Site characterizations for the Tehran network (TDMMO) in Tehran Region Using Micro-Earthquake, Microtremor and Quarry Blast Data

• H/V amplification functions in Tehran region.
• Three seismic sources (micro-earthquakes, microtremors and quarry blasts).
• Higher H/V ratios in quarry blasts due to importance of surface waves.
• H/V ratio method as a discrimination tool for quarry blasts.

We did a Study of Horizontal-to-Vertical Component Spectral Ratio in the Tehran seismic zone. Micro-earthquakes, microtremors and quarry blasts data were used as an estimation of the site response in the Tehran zone. Site effects were studied based on horizontal to vertical ratios by the Nakamura׳s technique. Also, we used the spectra of signals for three components with the lowest noise levels for spectral slope studies. The analysis used seismic events from a network of 13 seismic stations by the permanent local seismological network of the Tehran Disaster Mitigation and Management Organization (TDMMO) from 2004 to 2007. The number of events used were different for each station. Quarry blast events were with 1.2≤ML≤2.2 and micro-earthquakes were with 1.1≤ML≤4.1.By comparing results for earthquake, microtremor and quarry blast, we could see that there is a significant difference between them. The data showed clear observations, especially in high-frequencies. The H/V spectral ratios indicate dominant frequency for rock/soft site with a higher ratio level for quarry blast ratios, which are comparable to the earthquake results due to their difference sources. The results derived by spectral H/V ratios and spectral analysis may be used to distinguish between local earthquakes and quarry blasts.