Moment Tensor Solution of Qom Main-shock and the Major Aftershock Based on Waveform Modeling of INSN Broadband Data

Based on Waveform Modeling of INSN Broadband Data

 

 

Moment tensor solution of the main shock and the only aftershock with magnitude above 4 (Mw) are presented here. The modeling has been carried out using Dreger’s (Dreger 2003) method which is based on time domain, full waveform three component modeling of seismograms for obtaining the components of seismic moment tensors. The data comprise broadband recordings of 4 stations of Iran National Seismic Network (INSN) within regional distances from the analyzed events. Locations of the events and the waveform fits are presented below. The solutions show mainly reverse faulting with some component of strike slip movements.

 

1- The Main-shock

 

The main shock occurred on the afternoon of June 18th, 2007 and was measured 5.5 (mb) by IIEES and located about 150 km southwest of Tehran near the major city of Qom.

 

Location of the event , Waveform fit

 

2- The Major aftershock

 

Most of the aftershocks recorded in the aftermath of the main event have been small magnitude quakes. Only one aftershock a day after the main shock was above 4 in magnitude and its solution is presented here.

 

Location of the event , Waveform fit

 

References

• Dreger, D. S., 2003. TDMT_INV: Time Domain Seismic Moment Tensor INVersion, International Handbook of Earthquake and Engineering Seismology, Volume 81B, p 1627.
• Engdahl, E.R., R. van der Hilst, and R. Buland, 1998. Global teleseismic earthquake relocation with improved travel times and procedures for depth determination, Bull. Seism. Soc. Am. 88, 722-743.

Location of the event

 

 

Waveform fit (Main-shock)

 

 

Waveform fit (Aftershock)