Preliminary analysis of emergency production and source parameters of the M 4.7 earthquake on September 18, 2024 in Feidong, Anhui

Abstract

At 20:08 on September 18, 2024, Beijing time, an earthquake of magnitude 4.7 occurred in Feidong, Anhui Province (31.98°N, 117.6°E). The China Earthquake Early Warning Network presented the first early warning results 8.9 ​s after the earthquake. The China Earthquake Networks Center (CENC) released the automatic rapid report results 163 ​s after the earthquake and the official rapid report results 8 ​min after the earthquake. At the same time, the CENC reported a series of emergency products, including source parameters, seismic tectonics, historical earthquakes, focal mechanism, instrument seismic intensity and predicted intensity. The results showed that the earthquake was located at the junction of the southern section of the Tanlu Fault and the Feizhong Fault, with aftershocks distributed in the NEE direction. The focal mechanism solution indicates that the earthquake is essentially a strike-slip event. The predicted intensity in the vicinity of the epicenter reaches up to VI, involving 23 towns that cover an area of about 1 359 ​km². Only one station near the epicenter shows a peak acceleration value greater than the fortification standard of the area, which may cause slight damage to some adjacent houses, consistent with the actual damage to buildings.