Studies of VLF signal anomalies due to earthquake

We present evidences of anomalous VLF signals which we interpret to be precursors of seismic activities. These anomalies could be in VLF day lengths, or in D-layer preparation times, D-layer disappearance times, or, night time fluctuations. We made many case by case studies of major earthquakes and found that the anomalies occur 1-5 days before seismic events. We also made statistical analysis of several earthquakes together and came to same conclusions. Furthermore, we present results from several VLF receivers for a single earthquake and show that the result depends on the proximity of the propagation path to the epicenter.