Field of technology

The invention relates to the method and equipment for the monitoring of changes in the earth's lithosphere and atmosphere, namely for prediction of earthquakes.

Present state of art

In spite of the progress made in the last decade in the research of the dynamism of the earth's body, prediction of earthquakes is still a very difficult matter. It is possible to determine the probability of tremors in certain area; it is also possible to determine the year in which expected tremors are likely to occur, thoug precise prediction of the hour or the day resists all efforts.

So far predictions of earthquakes have been based chiefly on analyses of data from past earthquakes, which allow compiling maps of seismic hazards, in which probable earthquake events are charted for defined areas. Three facts are taken into account in the determination of the degree of hazard, i.e. knowledge of historic earthquakes, knowledge of the geological constitution of the area, and knowledge of the situation in terms of geological engineering. The resulting data are plotted in maps, which show either the expected intensity of tremors in the earthquake zones, or probable acceleration of the earth's surface. In order to predict earthquakes, so- called foreshocks, i.e. minor shocks that occur prior the main movements, are also monitored.

Beside predictions based on analysis of known historic earthquakes, other predictions are based on changes of physical fields of the earth, especially electric, magnetic and gravity fields, monitoring of chemical changes of ground waters and gases, or changes of elevation of the earth's surface.

Behaviour of animals is also studied for the prediction of earthquakes, as animals are sensitive to barometric and acoustic phenomena imperceptible to humans, which precede an imminent earthquake.

It has also been found that unusual atmospheric phenomena precede great earthquakes. This is why monitoring stations are installed in earthquake zones, and data describing events in the upper layer of the atmosphere and in the ionosphere during earthquakes are collected and transmitted via satellite.

Attention has focused recently on the monitoring of seismic waves before, during and after earthquakes. It has been found that the velocity of seismic waves differs by the degree of stress in consequence to the opening and closing of cracks in the earth's crust. The seismic signal transmitted from fault zones between the lithospheric plates precedes the earthquake by several tens of minutes. Mounting stress in the lithosphere, which heralds an imminent earthquake, is detected by measuring the changes of the velocity of seismic waves. The lithosphere is the solid envelope of the earth, consisting of the crust and the uppermost strata of the mantle. The lithosphere is not a compact envelope; it is split to large bodies known as the lithospheric plates, which "float" and collide with each other on top of the plastic layer of the earth's mantle, the asthenosphere.

Existing studies include those focusing on radon as a gas whose occurrence may precede earthquakes (T rique et al, 1999; Igarashi et al, 1995, 1993; Igarashi and Wakita, 1990; Wakita et. al, 1991; Liu et al, 1985; Hauksson and Goddard, 1981; Noguchi and Wakita, 1977; Shapiro et al, 1981; Teng, 1980; Wakita et al.,1980) However, no reliable earthquake prediction based on the content of radon in soil or in air has been published so far. An increase of radon concentration prior to the earthquake proper (typically days to weeks) has been detected in most cases, though in some cases, on the contrary, a drop of radon concentration was detected in some cases.

; Monitoring of instantaneous bulk radon and thoron activity in soil gas is used as part of the monitoring of volcanic activity, e.g. in the Etna area (e.g. S.

Giammanco, Measurements of220Rn and 222Rn and C02 emissions in soil and fumarole gases on Mt. Etna volcano (Italy): Implications for gas transport and shallow ground fracture, 2007).

)

The results of the above monitoring processes do not yield adequate data for precise and reliable prediction of earthquakes. No detailed physical description of relevant dynamic processes in the earth's crust, focusing on earthquake prediction, has been published so far.

General prediction of earthquakes is still hindered by the diversity of conditions preceding the earthquake. Each fault zone has a totally different geological constitution and different history. The search is still going on for the set of conditions which evidently precede the earthquake.

Document WO 2014/049408 describes the measuring equipment for the prediction and localization of earthquake epicentres by measuring anomalies of radon content in soil, which includes two interconnected measuring modules, of which one is installed in the soil, the other on the surface. The measured values of bulk radon activity are transferred to the server, where data from a number of independent measurement points are compared and processed using an algorithm that compares measured values from a network of ground and surface measurement points to the mean value of bulk radon activity, with the aim of predicting earthquakes and volcanic eruptions as well as calculating the epicentre and magnitude. The algorithm of data processing is not described in detail. The above measuring equipment only monitors and evaluates the time course of radon concentration in soil and on the surface, which does not seem adequate for reliable prediction of the time and place of a possible earthquake.

