A [[well log]] of the [[acoustic]] properties of rock made by a contact [[pad]] device which presses the acoustic [[transducer|transducers]] against the [[formation]] wall. The span of the acoustic [[receiver|receivers]] is 6.0 inches, producing a transit time [[curve]] with much sharper interface resolution which aids recognition of thin, interbedded strata and finding of lowangle fractures. The Sidewall Acoustic Log (SWA) is a Dresser Atlas trademark