关键词: 华南古地震, 灵山断裂, 灵山古地震, 灵山MS 6级地震, 地震重复间隔, 古地震强度

Abstract:  Presently paleoearthquake research in China mainly focuses on the strong seismotectonic provinces in the western and northern parts of the country. The South China Block (SCB) is located across the mediumstrong seismotectonic provinces where earthquakes of MS≥7.0 seldom occur. Traces of paleoearthquakes in SCB are hard to preserve due to high humidity, frequent rainfall and human activities in the region; as a result no detailed paleoearthquake studies are available. This research on the Lingshan paleoearthquakes, therefore, may fill the gap in the study of paleoearthquakes in South China. Based on our analysis of trenching, surface rupture and dating, it could be concluded that historically there were at least four earthquake events in the northern section of the Lingshan fault, and three of those were paleoearthquake events. They occurred around >36300, 25000, 13090 and 80 a B.P., respectively, following a trend of decreasing magnitude. The average time interval of the four earthquake events was about 12073 a and apparently longer compared with that of earthquakes occurred in the western and northern China, mainly due to relatively low tectonic activities in the Lingshan region.

Key words: South China paleoearthquake, Lingshan fault, Lingshan paleoearthquake, Lingshan MS 6 earthquake, earthquake recurrence interval, magnitude of paleoeartuquake