The object of the invention is to find a new method of monitoring changes in the earth's lithosphere and atmosphere to enable an easier, more reliable and longer- term prediction of earthquakes than what today's state of technology allows.

Substance of the invention

The inadequacies of the present state of art are significantly eliminated, and the object of the invention is achieved by the method of monitoring changes in the earth's lithosphere and atmosphere according to Claim 1. Efficient executions of the method based on the invention are described in the dependent claims 2 to 4.

The inadequacies of the present state of art are significantly eliminated, and the object of the invention is achieved by the equipment formonitoring of changes in the earth's lithosphere and atmosphere according to independent Claim 5.

Efficient executions of the equipment based on the invention are described in dependent Claims 6 to 12.

The method and equipment for the monitoring of changes in the earth's lithosphere and atmosphere are based on the understanding of the phenomena preceding the earthquake and its course in time. The method and equipment for the monitoring of changes in the earth's lithosphere and atmosphere are based on the understanding that changes preceding earthquakes are manifested in more natural products and more physical quantities than just anomalies of bulk radon activity in soil and on its surface.

The method and equipment for the monitoring of changes in the earth's lithosphere and atmosphere as proposed by the invention are furthermore based on the fact that great stress occurs in the fault between lithospheric plates prior to an earthquake; the stress causes changes in the concentration of soil gases including radon and increased escape thereof; the changes thus provoked depend on the magnitude of the earthquake, its location and time. Radioactivity from soil gases, namely radon and its short-time decay products, ionizes air on a large scale and causes

condensation of water vapours. Temperature and infrared radiation also increase significantly due to this process.

The method and equipment for the monitoring of changes in the earth's lithosphere and atmosphere as proposed by the invention are based on systematic continuous monitoring of important variables and analysis of their changes in time, including the velocity of their increase and decrease, systemic shift of time sequences, and further, more detailed analysis of the sequences using advanced methods of statistical data processing.

One of the seismic side effects before and during an earthquake is a change of the pressure of soil gases, which, geologically speaking, must inevitably contain radon and thoron due to their parent elements uranium and thorium, contained in the earth's crust. Another assumed side effect is the formation of cracks and fractures in the crust, including minor cracks. A change of pressure (increase) is manifested by an increased escape of radon and thoron at "favourable" points, and on the contrary by a reduced occurrence at other points, possibly in relation to the formation of cracks and fractures. In consequence to an increased discharge of radon and thoron, their short-time decay products (DP) also form over time, namely after diffusion of the gases in question to the atmosphere, because the DP formed in soil/rock are captured there.

An increased occurrence namely of radon, trailed in the atmosphere by an increase of their DP, is also manifested by increased count of ions at the site of discharge. Due to the dilution and spontaneous radioactive decay in the atmosphere further away from the site of the discharge (eruption), the original bulk radon activity (BRA), the initial ion count, and bulk activities (BA) of individual DP gradually decrease, and, last but not least, the initial ratio (BA) of individual DP also changes significantly, as is easy to measure especially for radon, i.e. the ratio (BA) of radio nuclides ²¹⁸ Po: ²¹⁴ Pb: ²¹⁴ Bi. What changes principally is the most easily measurable ratio (BA) of DP of radon and BRA, known in literature as the coefficient of imbalance F (see Note 1 below). The trajectory of diffusion of atmospheric radon and DP of radon and thoron is influenced namely by the speed and trend of wind, which are to be measured in the station or network of stations together with radon and DP.

Bulk radon activity in soil is understood as radon activity in a unit of volume (1m ³ ) of air collected from pores in soil. Areal velocity of radon exhalation from soil represents the activity of radon diffusing from a unit of area (soil in this case) into the atmosphere per unit of time. The two quantities may or may not be independent of one another and their ratio is another monitored parameter in the prediction of earthquake phenomena.

Whilst the physical half-time of decay of radon is ca. 3.8 days and the half-time of its longest DP ²¹⁴ Pb is ca. 27 minutes, the half-time of decay of thoron is short (ca. 1 min.), but the half-time of its longest DP ²¹⁴ Pb is as much as ca. 11 hours. This implies that beside the detection of radon and its DP, detection of DP of thoron could be quite important at points of expected discharges where geology suggests a content of thorium in soil. Simultaneous measurement of radon and thoron including their DP with totally different half-times therefore allows for sensitive monitoring of different velocities of changes of physical processes. Given the aforesaid longer physical half-time and with regard to the expected speed of air masses (metres to tens of metres per second) on the global scale, the detection of radon and its DP are more important.

