18a respectively thus five distinct peaks impacts or hits will be detected by circuitry 25 in fig6 spikes 48 50 52 54 and 56 correspond to contact between asperity 32 and sensors 18e 18d 18c 18b and 18a respectively using the relationship shown in equation 1 height h a of each asperity can be determined from the number of hits n the known sensor lamination pitch l p the minimum fly height h mfh of abs 14 and the pitch u03b8 p of the slider in addition to providing the ability to accurately determine the heights of asperities on the surface of the discs the multiple mr sensors of head 10 of the present invention increases the probability that thermal asperities will be detected from contact with broad shallow defects in conventional thermal asperity detecting heads having only a single sensor contact between an asperity and the abs can temporarily alter the flight of the head such that the mr sensor asperity contact does not produce a thermal asperity in the read out signal as illustrated progressively in fig7 a and 7b the initial contact between abs 14 and asperity 34 can alter the fly height and pitch angle u03b8 p of the head temporarily as shown progressively in fig7 c and 7d because of the altered flight of the head mr sensor 18c makes contact with asperity 34 but mr sensors 18a and 18b do not thus by including multiple mr sensors spaced apart on abs 14 of the slider body the likelihood that at least one of the mr sensors will.