Hurley plots (Hurley, 1994) are simple but powerful graphical devices in which a cross-plot of cumulative dip magnitude, or rate of change of dip magnitude, versus a sample number or depth is produced. If the data has been acquired in regular intervals cumulative dips can be plotted against depth; whereas irregularly sampled dip data is plotted against sample number. Cumulative dip is plotted on the X-axis with sample number or depth on the Y-axis. These plots allow subtle, and not so subtle, changes in orientation data to be recognized and are readily produced within spreadsheets. We have found that Hurley plots are useful in situations where azimuths remain near constant through a succession but dip display a change, e.g. sections developing around salt masses or adjacent to growth faults.
See HURLEY, N. F. 1994. Recognition of faults, unconformities, and sequence boundaries using cumulative dip plots. Bulletin of the American Association of Petroleum Geologists, 78, 1173-1185.
See also azimuth vector plots.