Research on the common characteristics of Yangbi earthquake with M5.1 in 2017 and M6.4 in 2021

There are some common characteristics of anomalies in the seismicity and subsurface fluid observation materials before the M5.1 earthquake on March 27, 2017, and the M6.4 earthquake on May 21, 2021, in Yangbi, Yunnan. The common characteristics of anomalies in seismicity are as follows: an anomaly in M≥5.0 Yunnan earthquake quiescence; an anomaly in M4.0～4.9 Yunnan earthquake quiescence; the low-frequency activity of M≥3.0 Yunnan earthquakes changed to an enhancing trend; M≥4 earthquakes showed a stripping distribution in western Yunnan; M4 double earthquakes occurred before Yangbi M5.1 and M6.4 earthquakes. The water temperature, water mercury, solid carbon dioxide, and water radon in the subsurface fluid observation materials have the common characteristics of short- and medium-term anomalies, among which the water mercury in Baoshan, solid carbon dioxide in Xiaguan and Eryuan, and water radon in Xiaguan, Longling and Tengchong have the common characteristics of short- and medium-term synchronous anomalies.