Abstract: Gas is the sensitive component for identifying distribution and activity of tectonic zones. In this paper, the variogram method was employed to calculate the spatial high resolution data of gas geochemistry in the Tangshan fault zones and to analyze the quantitative relationship between the activities of fault zones and the concentration of fault zone gas. The results indicate that the structural characteristic of the fault zones is the major factor influencing the spatial distribution of fault zone gas among gaseous resources, meteorological-hydrological conditions and carrier gas etc., high-dip faults encompass the main anomalous high gas distribution with a form of narrow ribbon on the surface, anomalous annular connection areas are formed in the intersection area of fault zones. Along strike direction, fault zone gas with anomalous high concentration is congruent with tectonic lines. By means of the variogram, the correlation domain between gas concentration and tectonics is determined, thus the tectonic sensitive gas is determined in each segment of Tangshan faults, around fault zones, and the key monitoring area of fault activities can be designated. The Kriging interpolation plots of fault zone gas illustrate that the Luanxian—Laoting Fault is the most active fault, the Tangshan Fault is second, the Jiyunhe Fault is relatively stable. In the converged area, fault zone gas shows more sharply anomalous high concentrations.

Key words: Fault zone gas, Geochemistry, Variogram, Spatial distribution, Correlation