Introduction

This web page presents moment tensor inversion results for earthquakes with Iraq. The inversion technique is a grid search over the strike, dip and rake angles for each depth from 1 to 29 km in increments of 1 km. At each depth the combination of fault plane parameters which provided the best fit to the observed waveforms is selected. The final solution is the one which has best fit in terms of reduction of variance from all of the tested depths.

In order to perform the inversion, raw waveform data are converted to gruond velocity in units of meters/sec and are bandpass filtered in a frequency band that presents a coherent signal above either ground, site or instrumental noise. For many regions of the world, the 0.02 - 0.10 Hz band is used. However when the local velocity model is now well know, where significant path differences are expected or when the earthquake is large, a lower frequency band is selected.

This report presents the results of earthquake source parameters in Iraq and neighboring regions.

Inversions

• Inversion of the 2009/07/18 Sharqat, Iraq earthquake using the nnCIA velocity model
• Inversion of the 2009/07/18 Sharqat, Iraq earthquake using a local model derived by Ghassan Al-Equabi


• Inversion of the 2005/05/24 Syria earthquake
• Inversion of the 2008/12/01 Iran/Iraq border earthquake (not surface-wave solution preferred)

Comments

For the 2009/07/18 earthquake the nnCIA model provides a better fit to longer paths, while the Ghassan model does better at shorter distances. This is not surprising since the Ghassan model was derived using short distance paths to these same stations.