Project number: P07/02
Status Report (October 2003)
Project Title: Groundwater RAdon Monitoring through Overthrust Fault
Group Leader J. Wiegand: University of Essen (Germany)
Researchers J. Wiegand, S. Awissus : University of Essen (Germany)
Delivered access (filled by TARI administration): 64 man-days
Status report (filled by group leader):
The major aim of this experiment is to use 222Rn as a natural tracer to better define the transport processes in the groundwater. For that, two continuously measuring devices were installed and data was collected starting from February 2003 up to the present. The two devices are alpha-spectrometer monitoring the 222Rn concentration continuously and reliable in two different instrumental setups. One device (SARAD) runs in a closed gas-loop, therefore nothing can influence the trend of the 222Rn concentration, while the other device (Radim 4) runs in an open gas-loop, which offers the opportunity to gain also information about the variability of the 222Rn concentration dependent on the ground water flow rate.
The latter setup gives important information regarding to the fact, that 222Rn concentrations are monitored in a karst aquifer, which reacts fast upon changes in any other parameter like electrical conductivity, temperature and pH. In this way we are able to classify the reasons for these changes in a certain manner.
The results of the device with the open gas-loop during the last six months shows that there is a significant increase in the impulse rate during the whole March. This increase is produced by the snowmelt and shows the importance of a monitoring system, which is sensitive for flow rates. Following a normal seasonal trend, the increase should stop at a maximum level and transmute into a slowly decrease starting from April until the end of autumn. As expected the curve should stagnate at a minimum level during winter until the next snowmelt. The beginning of the expected decrease is in evidence, but starting from the end of April this decrease stops and the curve of impulses remains on a high constant level.
We assume high stress in the formation of the Gran Sasso massif as a reason for this remarkable effect, because starting from April/May we have an obvious increase in micro seismic activities in the vicinity of the Gran Sasso underground laboratories. To understand this effect, we need to search for correlations between all parameters, which are under consideration and clarify, if this effect will recur or vanish in the next year.
Future programs (filled by group leader):
During the measurements conducted in the frame of the TARI-project GRAMOF (Groundwater RAdon Monitoring through Overthrust Fault), hydrochemical ground water anomalies (especially radon) were observed, which need a new scientific approach and instrumental setup to be verified (see Status of the project).
To understand this process, we need to search for correlations between all parameters, which are under consideration and clarify, if this effect will recur or vanish during the next year. Therefore it is necessary to continue with the measurements in the oncoming year. Beside electrical conductivity, pH and temperature, the hydrostatic pressure is one of these essential parameters.
Therefore it is planed to make additional measurements in adjacent natural springs of the same aquifer to see the temporal propagation of ground water signals and anomalies. It is expected that seismic induced anomalies would occur more early in the centre of the Gran Sasso massif and then develop to the springs of the mountain flanks. Such measurements would give a better insight into the dynamic development of 222Rn anomalies.
Furthermore it is proposed to monitor not only the long lived 222Rn (3.8 d), but the short lived 220Rn (56 s) as well. Since such measurements are complicated due to the short half-life of 220Rn, and to the knowledge of the applications, a monitoring of 220Rn is a novelty. These measurements are planed for a testing phase of one week. Due to the differences in half-lives, 222Rn has a memory of up to 3 weeks, but 220Rn for only 5 minutes. The correlation of 222Rn and 220Rn concentrations can give important clues about groundwater radon transport. For that reason the experimental setup for 220Rn has to be improved and integrated in the existing measuring system for a longer period.
Publications planned or in preparation (filled by group leader):
Manuscripts are planned to be published in “Geophysical Research Letters”. It is expected that enough data is gathered to submit a manuscript at the end of the next year.
Group Leader J. Wiegand: University of Essen (Germany)
Researchers J. Wiegand, S. Awissus : University of Essen (Germany)
Delivered access (filled by TARI administration): 64 man-days
Status report (filled by group leader):
The major aim of this experiment is to use 222Rn as a natural tracer to better define the transport processes in the groundwater. For that, two continuously measuring devices were installed and data was collected starting from February 2003 up to the present. The two devices are alpha-spectrometer monitoring the 222Rn concentration continuously and reliable in two different instrumental setups. One device (SARAD) runs in a closed gas-loop, therefore nothing can influence the trend of the 222Rn concentration, while the other device (Radim 4) runs in an open gas-loop, which offers the opportunity to gain also information about the variability of the 222Rn concentration dependent on the ground water flow rate.
The latter setup gives important information regarding to the fact, that 222Rn concentrations are monitored in a karst aquifer, which reacts fast upon changes in any other parameter like electrical conductivity, temperature and pH. In this way we are able to classify the reasons for these changes in a certain manner.
The results of the device with the open gas-loop during the last six months shows that there is a significant increase in the impulse rate during the whole March. This increase is produced by the snowmelt and shows the importance of a monitoring system, which is sensitive for flow rates. Following a normal seasonal trend, the increase should stop at a maximum level and transmute into a slowly decrease starting from April until the end of autumn. As expected the curve should stagnate at a minimum level during winter until the next snowmelt. The beginning of the expected decrease is in evidence, but starting from the end of April this decrease stops and the curve of impulses remains on a high constant level.
We assume high stress in the formation of the Gran Sasso massif as a reason for this remarkable effect, because starting from April/May we have an obvious increase in micro seismic activities in the vicinity of the Gran Sasso underground laboratories. To understand this effect, we need to search for correlations between all parameters, which are under consideration and clarify, if this effect will recur or vanish in the next year.
Future programs (filled by group leader):
During the measurements conducted in the frame of the TARI-project GRAMOF (Groundwater RAdon Monitoring through Overthrust Fault), hydrochemical ground water anomalies (especially radon) were observed, which need a new scientific approach and instrumental setup to be verified (see Status of the project).
To understand this process, we need to search for correlations between all parameters, which are under consideration and clarify, if this effect will recur or vanish during the next year. Therefore it is necessary to continue with the measurements in the oncoming year. Beside electrical conductivity, pH and temperature, the hydrostatic pressure is one of these essential parameters.
Therefore it is planed to make additional measurements in adjacent natural springs of the same aquifer to see the temporal propagation of ground water signals and anomalies. It is expected that seismic induced anomalies would occur more early in the centre of the Gran Sasso massif and then develop to the springs of the mountain flanks. Such measurements would give a better insight into the dynamic development of 222Rn anomalies.
Furthermore it is proposed to monitor not only the long lived 222Rn (3.8 d), but the short lived 220Rn (56 s) as well. Since such measurements are complicated due to the short half-life of 220Rn, and to the knowledge of the applications, a monitoring of 220Rn is a novelty. These measurements are planed for a testing phase of one week. Due to the differences in half-lives, 222Rn has a memory of up to 3 weeks, but 220Rn for only 5 minutes. The correlation of 222Rn and 220Rn concentrations can give important clues about groundwater radon transport. For that reason the experimental setup for 220Rn has to be improved and integrated in the existing measuring system for a longer period.
Publications planned or in preparation (filled by group leader):
Manuscripts are planned to be published in “Geophysical Research Letters”. It is expected that enough data is gathered to submit a manuscript at the end of the next year.