According to China Earthquake Networks Center, an M3.6 earthquake occurred near Miaofengshan Town, Mentougou District, Beijing (40.04°N, 115.95°E) at 00:54 on May 26, with a focal depth of 18 kilometers. As measured by the Beijing Strong Motion Network, the maximum seismic intensity reached Grade III. Some residents around the epicenter felt shaking, which lasted only a short time.
No historical records of earthquakes above magnitude 5 exist in Mentougou. The largest recorded earthquake was the M4.2 event on November 21, 1985, located 22 km from the epicenter of this earthquake. The nearest fault to both earthquakes is the Nankou Piedmont Fault, a normal fault. Calculations by the China Earthquake Networks Center and Beijing Earthquake Administration show that the May 26 M3.6 earthquake occurred 11 km away from the Nankou Piedmont Fault, at a relatively long distance. Its rupture mechanism is strike-slip rupture, inconsistent with the activity characteristics of the Nankou Piedmont Fault, indicating weak correlation with the fault. This earthquake was not triggered by large-scale fault movement.
Statistics from the Beijing Seismic Network show that no earthquakes above magnitude 0 were recorded within a 20 km radius of the epicenter in the month preceding the M3.6 event. Historical seismic statistics reveal that isolated earthquake sequences and mainshock-aftershock sequences predominate in this area. Records from the Beijing Seismic Network indicate that this earthquake produced few low-magnitude aftershocks, with no aftershocks above magnitude 0 detected so far. The probability of a larger earthquake in the coming days is low.
Small earthquakes have been relatively active in the Beijing region since 1970. On average, one M4 earthquake occurs every five years, and two earthquakes above M3 occur every three years. There has been a 24-year quiescence of M4 earthquakes in Beijing following the Shunyi M4.0 earthquake in 1996; there was also a 17-year quiet period for M3+ earthquakes from 2002 to 2018, far below the average seismic activity level. The Mentougou M3.6 earthquake represents a normal fluctuation of seismic activity in the Beijing area.
(Source: Beijing Earthquake Administration)