Study on paleoearthquakes in Daqingshan piedmont fault, Inner Mongolia of China by using Holocene paleosols on the Paleo-alluvial-pluvial fans

This paper chooses Paleo-alluvial-pluvial fans in front of Daqingshan as the objects. We survey Holocene paleosols profiles on the Paleo-alluvial-pluvial fans in the three middle segments in front of the mountain, and carry out dating age. Then we compare paleosols ages on the Paleo-alluvial-pluvial fans to the paleoseismic events along the Daqingshan piedmont fault discovered by trench techniques. The contrast result demonstrates that paleosols ages on the Paleo-alluvial-pluvial fans have very close correspondence relations with paleoseismic events along the Daqingshan piedmont fault. So we think that paleosols ages on the Paleo-alluvial-pluvial fans can be used to reveal fault activity history. We have built the model of time relationship between paleosols ages on the Paleo-alluvial-pluvial fans and fault activity history by further step. This paper has made a great progress on the study of Holocene activities history of Daqingshan piedmont fault using the paleosols technique on the Paleo-alluvial-pluvial fans. The study of the palaseosols on the Paleo-alluvial-pluvial fans reveals that, over the past Holocene, 6 paleoseismic events had happened in Tumd Right Banner and Tumd Left Banner segments without exception, 2 paleoseismic events among which may bring about tearing level couplet breaking. 3 paleoseismic events had happened in Bikeqi segment. We have discovered another paleoseismic event on Tumd Right Banner segment and another 2 paleoseismic events on Tumd Left Banner segment, and restrained the ages of other paleoseismic events on further steps. The research has made the Holocene paleoseismic study on Daqingshan piedmont fault to tend to become entire and meticulous.