Electromagnetic anomalies

Departures from an expected or established baseline in measured electric fields, magnetic fields, electromagnetic emissions, geomagnetic conditions, radio-frequency propagation, or related ionospheric signals. Within WIVVI, this concept includes ground-based and satellite-recorded anomalies across frequency ranges such as ULF, ELF, and VLF. An electromagnetic anomaly may result from natural environmental variation, solar or geomagnetic activity, lightning, human technology, instrument effects, or other causes; its detection alone does not establish an earthquake precursor, predictive signal, or causal connection with seismic activity.