Document Type : Original Research Paper

Authors

• Vahid Maleki ¹
• mohammad reza Hatami ²
• Ali Asghar Mottaghi ³

¹ Ph.D. Institute of Geophysics, University of Tehran, Tehran, Iran

² Assistant Professor, Institute of Geophysics, University of Tehran, Tehran, Iran

³ Assistant Professor, University of Urmia, Urmia, Iran

Abstract

In this study, we investigate the seismicity of eastern Alborz based on precise location of the earthquakes during the last two decades. In order to reduce the effect of outliers and low quality data on earthquake location results, during phase reading, weighing has been done. Manual readings of seismic phases for the desired area have been provided with a seismic data bank in which 5461 phases S and 8523 phases have been read, compared to seismic phases read in The Iranian Seismological Center (IRSC) shows a significant increase. Initial location is based on phase picking and initial weights using a nonlinear probabilistic method (Lomax et al, 2000).
After calculation of initial location, the double difference method (waldhauser et al, 2000) is used to enhance the earthquake location quality. The earthquake waveform correlation tool is used to re-find the earthquakes. Transparency correlations are performed for events with a similarity of over 70% in a given time window for phase P and S. As a result, using this technique, the phase reading error for the same events reaches its lowest level, resulting in seismic events in re-location with a much higher accuracy than the initial location and location based only on the catalog data.
Results of waveform cross correlation shows that in this area, earthquakes with high similarity occurring at in different times. Investigating the location of earthquakes on the Firoozkouh fault and then Chashm fault and Astaneh Fault in the cross sections.

Keywords

• waveform cross correlation
• East Alborz
• phase picking
• Relocation

20.1001.1.10237429.1399.29.116.11.4

Main Subjects

• Geophysics