"Major" in this case is an exaggeration. 5.4 mb isn't major. There is a school of thought that if electrical precursors exist, they should only exist for large earthquakes where large rock volumes are involved. This may be untenable. I'm trying to trace reports of a spectacular and thoroughly anomalous fireball seen in the sky over the epicentral area of last Sunday's quake in Leicestershire, 20 hours before the event. There were numerous observers, and the descriptions agree in detail. The earthquake was 4.1 ML.