pure and applied geophysics

, Volume 147, Issue 1, pp 147–159 | Cite as

Temporal variations in the fractal properties of seismicity in the North Anatolian Fault Zone between 31°E and 41°E

  • Ali Osman Öncel
  • Ian Main
  • Ömer Alptekin
  • Patience Cowie


We investigate the nature of temporal variations in the statistical properties of seismicity associated with the North Anatolian Fault Zone between longitudes 31°–41°E during the instrumental period 1900–1992. Temporal variations in the seismicb value and the fractal (correlation) dimensionD c of earthquake epicenters are examined for earthquakes of magnitudeM S ≥4.5, using sliding windows of 100 consecutive events.b varies temporally between 0.6 and 1.0, andD c between 0.6 and 1.4, both representing significant fluctuations above the errors in measurement technique. A strong negative correlation (r=−0.85) is observed betweenb andD c , consistent with previous observation of seismicity in Japan and southern California. Major events early in this century (M S ≥7) are associated with lowb and highD c , respectively consistent with greater stress intensity and greater spatial clustering of epicenters—both implying a greater degree of stress concentration at this time.

Key Words

Seismicity fractal dimension North Anatolian fault zone 


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Copyright information

© Birkhäuser Verlag 1996

Authors and Affiliations

  • Ali Osman Öncel
    • 1
    • 2
  • Ian Main
    • 2
  • Ömer Alptekin
    • 1
  • Patience Cowie
    • 2
  1. 1.Department of Geophysical EngineeringIstanbul UniversityIstanbulTurkey
  2. 2.Department of Geology and GeophysicsUniversity of EdinburghEdinburghUK

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