Matlab codes (Qbody) to study attenuation of seismic body-waves

The main disasters of geological origin are earthquakes, landslides, tsunamis and volcanic eruptions. Earthquake is the most dangerous among the disasters of geological origin. The destruction caused by an earthquake is directly related to its source (size) and indirectly related to the path travelled by the seismic waves. In order to mitigate the destruction, the knowledge of its source and path travelled by seismic waves is very important. The understating of these attributes of earthquakes is important for carrying various development activity such as, river valley projects, bridges and other construction works in the Himalayan region. Matlab codes (Qbody) have been developed to study the seismic wave attenuation characteristics. The frequency dependence relationships of quality factors for P-wave (Q?) and S wave (Q?) have been estimated by using extended coda wave normalization method in the frequency range 1.5 Hz to 24 Hz. A data set of 104 local earthquakes from Lower Siang region of Arunachal Himalaya has been investigated using these codes. The average variation in the estimated value of Q? and Q? are from 49 at 1.5 Hz to 1421 at 24 Hz and 118 at 1.5 Hz to 2335 at 24 Hz respectively. The frequency dependent relations for P and S-waves are (25±3) f (1.24±0.04) and (62±9) f (1.13±0.04) respectively. The value Q? and Q? obtained in the present study are comparable with the other seismically active regions of the world as well as of India. The obtained attenuation relations in the present study will be useful for simulation of strong ground motion and for estimation earthquake source parameters which have been further required for seismic hazard assessments in this region.