125 km E of Baiyin, China

A magnitude 7.9 earthquake — a major event — struck near 125 km E of Baiyin, China on December 16, 1920, at a shallow depth of about 15 km. An earthquake this size would have been felt strongly across the surrounding region; shallow earthquakes release their energy close to the surface, so they tend to cause the strongest shaking and the most damage. Shallow magnitude 7.9 events near a coastline can also pose a tsunami risk. Casualties, damage and the recovery depend on local building standards, population and distance from the epicentre — the news coverage, references and photos below capture what happened on the ground.