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Liu L.,Seismological Bureau of Hebei Province | Gong M.,Seismological Bureau of Hebei Province | Hu B.,Seismological Bureau of Hebei Province | Zeng X.-F.,Hefei University of Technology | Luo Y.,Institute of Earthquake Science

We present the surface wave dispersion results of the application of the ambient noise method to broad-band data recorded at 83 stations from digital seismic networks of the Hebei and surrounding areas. Firstly we used the multiple-filter analysis method to extract surface wave group velocity dispersion curves from inter-station paths at periods from 5 to 50s. Then using linear inversion method to obtain shear wave velocity distribution. The results of group and shear wave velocity distribution maps generally demonstrate good correlations with surface geological and tectonic features. The results of the group velocity tomography show that at short periods (8~20s), basin areas are clearly resolved with low group velocity due to its thick sedimentary layer, and the uplift areas show relative higher group velocity distribution. With the increase of period (> 20s) the group velocity distribution changed, and velocity gap between the basin and uplift areas had reduced after the 30s period, due to the thickness of the Earth's crust, and beneath the middle-lower the shear wave velocity increase with depth. Our results also show that in this study the dominated noise sources come from the north-west. Source

Karakostas V.,Aristotle University of Thessaloniki | Papadimitriou E.,Aristotle University of Thessaloniki | Jin X.,Seismological Bureau of Hebei Province | Liu Z.,Seismological Bureau of Hebei Province | And 2 more authors.
Journal of Asian Earth Sciences

Northeast China, a densely populated area, is affected by intense seismic activity, which includes large events that caused extensive disaster and tremendous loss of life. For contributing to the continuous efforts for seismic hazard assessment, the earthquake potential from the active faults near the cities of Zhangjiakou and Langfang in Hebei Province is examined. We estimate the effect of the coseismic stress changes of strong (M≥. 5.0) earthquakes on the major regional active faults, and mapped Coulomb stress change onto these target faults. More importantly our calculations reveal that positive stress changes caused by the largest events of the 1976 Tangshan sequence make the Xiadian and part of Daxing fault, thus considered the most likely sites of the next strong earthquake in the study area. The accumulated static stress changes that reached a value of up to 0.4. bar onto these faults, were subsequently incorporated in earthquake probability estimates for the next 30. years. © 2013 Elsevier Ltd. Source

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