Soham Banerjee, Abhishek Kumar (2016), Determination of Seismic wave attenuation: A Review, Disaster Advances, Vol. 9 (6), 10-27

S wave and coda wave component for August 2008 Earthquake recorded at (a; Munsyari, Lat.: 30.066 N, Long.: 80.237 E), (b: Kapkot, Lat.: 29.941 N, Long.: 79.899 E) (Ref: Banerjee and Kumar, 2016)


Earthquake occurs when pent up energy is released during tectonic activities. This energy spreads in the form of waves and while propagating, these waves attenuate non-uniformly in different directions due to the variation in the elastic properties of the propagation medium. The recorded amplitudes of seismic waves are directly related to the attenuation properties of the medium. Compressional wave (P wave) and shear wave (S wave) are the primary waves (also known as direct waves) generated during an earthquake (EQ) and do significant damages within a certain range (200 km). Hence, attenuation studies for these waves are pretty much important in seismic hazard estimation. Various approaches has been developed worldwide to study the attenuation of these waves. In one of the approach, coda wave (back-scattered waves generated when direct waves interact with the medium heterogeneities) amplitudes are used to normalize the direct wave amplitudes in order to determine the frequency () dependent attenuation of direct waves. Obtained attenuation values can be used to understand the tectonic stability and medium heterogeneities of a region. Further, using these values intrinsic and scattering attenuations can be obtained separately in a region. In this study, a delineate discussion reviewing the properties of coda wave and coda normalization method (CNM) are given. In addition to CNM, two more methods in order to determine the attenuation of direct waves are also presented here. A detailed comparison in terms of assumptions made while developing each of the above methods is carried out here. Further, a detailed summary of various studies, addressing the attenuation characteristics of direct waves based on the above three methods is presented here. Regional characteristics such as medium heterogeneity, tectonic stability etc. evaluated by various researchers based on the direct wave attenuation are also discussed in this paper.

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