[1]CUI Yueju,SUN Fengxia,DU Jianguo.Methods for Identification of Seismic Geochemical Precursors and Source Partitioning of Hot Spring Fluids in Eastern Chinese Mainland[J].Journal of Seismological Research,2022,45(02):199-216.[doi:10.20015/j.cnki.ISSN1000-0666.2022.0051
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Methods for Identification of Seismic Geochemical Precursors and Source Partitioning of Hot Spring Fluids in Eastern Chinese Mainland
Journal of Seismological Research[ISSN 1000-0666/CN 53-1062/P] Volume:
45
Number of periods:
2022 02
Page number:
199-216
Column:
Public date:
2022-05-20
- Title:
- Methods for Identification of Seismic Geochemical Precursors and Source Partitioning of Hot Spring Fluids in Eastern Chinese Mainland
- Keywords:
- hot spring fluids; geochemistry; source partitioning; earthquake precursor; identifying method
- CLC:
- P315.724
- DOI:
- 10.20015/j.cnki.ISSN1000-0666.2022.0051
- Abstract:
- The origins of water and gas in hot springs in eastern China's mainland were discussed by means of source partitioning,and the models of assessing percentages of deep fluids and mantle-derived helium in hot spring fluids and methods of identifying seismic geochemical anomalies were proposed by statistically analyzing thousands of geochemical data of meteoritic water,hot spring fluids,experimental rock-water reactions and gaseous isotope compositions in mantle-derived xenoliths from the literatures. δ18O and δD data of spring waters indicate H2O of springs are predominantly originated from meteoric water,while ions and heat energy transported by small amount(<1%)of deep thermal fluids must be emphasized. The statistical results of data of meteoric water and soluble ions of air particles indicated that sea salt contribution to the hot spring water was usually negligible. The models δ18O-δD and Na+-Cl- for source identification were proposed based on statistical analysis of plenty of chemical data of meteoric water,soluble ions of air particles and ion concentrations of deep thermal fluids and hot spring waters. The mean value or peak value of more than 380 3He/4He ratios and δ13CCO2 values of mantle xenoliths in Cenozoic basalts in eastern China can be considered as the isotopic compositions of He and CO2 in the local upper mantle. The value of mantle end-member to estimate percentage of mantle-derived He in hot spring gases by using the two end-member model,therefore,average(2.1RA)of 3He/4He of Hannuoba xenoliths should be employed in the orogenic belts in the west of the Nenjiang-Zijingguan fault,while higher peak value(7RA)of 3He/4He of mantle xenoliths in eastern China should be used in the continental rift valley in the east of the fault,which favors reasonable assessment of heat energy supplied from the mantle to the hot spring system,geothermal fields and earthquake generation. The seismic geochemical anomalies could be identified in the time series of geochemically monitoring data of hot springs after ion contributions of sea salt,atmospheric and artificial sources to the spring waters were eliminated by using the proposed source partitioning models. The anomalies of multiple geochemical indicators occurred simultaneously or in short period in an area of 500 km radius could be considered as earthquake precursors. Additionally,the monitoring data from other disciplines should be combined to identify earthquake precursors and predict earthquake using geochemical data.
- References:
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Last Update:
2022-05-20