Attenuation of Coda Waves in Western Mexico Using Local Seismicity

Abstract

Coda waves are an important instrument to study the elastic properties of the lithosphere. The attenuation of coda waves in western Mexico is analyzed using seismograms recorded during the mapping of the Rivera subduction zone experiment. The coda‐wave attenuation is measured by means of Q within the single‐backscattering model and the single‐isotropic scattering model schemes. The frequency dependence of Q is analyzed using the power fit formulation Q ( f )= Q f α . The resulting Q , Q , and α are then used to study the seismic attenuation properties in western Mexico. We compare our results with the crustal structure by means of the surface geology, seismic activity, crustal thickness, and P ‐wave velocity patterns in the study area. There is a poor correlation of the attenuation parameters with such crustal features. However, an analysis of the variations of the P ‐wave velocity shows that the seismic attenuation parameters correlate to some extent with seismic velocity variations previously noted in the study area, where low attenuation and weak frequency dependence correlate with low‐velocity variation.