The following factors are seen as key elements for the prediction of earthquakes using detection of radon and its DP according to the invention:

a) appropriate location of the station or network of stations in the area of identified geological faults;

b) long-term measurement of the "background", namely of radon and its DP, correlated with the stability of the atmosphere in view of its vertical mixing; c) long-term measurement of atmospheric background of radon and its DP, as well as its variations in soil and water, correlated to selected soil and water parameters (water temperature, soil moisture and temperature at selected depth profiles) including exhalation of radon from soil.

The most frequent measurement is conducted in the top strata of soils (non- cohesive rock environment). Generally speaking, monitoring can be conducted also in the bedrock, confined or unconfined aquifers, etc.

Variation of other quantities in the atmosphere (input of photon dose equivalent, beta radiation, solar radiation, wind speed and trend, altitudinal temperature gradient, relative humidity, air pressure, and quantity of rainfall) is related to the release of radon and/or thoron, as well as their quantification and identification of the trajectory of their movement in the atmosphere. Their interdependence in time is important for correct earthquake prediction.

Simultaneous measurement of radon and/or thoron is conducted at different altitudes in the atmosphere and at different depths in soil, bedrock and water.

The selection of appropriate monitoring point (tectonically disturbed area, geological fault zone, groundwater resource, etc.). Monitoring at different altitudes and depths makes it possible to track radon from its source in the bedrock to the ground surface, whereby significant differences of half-times of decay of radon and thoron can be helpful in general monitoring of the dynamism of soil gases. Of utmost importance is the fact that comphreensive monitoring of the above profiles can help to offset disturbances causing variation of radon and thoron concentration in time, which cannot be attributed to the phenomena of interest. (E.g. the effect of rainfall and snowfall, freezing of the surface layer of soil, temperature inversion.)

Measurement of atmospheric radon at different altitudes is also important in terms of assessment of the altitude of equivalent mixing layer (EML) of the atmosphere, which is important for the evaluation of stability of the atmosphere with regard to the conditions of dispersion. Generally speaking, knowledge of the stability and variability of the atmosphere is necessary for correct interpretation of the changes of measured radon in relation to earthquake prediction. EML corresponds to the height of air column with assumed homogeneous distribution of radon throughout the volume of the column, and its bulk activity equal to that at the ground level. Continuous simultaneous measurement of atmospheric (mainly) radon at selected altitudes including its and thoron's DP, radon and/or thoron in water and soil air, areal velocity of radon and/or thoron exalation from soil, values of atmospheric dose inputs of gamma or beta radiation, solar radiation, gradients of temperature and humidity/moisture in air, soil and water, together with the measurement of precipitation, speed and trend of wind, constitute the base measurement profiles.

General comparison of changes in time and dislocations of planes under "the curves of measurement profiles" is a totally new method of earthquake prediction. So far the existing state of technology has not offered any known instrument that would allow to create such a "base profile".

The following conclusions have been made from the measurement and evaluation of variables of group (A) and variables of group (B):

Experience of the measurement of atmospheric radon (module A) and its DP (module B), in agreement with published data, suggests typical minima at midday ca. from 12 to 4pm, and maxima in the early hours of the day (12 to 4am). The variability is of a typical shape though it is disturbed seasonally (spring, summer, autumn, winter), which is probably related to the aforesaid temperature gradient, i.e. atmospheric stability.

Generally speaking, the minima and maxima of bulk radon activity correspond to the minima and maxima of bulk activities of its DP. Whilst the measured values of BRA vary within well-measurable limits ca. 5-40 Bq/m ³ , equivalent bulk radon activity (EBRA) varies within well-measurable limits ca. 2-20 Bq/m ³ . Whilst BA of ²¹⁸ Po varies in EBRA maxima on the order of tens of Bq/m ³ , BA of ²¹⁴ Pb, ²¹⁴ Bi varies on the order of single Bq/m . The well-measurable coefficient of imbalance varies from 0.5 to 0.7 in agreement with published data. Measured activities of atmospheric DP of thoron vary at the margin of measurability on the order of tenths of Bq/m ³ .

