We present a characterization of large amplitude, short-timescale
geomagnetic disturbances that we refer to as transient induced current
(TIC) events. TIC events are defined as one or more short-timescale
(< 60 seconds) dB/dt signature with magnitude ≥ 6 nT/s.
We identified 40 TIC events that occurred at six stations of the
Magnetometer Array for Cusp and Cleft Studies throughout 2015 and we
demonstrate the existence of large-amplitude dB/dt with timescale
less than 10 seconds in nine of the events. The association of these
events to sudden commencements is weaker than expected, rather the
events are more likely to occur in relation to substorm onsets. However,
15% of TIC events show no direct association to geomagnetic storms,
substorms or nighttime magnetic impulse events. Our findings suggest
that the TICs have different properties than typical geomagnetically
induced currents and may be hazardous to conductive components of the
Internet of Things network.