1. Soil Radon Flux in Hydrothermal Area of the Tatun Volcano Group, N. Taiwan and its Monitoring Results Tsanyao Frank Yang 1, C.-C. Fu 1, H.Y. Wen 1, W.L. Hong 1, S.J. Lin 2 and V. Walia 2 1.Department of Geosciences, National Taiwan University 2. National Center for Research on Earthquake Engineering, NARL, Taiwan

6. Soil CO 2 Station in Italy

7. Why CO 2 & Rn ??  CO 2 is, after water vapor, the most abundant gas phase dissolved into magma.  CO 2 is one of the first gases to be exsolved and released from an ascending magma.  Increase in volcanic CO 2 emission can be used as early indicators of magma up-rise.  Radon is trace gas and also sensitive to the magma activity.  Both CO 2 and Radon sensors are commercially available ==> un-expensive and easy for continuously monitoring in corrosive environment !!

8. METHOD CO 2 flux measurement Soil gas sampling for gas comp and isotopic analysis by MS. In situ soil Rn analysis CO 2 flux measurement again

9. Testing sites @ SYK

10. S7S7 S1 0 S8S8 S9S9 S2 S5 S1 S6 S4 S3 Testing sites @ SYK

11. Site 5 CO2 FLUX (ppm/sec)T ( ℃ )Radon BEFORE5.825.5Balance value6102.3 Bq/m3 AFTER9861Temperature32 ℃ Humidity85 %

12. Site 6 CO2 FLUX (ppm/sec)T ( ℃ )Radon BEFORE3.83.1Balance value4064.1 Bq/m3 AFTER207.391Temperature29 ℃ Humidity87 %

13. Site 7 1426.7 Bq/m3

14. Summary of survey results locationRn (Bq/m 3 ) CO 2 flux (ppm/sec) 3 He/ 4 He (Ra) CO 2 conc (v %) H 2 S+SO 2 conc (v%) Site 13420.61.095.440.10 Site 232593683.7679.012.58 Site 34980.51.035.590.14 Site 4128424.54.5685.781.67 Site 5610298.03.6478.458.25 Site 640642074.6580.685.23 Site 714272.11.041.580.16 Site 833393.84.7185.810.22 Site 91584629264.8087.107.65 Site 10900.41.170.220.20 Higher CO 2 flux => higher radon flux => higher magma signals

15. Configuration of Monitoring Station @SYK Equipped with: Rn & CO 2 sensors which protected with plastic box and epoxy

16. Station @SYK

18. CO 2 Result

19. CO 2 & Rn Result

20. CONCLUSIONS  The soil gases show significant magma signals (high 3 He/ 4 He ratios, CO 2 flux, and total sulfurs) at SYK hydrothermal area.  The first monitoring station was successfully setup at SYK hydrothermal area in Taiwan. It is equipped with CO 2 and Rn sensors, which are protected with plastic box and epoxy, and then can be used for long term monitoring under corrosive environments.  Both CO 2 flux and radon concentrations show significant variations. They are correlated well with other magmatic proxy ( 3 He/ 4 He ratios and total sulfurs etc.) and can be used for further monitoring on the local magma activity.