Lots of different ideas stay on whether the Dongbeiwang-Xiaotangshan Fault in the northwest of Beijing exists or how it displays and acts.This paper analyzes the present seismic prospecting data and drill logs from exploration of active faults in Beijing urban areas,and reaches conclusion that the Dongbeiwang-Xiaotangshan Fault does exist as a subsurface fault and it is 40km long,trending NNE.Divided by the Nankou-Sunhe Fault,we name its northeast segment as the Xiaotangshan Fault and the southwest segment as the Dongbeiwang Fault.The Xiaotangshan Fault is active in early Pleistocene but not in middle Pleistocene.The Dongbeiwang Fault is active in the end of mid-Pleistocene but not in late Pleistocene.

Identification of potential seismic zone follows the earthquake structure analogy and seismic activity repetition principles at present.Active fault segmentation is an important aspect and should be considered when identifying potential seismic zones.There are three different segmentation plans along Daqingshan piedmont fault,Inner Mongolia.This article compares and analyses the segmentations and then gets a new potential seismic zone identification plan along Daqingshan piedmont fault.Identification of potential seismic zone includes the range subdivision and the estimation on the maximum earthquake magnitude of potential seismic zones.This article sub-divides the ranges of potential seismic zones according to active fault segmentation plan along the Daqinshan piedmont fault proposed by Ran Yong-kang.Ordos Massif is surrounded by depression zones which have similar earthquake structures and historical earthquake records with magnitude over 8 expect the Hu-Bao depression zone.So,this paper compares Daqingshan piedmont fault with other depression zones around Ordos Massif,especially the Huashan piedmont fault,and gets the conclusion of the maximum earthquake magnitude of Daqingshan potential seismic zones.