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The chemical components, He, Ne, and C isotropic ratios of gas samples collected thrice from 32 hot springs in western Sichuan Province, southwestern China in June and October 2008 and June 2009 were investigated in order to discuss the relationship between hot spring gas geochemistry and the Wenchuan Ms 8.0 earthquake. The data showed that the 3 He/ 4 He and C 13CO2 d values in spring gases in the Longmenshan fault (LMSF), Xianshuihe fault (XSHF), and Minjiang fault (MJF) zones increased obviously after the great earthquake. It was estimated that up to 62% of mantle helium contributed to the spring gas in the Kangding region based on the maximum 3 He/ 4 He (7.42 × 10 -6 ) in June 2008. Over time the mantle derived fluid contribution to the hot springs gradually decreased, but the crustal gas components: CO 2 and CH 4 derived from organic matter and radiogenic He increased. The gas geochemical data suggested that more mantle fluids migrated into the crust in western Sichuan Province after the Wenchuan Ms 8.0 earthquake.

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Abstract. In total, 29 continuous Global Positioning System (GPS) time series data together with data from Gravity Recovery and Climate Experiment (GRACE) are analysed to determine the seasonal displacements of surface loadings in the North China Plain (NCP). Results show significant seasonal variations and a strong correlation between GPS and GRACE results in the vertical displacement component; the average correlation and weighted root-meansquares (WRMS) reduction between GPS and GRACE are 75.6 and 28.9 % respectively, when atmospheric and nontidal ocean effects were removed, but the annual peak-topeak amplitude of GPS (1.2-6.3 mm) is greater than the data (1.0-2.2 mm) derived from GRACE. We also calculate the trend rate as well as the seasonal signal caused by the mass load change from GRACE data; the rate of GRACEderived terrestrial water storage (TWS) loss (after multiplying by the scaling factor) in the NCP was 3.39 cm yr −1 (equivalent to 12.42 km 3 yr −1 ) from 2003 to 2009. For a 10-year time span (2003 to 2012), the rate loss of TWS was 2.57 cm yr −1 (equivalent to 9.41 km 3 yr −1 ), which is consistent with the groundwater storage (GWS) depletion rate (the rate losses of GWS were 2.49 and 2.72 cm yr −1 during 2003-2009 and 2003-2012 respectively) estimated from GRACE-derived results after removing simulated soil moisture (SM) data from the Global Land Data Assimilation System (GLDAS)/Noah model. We also found that GRACEderived GWS changes are in disagreement with the groundwater level changes from observations of shallow aquifers from 2003 to 2009, especially between 2010 and 2013. Although the shallow groundwater can be recharged from the annual climate-driven rainfall, the important facts indicate that GWS depletion is more serious in deep aquifers. The GRACE-derived result shows an overall uplift in the whole region at the 0.37-0.95 mm yr −1 level from 2004 to 2009, but the rate of change direction is inconsistent in different GPS stations at the −0.40-0.51 mm yr −1 level from 2010 to 2013. Then we removed the vertical rates, which are induced by TWS from GPS-derived data, to obtain the corrected vertical velocities caused by tectonic movement and human activities. The results show that there are uplift areas and subsidence areas in NCP. Almost the whole central and eastern region of NCP suffers serious ground subsidence caused by the anthropogenic-induced groundwater exploitation in the deep confined aquifers. In addition, the slight ground uplifts in the western region of NCP are mainly controlled by tectonic movement (e.g. Moho uplifting or mantle upwelling).

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