Document Type : Original Research Paper

Authors

• M.S Mirabedini ¹
• M Agh-Atabai ²

¹ M. Sc. Student, Department of Geology, Faculty of Sciences, Golestan University, Golestan, Iran

² Assistant Professor, Department of Geology, Faculty of Sciences, Golestan University, Golestan, Iran

Abstract

In this research, to investigate seismic pattern and precursory properties of fractal dimensions, spatial distribution and temporal variations of correlation dimensions of epicentral, D_e, and temporal distribution of earthquakes, D_t, before the Baladeh-Kojour earthquake have been studied. The May 28^th, 2004, Baladeh-Kojour earthquake with M_b= 6.2 (ISC), which is one of the largest earthquake in the vicinity of Tehran, was occurred in the northern part of the Alborz mountain ranges. The spatial distribution maps show decreasing in D_e and D_t in the eastern part of the epicenter, which is observed at 2002 in the temporal variation plots. With respect to space-time plot, it seems that this decreasing caused by the earthquake clusters that were occurred between 2002 -2003. Investigation of seismic pattern based on spatial and temporal variations of fractal dimensions and space-time plot of earthquakes demonstrate doughnut pattern (some earthquake clusters and a lot of small events) and seismic quiescence before the main shock. The results indicate that fractal dimensions are sensitive to clustering in space and time. So, the spatial and temporal variations of these parameters can be used as a precursory phenomenon, which is caused by seismic activation and quiescence.

Keywords

• Fractal dimension
• Doughnut pattern
• Precursory
• Seismicity pattern
• Baladeh-Kojour earthquake