Studes of geophysical field features before the baotou earthquake (Ms6.4)

In this paper, by studying precursory data of large range before Baotou earthquake (Ms6.4), the Authors suggested that anomalies group of precursor field may appear with different fea-Tures before a strong earthquake in different areas around the epicenter, The main char-Acter of the near field (△≤100 km) is a tendency anomaly with relatively long time scale;the main character of the middle-far field (100 km < △≤200 km)showed both tendency and sudden anomalies, but the distant field, generally speaking, showed no anomalies, only showed short term and imminent prexursors of the earthquake.