A comparative analysis of the quality factor Q for the regions of Guerrero and Oaxaca, México

Abstract

Estimates of the quality factor Q. of S waves reported for the regions of Oaxaca and Guerrero, Mexico show that the attenuation in Oaxaca is 3.7 to 5.0 times greater than that in Guerrero for the frequency band from 1 to 30 Hz. This important difference in attenuation of these neighboring regions cannot be completely explained by petrological difference. When the observed values of Q. for Oaxaca and Guerrero are compared with the age of the rocks and the heat flow, it turns out that the attenuation in Oaxaca is greater than expected relative to that in Guerrero. This suggest that the most likely mechanism to explain the observed differences in Q. may be related to the state of stress prevailing when Q. was measured. The high values of Q. estimated for Guerrero can be the result of a Jess fractured crust and tectonic stress accumulated in this region.