A unified alteration index (UAI) for mafic rocks

The geomechanical properties of diabase in the ophiolitic melange and basal t in the Lower and Middle Eocene volcanics of Ankara, Turkey, were determin ed as part of an investigation of potential dam sites, A classification is proposed based on a concept called the "unified alteration index (UAI)," wh ich expresses a percentage decrease in uniaxial strength and compressional wave velocity of the mafic rocks determined in the laboratory, The UAI clas sification consists of five groups-unaltered, slightly, moderately, highly, and extremely altered-for this proposed modified classification system, A statistical analysis was used in examining the relationships between the UA I and geomechanical properties of the mafic rocks, and revealed that the UA I = exp (-0.0495 - 0.001 sigma(c)) (r(2) = 0.64) and UAI = 1.0058 - 7.663e - 5C(p) - 8.227e-9C(p)(2) (r(2) = 0.93).