Abstract Title: Seperating Intrinsic and Scattering Attenuation using Rotational Sensor Recordings of Vibroseis Sweeps

Abstract Submitted to: SEISMOLOGY

Abstract Text:

Rotational motions which have significant importance on the field of seismology were not able to be directly recorded until recent years due to the lack of a portable and sensitive broadband rotational motion sensors. In addition to the three component translational motion observations, directly calculated rotational motions improved seismological studies. In order to further investigate and compare recently developed rotational sensors an experiment was made in Fürstenfeldbruck area. Since seperation of intrinsic and scattering attenuation is considered to be important to have detailed maps contributing to the lithological knowledge of targeted areas, we decided to investigate attenuation distribution around the experiment site via rotational and translational sensors. We benefited from Acoustic Radiative Transfer Theory to seperate the attenuation types. The inversion process requires S-wave coda, fair amount of earthquakes and a dense array of seismometers in order to have accurate 2D attenuation maps for different frequency bands. Within one week of experiment, there has been 36 earthquakes reported and only 7 of them were recorded by our rotational sensors. However, a vibroseis truck was also operating at the field and our sensors recorded 480 sweep signals. We used sweep signals as source for seperating intrinsic and scattering attenuation. Since vibroseis sweeps have rather small codas, we used water level deconvolution to obtain larger codas from source time function of the sweeps. Our preliminary results suggest that seperation of intrinsic and scattering attenuation with six degree of freedom (6 DoF) measurements is promising and useful since 6 DoF measurements provide array like results.