Radon concentration anomaly characteristics in the North–South seismic belt before strong earthquake

Seismic underground fluids play an important role in earthquake prediction studies and tracking. Nearly 30 years of radon concentration monitoring data at 42 observation sites the North–South seismic belt (22°-35° N, 100°-110° E) were collected from National Earthquake Data Center China Networks Center. The possible precursor anomalies observed before several strong earthquakes investigated their spatial distribution, evolution, variation characteristics analyzed. results showed that high, morphological are relatively complex. anomaly mainly shows turning point or accelerating change trend background change; longer durations tend to be concentrated around epicenters. number points with was positively correlated proximity epicenter; measurement closest epicenter exhibited earlier anomalies. research has practical significance scientific value for understanding relationship between earthquake.