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pure and applied geophysics

, Volume 152, Issue 3, pp 465–505 | Cite as

The Erzincan (Turkey) Earthquake (Ms 6.8) of March 13, 1992 and its Aftershock Sequence

  • H. Grosser
  • M. Baumbach
  • H. Berckhemer
  • B. Baier
  • A. Karahan
  • H. Schelle
  • F. Krüger
  • A. Paulat
  • G. Michel
  • R. Demirtas
  • S. Gencoglu
  • R. Yilmaz

Abstract

—The Erzincan strike-slip earthquake of March 13, 1992 ruptured a section of the North Anatolian fault (NAF) at the northern margin of the Erzincan basin. The focal depth of about 10 km was less than given by ISC and NEIC. Erzincan and the surrounding villages were considerably damaged. In the Erzincan basin and in the neighbouring mountains a seismic network of ten stations was installed. It was operating continuously from March 21 through June 16, 1992. More than 3,000 aftershocks were recorded of which 505 could be located. The spectral parameters of 394 and the fault-plane solutions of 53 aftershocks were determined. For the given region the frequency dependent coda Q was derived as Q c = 122 f 0.68. The aftershock area increased with time, reflecting the process of stress redistribution. Some events clustered in the immediate vicinity of the town of Erzincan close to the epicentre of the main event and seem to trace the NAF. Their source mechanism is similar to that of the main event (strike slip). About 150 aftershocks clustered in the southeastern part of the Erzincan basin where a concentration of the events in a small volume of 5 × 5 × 3 km3 was observed. The majority of fault-plane solutions available for these aftershocks showed a normal faulting mechanism with an east-west directed extension. Most of the aftershocks southeast of the basin clustered between two lineaments that were mapped by satellite images. The P-wave velocity below the Erzincan basin, derived from travel-time residual analysis, is lower compared to areas NE and SW of the basin. Three-dimen sional stress modelling of the Erzincan region qualitatively explains the occurrence of the aftershocks southeast of the basin. The calculated displacement distribution which exhibits the north-westward motion of the basin and tension at its southeastern margin, caused by the Erzincan earthquake, is in agreement with derived fault-plane solutions.

Key words: Erzincan earthquake, North Anatolian fault, pull-apart basin, aftershocks. 

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Copyright information

© Birkhäuser Verlag Basel, 1998

Authors and Affiliations

  • H. Grosser
    • 1
  • M. Baumbach
    • 1
  • H. Berckhemer
    • 2
  • B. Baier
    • 2
  • A. Karahan
    • 2
  • H. Schelle
    • 1
  • F. Krüger
    • 3
  • A. Paulat
    • 2
  • G. Michel
    • 1
  • R. Demirtas
    • 4
  • S. Gencoglu
    • 4
  • R. Yilmaz
    • 4
  1. 1.GeoForschungsZentrum Potsdam, Telegrafenberg A31, 14473 Potsdam, Germany. Fax: +49 331 2881295, e-mail: grosgfz-potsdam.deDE
  2. 2.Institute of Meteorology and Geophysics of the Johann Wolfgang Goethe-Universität, Frankfurt am Main, Feldbergstraße 47, 60323 Frankfurt a. M., Germany.DE
  3. 3.Institute of Geosciences, University of Potsdam, PSF 601553, 14415 Potsdam, Germany.DE
  4. 4.Earthquake Research Department, General Directorate of Disaster Affairs, Eskisehir Yolu 10 km Lodumlu, Ankara, Turkey.TR

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