Mislocation vectors for the Tripoli seismic array, Greece, and structural effect implications from backazimuth and slowness residual analysis

PDF (English)
Publiée : Jan 1, 2007
DOI : https://doi.org/10.12681/bgsg.16876
M. Pirli
National and Kapodistrian University of Athens, Faculty of Geology and Geoenvironment, Department of Geophysics - Geothermics
E. Pirlis
National and Kapodistrian University of Athens, Faculty of Geology and Geoenvironment, Department of Geophysics - Geothermics
N. Voulgaris
National and Kapodistrian University of Athens, Faculty of Geology and Geoenvironment, Department of Geophysics - Geothermics
Résumé

Tripoli Seismic Array, Greece, performance in terms of event location is restricted by its very small aperture and limited number of sensors. Detailed investigation of errors in automatic location results suggests structural and local geology effects. In order to investigate the possibility to correct for systematic errors automatically, mis location vectors were calculated for an extended data-set. Theoretical values were calculated based on earthquake catalogues compiled by the National Observatory of Athens and the ISC. Resulting mis location vectors are characterized by significant vector length, consistent with the large observed backazimuth and slowness residuals, the smaller values being met in the area NE of the array and for epicentral distance values less than 200 km. As expected, resulting corrections mostly concern backazimuth values and are not able to sufficiently affect the final epicentre solution, as the largest automatic algorithm errors are observed in epicentral distance determination. However, the possibility to automatically correct for systematic deviations is verified, and future research with an extended array configuration is expected to provide clearer results, due to significantly lower scatter.

Article Details
  • Rubrique
  • Geophysics and Seismology
Creative Commons License

Ce travail est disponible sous licence Creative Commons Attribution - Pas d’Utilisation Commerciale 4.0 International.

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.

Téléchargements
Les données relatives au téléchargement ne sont pas encore disponibles.
Références
Alexopoulos, J., 1998. A contribution to the investigation of the hydrogeological regime of the Tripoli plateau, using geophysical methods, PhD Thesis, University of Athens, Athens, 275pp. (in Greek)
Anderson, J., Farrell, W.E., Garcia, K., Given, J., and Swanger, H., 1990. Center for Seismic Studies Version 3 Database Schema Reference Manual, Technical Report C90-01, SAIC-90/1235, Science Applications International Corporation, San Diego, California, 64 pp.
Bratt, S.R., and Bache, T.C., 1988. Locating events with a sparse network of regional arrays, Bull. Seismol. Soc. Am., 78, 780-798.
Fyen, J., 1987. Improvements and modifications, NORSAR Sci. Rep. 2-86/87, NORSAR, Kjeller, Norway.
Fyen, J., 1989. Event Processor program package, NORSAR Sci. Rep. 2-88/89, NORSAR, Kjeller, Norway.
Harjes, H.-P., Jost, M.L., and Schweitzer, J., 1994. Preliminary calibration of candidate Alpha stations in the GSETT-3 network, Annali Geofisica, 37, 382-396.
ISC, 2006. International Seismological Centre On-line Bulletin, http://www.isc.ac.uk/Bull, Intern. Seis. Cent., Thatcham, United Kingdom.
Krüger, F., and Weber, M., 1992. The effect of low-velocity sediments on the mislocation vectors of the GRF array, Geophys. J. Int., 108, 387-393.
Kvaerna, T., and Doorbos, D.J., 1986. An integrated approach to slowness analysis with arrays and three-component stations, NORSAR Sci. Rep. 2-85/86, NORSAR, Kjeller, Norway, 60-69.
Kvasrna, T., and Ringdal, F., 1986. Stability of various f-k estimation techniques, NORSAR Sci. Rep. 1-86/87, NORSAR, Kjeller, Norway, 29-40.
Lin, C.-H., and Roecker, S.W., 1996. P-wave backazimuth anomalies observed by a small-aperture array at Pinyon Flat, Southern California: Implications for structure and source location, Bull. Seismol. Soc. Am., 86(2), 470-476.
Mariolakos, I., Papanikolaou, D., and Lagios, E., 1985. A neotectonic geodynamic model of Peloponnesus based on morphotectonics, repeated gravity measurements and seismicity, Geol. Jb., b50, 3-17.
Mykkeltveit, S., and Bungum, H., 1984. Processing of regional seismic events using data from small-aperture arrays, Bull. Seismol. Soc. Am., 74, 2313-2333.
Niazi, M., 1966. Corrections to apparent azimuths and travel-time residuals for a dipping Mohorovicic discontinuity, Bull. Seismol. Soc. Am., 56, 491-509.
Pirli, M., 2005. A contribution to earthquake location in Greece with the use of seismic arrays, PhD Thesis, University of Athens, Athens, 256 pp. (in Greek)
Pirli, M., Voulgaris, Ν., Alexopoulos, J., and Makropoulos, K., 2004. Installation and preliminary results from a small aperture seismic array in Tripoli, Greece, Bull. Geol. Soc. Greece, XXXVI, 1499-1508.
Pirlis, E., 2006. Evaluation of the automatic data processing algorithm and investigation ofcalibation possibilities for the Tripoli Seismic Array, MSc Thesis, University of Athens, Athens, 197 pp. (in Greek)
Schweitzer, J., 1992. The GERESS contribution to the GSETT-2 experiment 1991. In Advanced Waveform Research Methods for GERESS Recordings, DARPA Ann. Rep. No. AFOSR- 90-0189 Sci. Rep. No. 2, PL-TR-92-2142, ADA,253686,25-49.
Schweitzer, J., 1994. Mislocation vectors for small aperture arrays - A first step towards calibrating GSETT-3 stations, NORSAR Sci. Rep. 1-94/95, NORSAR, Kjeller, Norway, 104-118.
Schweitzer, J., 2001. Slowness corrections - One way to improve IDC products, PAGEOPH, 158, 375-396.
Wessel. P. and Smith, W.H.F., 1991. Free software helps map and display data, EOS Trans. Am. Geophys. Union, 72, 441, 445-446.
Wessel, P. and Smith, W.H.F., 1998. New, improved version of Generic Mapping Tools released, EOS Trans. Am. Geophys. Union, 79, 579.
Articles les plus lus par le même auteur ou la même autrice