COSEISMIC DEFORMATION AND SEISMIC FAULT OF THE 17 NOVEMBER 2015 M=6.5 EARTHQUAKE, LEFKADA ISLAND

PDF
Published: Jul 27, 2016
DOI: https://doi.org/10.12681/bgsg.11750
Keywords:
Greece Satellite GPS Lefkada
Ath. Ganas
National Observatory of Athens
P. Briole
University of California, Berkeley Seismological Laboratory
D. Melgar
University of California, Berkeley Seismological Laboratory
G. Bozionelos
National and Kapodistrian University of Athens
S. Valkaniotis
A. Avallone
INGV
G. Papathanassiou
E. Mendonidis
Aristotle University of Thessaloniki
P. Elias
National Observatory of Athens
Abstract

On November 17, 2015 a strong, shallow earthquake, Mw 6.5, occurred on the island of Lefkada along a strike-slip fault with right-lateral sense of slip. The event triggered widespread environmental effects that were mainly reported at the south and western part of the island while moving towards the eastern part, the intensity and severity of these earthquake-induced deformations were decreased. Relocation of seismicity and inversion of geodetic data suggests that the seismic fault runs parallel to the west coast of Lefkada, along the Aegean - Apulia plate boundary. The earthquake measured Mw=6.5 using the PGD relation of Melgar et al (2015, GRL). The fault plane strikes N20±5°E and dips to east with an angle of about 70±5 degrees. Coseismic deformation was measured in the order of tens of centimeters of horizontal motion by continuous GPS stations of NOANET (the NOA GPS network) and by InSAR (Sentinel 1A image pairs). Released interferograms from various groups show a large decorrelation area that extends almost along all the western coast of Lefkada, observation which provides strong support of landsliding. A coseismic slip model was produced from inversion of the ascending InSAR. We have not observed significant vertical motion of the shoreline and this is consistent with the predictions of the model.

Article Details
  • Section
  • Geophysics and Seismology
Creative Commons License

This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

Authors who publish with this journal agree to the following terms:

Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution Non-Commercial License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.

Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g. post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal. Authors are permitted and encouraged to post their work online (preferably in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work.

