The analysis and design of machine foundation requires more attention since it rninvolves both the static loads and the dynamic loads caused by the machine. The rnresponse of such foundation under machine induced vibration depends on several rnparameters such as the shape and size of the foundation, depth of embedment,rnstatic load, dynamic excitation frequency, and other geotechnical parameters. rn The main objective of this study focuses on the sensitivity and comparativernstudy of coupled horizontal and rocking vibration of block machine foundation byrnapplying a direct approach which directly considers the combined effect of forcernand moment without simplifications. This direct approach is compared with a superpositionrnmethodrnwhichrnusesrnsimplernsuperpositionrnofrnthernseparaternactionrnofrnthernrnforcernandrnthernmoment.rnInrnbothrnmethodsrnimpedancernfunctionsrnarernutilizedrnbyrnmakingrnusernofrncompiledrnclosedrnformrnexpressionsrnandrndimensionlessrngraphsrnforrnthernpurposernrnof determining frequency dependent dynamic stiffness and dashpot coefficients.rnrn rnrnTheoreticalrnresultsrnarernalsornvalidatedrnbyrncomparingrnresultsrnfromrnexistingrnexperimentalrninvestigationsrnonrnfieldrntest.rnTherncomparisonrnshowedrnanrnencouragingrnrnagreementrninrntherncasernofrnsurfacernfoundationrnforrnpredictionrnofrnnaturalrnfrequency.rnrnFurthermore,rnarnsensitivityrnstudyrnhasrnbeenrnconductedrnonrnreciprocatingrncompressorsrnrnbasedrnonrntherndynamicrnresponsernofrnsurfacernandrnembeddedrnblockrnfoundationsrnforrndifferentrnaspectrnratiornunderrncoupledrnmodernofrnvibrationrnforrndifferentrnembedmentrnratiornrnforrnclay,rngravelrnandrnsand.rnThernresultsrnindicaternthatrnasrnthernembedmentrndepthrnincreases,rnthernresonantrnamplituderndecreasesrnandrnresonantrnfrequencyrnincreases.rnInrnrntherncasernofrntherndampedrnnaturalrnfrequencyrnwhenrnthernaspectrnratiornincreasesrnhorizontalrnandrnangularrnamplitudernincreasernandrndampingrnratiorndecreases.rnOnrnthernotherrnrnhand,rninrntherncasernofrnthernundampedrnnaturalrnfrequencyrnhorizontalrnamplitude,rnangularrnamplitudernandrnfrequencyrnratiorndecrease.