The IP measurement has a low background value above which IP data can be called anomalous, yielding a more definitive interpretation than other geophysical methods. For resolving IP sources, broad band IP data should be collected. The most cost effective way to obtain enough spectral IP (SIP) information routinely is by time-domain SIP measurement. Although the Cole-Cole parameters (chargeability M, time const T and exponent c) have been found to be very useful in resolving SIP sources in a frequency-domain, these parameters can also be determined through computer matching of the time-domain SIP data by the best fit in a family of pre-calculated Cole-Cole curves.

Time-domain SIP has first been applied to the southern Chinkushih area, northern Taiwan, for the resolution of SIP sources. Based on the time domain SIP analysis, possible concealed porphyry gold/copper deposits, or breccia pipes in the margin of the Wutanshan intrusion were located.