi, A., Hatzidimitriou, P., andKaracostas, B. (1986),Seismotectonic Properties of the Aegean Area that Restrict Valid Geodynamic Models, Wegener/Medlas Conference, Athens, May 14–16, 1986, 1–20.
Pavlides, S., Mountrakis, D., Kilias, A., andTranos, M. (1989),The role of strike-slip movements in the extensional area of Northern Aegean (Greece), Workshop onActive and Recent Strike-slip Tectonics, Florence Univ., 18–20 April 1989 (Abstr.).
Pavlin, G., andLangston, C. A. (1983),The Inverse Problem: Implications of Surface Waves and Free Oscillations for Earth Structure, Rev. Geophys. Space Phys.10, 251–282.
Rocca, A., Karakaisis, G., Karacostas, B., Kiratzi, A., Scordilis, E., andPapazachos, B. (1985),Further Evidence on the Strike-slip Faulting of the Northern Aegean Trough Based on Properties of the August–November 1983 Seismic Sequence, Boll. di Geof. Teor. ed Appl. XXVII, 106, 101–109.
Wiens, D. (1987),Effects of Near-source Bathymetry on Teleseismic P Waveforms, Geophys. Res. Lett. (in press).
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Kiratzi, A.A., Wagner, G.S. & Langston, C.A. Source parameters of some large earthquakes in Northern Aegean determined by body waveform inversion. PAGEOPH 135, 515–527 (1991). https://doi.org/10.1007/BF01772403
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DOI: https://doi.org/10.1007/BF01772403