THE APRIL 2007 SWARM IN TRICHONIS LAKE USING DATA FROM A MICROSEISMIC NETWORK

PDF
Published: Jan 25, 2010
DOI: https://doi.org/10.12681/bgsg.11409
Keywords:
Trichonis Lake seismotectonics relocation double-difference clustering algorithms graph partitioning cross-correlation
E. Sokos
University of Patras, Department of Geology, Seismological Laboratory
V.E. Pikoulis
Department of Computer Engineering and Informatics, University of Patras
E.Z. Psarakis
Department of Computer Engineering and Informatics, University of Patras
A. Lois
University of Patras, Department of Geology, Seismological Laboratory
Abstract
A series of strong earthquakes took place at the Trichonis lake area, during April 2007. Three events, with M~5.0 occurred within one day, causing damages to almost all nearby villages and especially at the small town of Thermo. The sequence lasted for more than one month with small to moderate size events. It was recorded by regional networks and results related to its time and space evolution have already been published. Just after the major events a microseismic network was deployed in the area, by the University of Patras, Seismology Laboratory. Eight stations were installed, with short period, three component sensors and portable digital recorders. The network was in operation for a period of one month and a lot of events were recorded by enough stations to provide a reliable location. We present here the analysis of these data using modern methodologies like waveform cross-correlation techniques and further relocation of the events using waveform based differential time. The results partially support the findings of the regional networks, as regards the gross characteristics of the aftershock sequence, but provide an enhanced description of it. The space time evolution of the aftershock sequence reveals the activation of more than one fault in the area and suggests the connection of the sequence with an unmapped fault.
Article Details
  • Section
  • 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
Bardaine T., Gaillot P., Dudos-Sallee N., Blanco J., Senechal G. 2006. Characterization of Seismic Waveforms
and Classification of Seismic Events Using Chirplet Atomic Decomposition. Example from
the Lacq Gas Field (Western Pyrenees, France). Geophys. J. Int., 166, pp 699-718.
Becker D., T. Meier, M. Rische, M. Bohnhoff, H.P. Harjes. 2006. Spatio – temporal microseismicity clustering
in the Cretan region. Tectonophysics, 423, pp 3 – 16, 2006.
Cocard, M., Kahle, H.-G., Peter, Y., Geiger, A., Veis, G., Felekis, S., Paradissis, D., Billiris, H., 1999.
New constraints on the rapid crustal motion of the Aegean region: recent results inferred from GPS
measurements (1993–1998) across the West Hellenic Arc, Greece. Earth and Planetary Science Letters
, 39–47.
Doutsos, T., Kontopoulos, N., Frydas, D., 1987. Neotectonic evolution of northwestern continental Greece.
Geol. Rundsch. 76, 433–450.
Doutsos, T., Kokkalas, S., 2001. Stress and deformation patterns in the Aegean region. Journal of Structural
Geology 23, 455–472.
Evangelidis C. P., Konstantinou K. I., Melis N. S., Charalambakis M., Stavrakakis G. N., 2008, Waveform
relocation and focal mechanism analysis of an earthquake swarm in Trichonis lake, western
Greece, Bull. Seism. Soc. Am. 98(2), pp. 804-811.
Everitt, B. S., Landau S., Leese M. Cluster Analysis ( fourth edition). Arnold, London, 2001.
Fréchet, J., 1985. Sismogenèse et doublets sismiques. Thèse d’État, Université Scientifique et Médicale
de Grenoble, 206 pp.
Got, J.-L., Fréchet, J., Klein, F.W., 1994. Deep fault plane geometry inferred from multiplet relative location
beneath the south flank of Kilauea. J. Geophys. Res. 99, 15375–15386.
Haslinger, F., Kissling, E., Ansorge, J., Hatzfeld, D., Papadimitriou, E., Karakostas, V., Makropoulos, K.,
Kahle, H.G., Peter, Y., 1999. 3D crustal structure from local earthquake tomography around the Gulf
of Arta (Ionian region, NW Greece). Tectonophysics 304, 201–218.
Kiratzi, A., Sokos, E., Ganas, A., Tselentis, A., Benetatos, C., Roumelioti, Z., Serpetsidaki, A., Andriopoulos,
G., Galanis, O., Petrou, P., 2008. The April 2007 earthquake swarm near Lake Trichonis and
implications for active tectonics in western Greece, Tectonophysics 452, 51- 65.
Klein, F.W., 2002. User’s guide to HYPOINVERSE-2000, a FORTRAN program to solve earthquake locations
and magnitudes. U. S. Geological Survey Open File Report 02- 606, Version 1.0.
Lee, W. H. K., R. E. Bennett, and K. L. Meagher, 1972. A method of estimating magnitude of local earthquakes
from signal duration, Open File Report, U. S. Geological Survey, 28 pp.
Lee, W.H.K. and J.C. Lahr, 1975. HYPO 71: A computer program for determining hypocenter, magnitude,
and first motion pattern of local earthquakes. USGS Open file report, p75-311.
Lee, W. H. K. and C. M. Valdes, 1985. HYP071PC: A personal computer version of the HYPO71 earthquake
location program, U. S. Geological Survey Open File Report 85-749, 43 pp.
Lomax, A.J., 1991. User Manual for SeisGram. In Digital Seismogram Analysis and Waveform Inversion,
IASPEI Soft ware Library Volume 3, W.H.K. Lee, ed., Seismological Society of America.
Melis, N.S., Brooks,M., Pearce, R.G., 1989.Amicroearthquake study in the Gulf of Patras region, westXLIII,
No 4 – 2191
ern Greece, and its seismotectonic interpretation. Geophys. J. Int. 98, 515–524.
Paige C. C. and. Saunders M. A, 1982. LSQR: An algorithm for sparse linear equations and sparse least
squares, TOMS 8(1), 43-71.
Papazachos, C.B., Kiratzi, A.A., 1996. A detailed study of the active crustal deformation in the Aegean
and surrounding area. Tectonophysics 253, 129–153.
Pikoulis V.E., Psarakis E.Z., Sokos E.N. 2006. A New Two Step Correlation Based Technique for the
Classification of Seismic Events. Poster Section of First European Conference on Earthquake Engineering
and Seismology, Geneva, Sept.
Pikoulis V.E., Psarakis E.Z. and Sokos E.N. A Novel Seismic Data Processing Technique for the Event
Relocation Problem. Bulletin of the Seismological Society of America (to be submitted).
Psarakis E. and Evangelidis G. 2005. An Enhanced Correlation-Based Method for Stereo Correspondence
with Sub-Pixel Accuracy. Proc. of Inter. Conference on Computer Vision, ICCV05, pp.907-912,
Beijing.
Roumelioti, Z., A. Kiratzi and N. Melis, 2003. Relocation of the July 26, 2001 Skyros island (Greece)
earthquake sequence using the double-difference technique, Physics of the Earth and Planetary Interior,
Vol. 138, 231 - 239.
Waldhauser, F., , 2001. HypoDD: A computer program to compute double-difference hypocenter locations,U.S.
Geol. Surv. open-file report, 01-113, Menlo Park, California.
Waldhauser, F., Ellsworth, W.L., 2000. A double-difference earthquake location algorithm: method and
application to the Northern Hayward fault, California. Bull. Seismol. Soc. Am. 90, 1353–1368.
Wells, D.L., Coppersmith, K.J., 1994. New empirical relationships among magnitude, rupture length,
rupture width, rupture area, and surface displacement. Bull. Seismol. Soc. Am. 84, 974–1002.
Most read articles by the same author(s)