Fault complexity associated with the 14 August 2003 Mw6.2 Lefkada, Greece, aftershock sequence
The Mw6.2 Lefkada earthquake occurred on 14 August 2003 beneath the western coastline of Lefkada Island. The main shock was followed by an intense aftershock activity, which formed a narrow band extending over the western coast of the Island and the submarine area between Lefkada and Kefalonia Islands, whereas additional off fault aftershocks formed spatial clusters on the central and northwestern part of the Island. The aftershock spatial distribution revealed the activation of along-strike adjacent fault segment as well as of secondary faults close to the main rupture. The properties of the activated segments were illuminated by the precisely located aftershocks, fault plane solutions determination and the cross sections performed parallel and normal to their strike. The aftershock focal mechanisms exhibited mainly strike slip faulting throughout the activated area, although deviation of the dominant stress pattern is also observed. The results help to emphasize the importance of the identification of activated nearby fault segments possibly triggered by the main rupture. Because such segments are capable to produce moderate events causing appreciable damage, they should be viewed with caution in seismic hazard assessment in addition to the major regional faults.
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- Benetatos, C., A. Kiratzi, Z. Roumelioti, G. Stavrakakis, G. Drakatos, and I. Latoussakis (2005), The 14 August 2003 Lefkada Island (Greece) earthquake: Focal mechanisms of the mainshock and of the aftershock sequence, J. Seismology 9, 2, 171-190.
- Benetatos, C., D. Dreger, and A. Kiratzi (2007), Complex and segmented rupture associated with the 14 August 2003 Mw6.2 Lefkada, Ionian Islands, earthquake, Bull. Seism. Soc. Am. 97, 1B, 35-51.
- Hardebeck, J.L., and E. Hauksson (2001), Crustal stress field in southern California and its implications for fault mechanics, J. Geophys. Res. 106, B10, 21,859-21,882.
- Hatzfeld, D., V. Karakostas, M. Ziazia, G. Selvaggi, S. Leborgne, C. Berge, R. Guiguet, A. Paul, P. Voidomatis, D. Diagnourtas, I. Kassaras, I. Koutsikos, K. Makropoulos, R. Azzara, M. Di Bona, S. Baccheschi, P. Bernard, and C. Papaioannou (1997), The Kozani–Grevena (Greece) earthquake of 13 May 1995 revisited from a detailed seismological study, Bull. Seism. Soc. Am. 87, 2, 463-473.
- Karakostas, V. (2008). Relocation of aftershocks of the 2003 Lefkada Sequence: seismotectonic implications, Proc. 3rd Hellenic Conf. Earthq. Engin. & Engin. Seism., Athens, 5-7 Nov. 2008, CD ROM, 16 pp.
- Karakostas, V.G., E.E. Papadimitriou, and C.B. Papazachos (2004), Properties of the 2003 Lefkada, Ionian Islands, Greece, earthquake seismic sequence and seismicity triggering, Bull. Seism. Soc. Am. 94, 5, 1976-1981.
- Kiratzi, A.A., and C.A. Langston (1991), Moment tensor inversion of the 1983 January 17 Kefallinia event of Ionian islands (Greece), Geophys. J. Int. 105, 2, 529-535.
- Klein, F.W. (2002), User’s Guide to HYPOINVERSE-2000, a Fortran program to solve earthquake locations and magnitudes, U. S. Geol. Surv. Open File Report 02-171, Version 1.0.
- Louvari, E., A.A. Kiratzi, and B.C. Papazachos (1999), The Cephalonia Transform Fault and its extension to western Lefkada Island (Greece), Tectonophysics 308, 1-2, 223-236.
- Papadimitriou, E.E. (1993), Focal mechanism along the convex side of the Hellenic Arc, Boll. Geof. Teor. Appl. 35, 401-426.
- Papadimitriou, E.E. (2002), Mode of strong earthquake recurrence in the central Ionian Islands (Greece): Possible triggering due to Coulomb stress chan ges generated by the occurrence of previous strong shocks, Bull. Seismol. Soc. Am. 92, 8, 3293-3308.
- Papadimitriou, P., G. Kaviris, and K. Makropoulos (2006), The Mw = 6.3 2003 Lefkada earthquake (Greece) and induced stress transfer changes, Tectonophysics 423, 1-4, 73-82.
- Papadopoulos, G.A., V.K. Karastathis, A. Ganas, S. Pavlides, A. Fokaefs, and K. Orfanogiannaki (2003), The Lefkada, Ionian Sea (Greece), shock (Mw6.2) of 14 August 2003: Evidence for the characteristic earthquake from seismicity and ground failures, Earth Planets Space 55, 713-718.
- Papathanassiou, G., S. Pavlides, and A. Ganas (2005), The 2003 Lefkada earthquake: Field observations and preliminary microzonation map based on liquefaction potential index for the town of Lefkada, Eng. Geol. 82, 1, 12-31.
- Papazachos, B.C., and P.E. Comninakis (1971), Geophysical and tectonic features of the Aegean Arc, J. Geophys. Res. 76, 35, 8517-8533.
- Papazachos, B.C., and C.B. Papazachou (2003), The Earthquakes of Greece, Ziti Publications, Thessaloniki, 286 pp.
- Papazachos, B.C., E.E. Papadimitriou, A.A. Kiratzi, C.B. Papazachou, and E.K. Louvari (1998), Fault plane solutions in the Aegean sea and the surrounding area and their tectonic implication, Boll. Geof. Teor. Appl. 39, 3, 199-218.
- Reasenberg, P., and D. Oppenheimer (1985), FPFIT, FPPLOT and FPPAGE: FORTRAN computer programs for calculating and displaying earthquake fault-plane solutions, U.S. Geol. Surv. Open File Rep. 109, 85-730.
- Scordilis, E.M., G.F. Karakaisis, B.G. Karakostas, D.G. Panagiotopoulos, P.E. Comninakis, and B.C. Papazachos (1985), Evidence for trans form faulting in the Ionian sea: The Cephalonia island earthquake sequence of 1983, Pure Appl. Geophys. 123, 3, 388-397.
- Wessel, P., and W.H.F. Smith (1998), New, improved version of generic map ping tools released, Eos Trans. AGU 79, 47, 579.
- Zahradník, J., A. Serpetsidaki, E. Sokos, and A. Tselentis (2005), Iterative deconvolution of regional waveforms and a double-event interpretation of the 2003 Lefkada earthquake, Greece, Bull. Seism. Soc. Am. 95, 1 159-172.