Downloads
Download data is not yet available.
References
Baker, C., Hatzfeld, D., Lyon-Caen, H., Papadimitriou, E. and Rigo, A., 1997. Earthquake
mechanisms of the Adriatic Sea and Western Greece: implications for the oceanic
subduction-continental collision transition, Geophysical Journal International, 131, 559-
Boncori, M.J.P., Papoutsis, I., Pezzo, G., Tolomei, C., Atzori, S., Ganas, A., Karastathis, V., Salvi,
S., Kontoes, C. and Antonioli, A., 2015, The February 2014 Cephalonia Earthquake
(Greece): 3D Deformation Field and Source Modeling from Multiple SAR Techniques,
Seismological Research Letters, January/February 2015, 86(1), 124-137.
http://dx.doi.org/10.1785/0220140126.
Bornovas, J., 1964. Géologie de l’île de Lefkade, Geol. Geophys. Res., Special Publication by Greek
Geological Survey, 10(1). Athens.
Cushing, M., 1985. Evolution structurale de la marge nord ouest helle´nique dans l’ıˆle de Levkas
et ses environs (Gre`ce nord occidentale). The`se 3me cycle, Univ. de Paris-Sud.
Ganas, A., Drakatos, G., Rontogianni, S., Tsimi, C., Petrou, P., Papanikolaou, M., Argyrakis, P.,
Boukouras, K., Melis, N. and Stavrakakis, G., 2008. NOANET: the new permanent GPS network
for Geodynamics in Greece, Geophysical Research Abstracts, Vol. 10, EGU2008-A-
Ganas, A., Chousianitis, K., Drakatos, G., Papanikolaou, M., Argyrakis, P., Kolligri, M., Petrou, P.,
Batsi, E. and Tsimi, C., 2011. NOANET: High-rate GPS Network for Seismology and
Geodynamics in Greece. Geophysical Research Abstracts, Vol. 13, EGU2011-4840, 2011,
EGU General Assembly 2011.
Ganas, A., Marinou, A, Anastasiou, D., Paradissis, D., Papazissi, K., Tzavaras, P. and Drakatos, G.,
GPS-derived estimates of crustal deformation in the central and north Ionian Sea,
Greece: 3-yr results from NOANET continuous network data, Journal of Geodynamics, 67,
-71.
Jacobshagen, V., 1979. Structure and geotectonic evolution of the Hellenides, Proc. VI Colloq
Aegean Region Athens, 1977, IGMR, Athens, 1355-1367.
Karakostas, V., Papadimitriou, E. and Papazachos, C., 2004. Properties of the 2003 Lefkada, Ionian
islands, Greece, Earthquake seismic sequence and seismicity triggering, BSSA 94/5:1976-
Lekkas, E., Danamos, G. and Lozios, S., 2001. Neotectonic structure and neotectonic evolution of
Lefkada Island, Bull. Geol. Soc. Greece, XXXIV/1, 157-163.
Louvari, Ε., Kiratzi, Α.Α. and Papazachos, B.C., 1999. The CTF and its extension to western
Lefkada Island, Tectonophysics, 308, 223-236.
Melgar, D., Crowell, B.W., Geng, J., Allen, R.M., Bock, Y., Riquelme, S., Hill, E.M., Protti, M. and
Ganas, A., 2015. Earthquake magnitude calculation without saturation from the scaling of
peak ground displacement, Geophys. Res. Lett., 42, doi: 10.1002/2015GL064278.
Papadopoulos, G.A., Karastathis, V.K., Ganas, A., Pavlides, S., Fokaefs, A. and Orfanogiannaki,
K., 2003. The Lefkada, Ionian Sea (Greece), shock (Mw 6.2) of 14 August 2003: Evidence
for the characteristic earthquake from seismicity and ground failures, Earth Planet. Space,
, 713-718.
Papathanassiou, G., Pavlides, S. and Ganas, A., 2005. The 2003 Lefkada earthquake: Field
observations and preliminary microzonation map based on liquefaction potential index for
the town of Lefkada, Engineering Geology, 82(1), 12-31.
Papathanassiou, G., Valkaniotis, S., Ganas, A. and Pavlides, S., 2013. GIS-based statistical analysis
of the spatial distribution of earthquake-induced landslides in the island of Lefkada, Ionian
Islands, Greece, Landslides, 10(6), 771-783.
Pavlides, S.B., Papadopoulos, G.A., Ganas, A., Papathanassiou, G., Karastathis, V., Keramydas, D.
and Fokaefs, A., 2004. The 14 August 2003 Lefkada (Ionian Sea) Earthquake, 5th
International Symposium on Eastern Mediterranean Geology, Thessaloniki, Greece, 14-20
April 2004, Reference T5-34.
Rondoyanni, Th., Sakellariou, M., Baskoutas, J. and Christodoulou, N., 2012. Evaluation of active
faulting and earthquake secondary effects in Lefkada Island, Ionian Sea, Greece: an
overview, Nat Hazards, 61, 843-860, doi: 10.1007/s11069-011-0080-6.
Sachpazi, M., Hirn, A., Clément, C., Haslinger, F., Laigle, M., Kissling, E., Charvis, P., Hello, Y.,
Lépine, J.-C., Sapin, M. and Ansorge, J., 2000. Western Hellenic subduction and Cephalonia
Transform: local earthquakes and plate transport and strain, Tectonophysics, 319, 301-319.
Valkaniotis, S., Ganas, A., Papathanassiou, G. and Papanikolaou, M., 2014. Field observations of
geological effects triggered by the January-February 2014 Cephalonia (Ionian Sea, Greece)
earthquakes, Tectonophysics, 630, 150-157.
Most read articles by the same author(s)