Note 1. EBRA = 0.105 BA ( ²¹⁸ Po) + 0.516 BA ( ²¹⁴ Pb) + 0.379 BA ( ²¹⁴ Bi>, where BAs are directly measured bulk activities of radon DP from the filter (filtering tape). List of illustrations in the drawings

The equipment for the monitoring of changes in the earth's lithosphere and atmosphere according to the invention is illustrated in drawings, which represent the following:

Fig. 1 Block diagram of the equipment according to the invention Obr. 1

Fig. 2 Block diagram of measurement module A

Fig 3 Block diagram of measurement module B

Fig. 4 Block diagram of measurement module C

Fig. 5 Block diagram of measurement module F

Examples of embodiments of the invention

Example 1 :

A modular station for the measurement of natural radioactivity and key disturbing factors allows on the location of interest to determine the characteristic

development in time of the monitored variables in relation to the changes of variables describing ambient effects. Such characteristic changes in time make it possible to eliminate disturbing environmental effects, thus creating a database of filters applicable to the primary time sequences of the variables of interest, which are subsequently analyzed in relation to earthquake prediction.

Primary and filtered time sequences are processed using methods of mathematical statistics, whereby namely long-term trends are compared against the characteristic background of the site and remarkable changes in time (anomalies), which are the subject of interest in relation to changes in the earth's crust. Particularly significant are velocities of increase or decrease of the variables monitored, and the

characteristic shift of time sequences. The modular monitoring system makes it possible at the same time to create calibration protocols for given site using long- term comparison of time sequences of the variables monitored and seismic activity on the site of interest.

Example 2

I. Optimal location of one or more stations in a network for on-line monitoring of the depth/altitude profile of the following continuously measured so-called key variables of interest:

XI = f(t, z) areal velocity of radon and/or thoron exhalation from soil;

X2 = f(t,z) bulk activity of radon and/or thoron from soil gas; X3 = f(t,z) bulk radon activity in the atmosphere;

X4 = f(t, z) bulk activity of radon and/or thoron in water.

At the same time, the "equipment for the monitoring ..." or network thereof measures auxiliary (explanatory) variables from the following groups:

A) Soil:

- soil temperature profiles at two depths minimum Al(t,z)

- soil moisture profiles at two depths minimum A2 (t,z)

B) Air:

- wind trend Bl (t,z) and speed B2 (t.z) at two altitudes minimum

- absolute air humidity at two altitudes minimum B3(t,z)

- solar radiation B4(t,z)

- air temperature gradient, e.g. at 2 m/10 m B5 (t)

- coefficient of imbalance of radon and its DP in two altitude profiles minimum B6 (t,z)

- equivalent bulk thoron activity measured in two altitude profiles minimum B7(t,z)

- dose input of gamma radiation measured in two altitude profiles minimum B8(t,z)

- total beta radiation measured at two altitudes minimum B9(t,z)

C) Water:

- water temperature in two depth profiles minimum Cl(t,z) t

II. Furthermore, monitoring of the time course of key variables Xl(t,z) - X4(t,z) is conducted for long enough time (seasonally, annually, multiannually) against relevant influencing parameters, i.e. continuously measured variables of groups A, B, C, and their background values Xip (t,z) are fixed without disturbing seismic changes (measured with seismograph), using an adequate model, e.g. regression model with additive or multiplicative approach.

III. The following facts are found in relation to different earthquake phenomena: a) statistically significant deviations (shifts and variations) of the measured time sequences of the key variables Xi(t,z) from their relevant background values Xip (t,z), i.e. monitoring variation of time sequences Xi(t,z) vs Xip(t,z) for i = 1-4; b) statistically significant correlations, shifts and variations between signal variables X#ij(t,z)pro i≠j, cleared of the background.

IV. A suitable model of earthquake prediction is designed subsequently, using both examples a) and b).

As Fig. 1 shows, the equipment based on the invention consists for example of

- central control unit 1 (CCU);

- emitting (2) and receiving (6) data modem;

- source block of output feeding voltage 12 V dc (3);

- measurement modules minimum A to F;

- transfer SW Wincentral and visualization SW Visualis;

- waterproof box to allow for field deployment of the instrument.

Fig. 1 shows an example of the configuration of the proposed instrument. Analog and digital outputs of measurement from modules A to F are stored in CCU (1) online in its external memory and, either all at a time or selected ones only, transferred in one-minute intervals, using built-in emitting modem (2) and protocol GPRS, to the user PC with a connected receiving modem (6). Transfer parameters including the selection of measured variables can be configured using the program Wincentral, installed in the user PC. Wincentral furthermore allows remote setting and diagnosing of selected parameters of key HW modules A to F from the user PC, using built-in commands. Thus the concept of the program Wincentral makes it possible to control and read the entire network of stations, each of them including a CCU (1) with any combination of modules A to F. Visualization of files of data received in the user PC is provided by the program Visualis, which also allows to export them to common spreadsheets.

CCU 1 is the heart of the entire system; it logs the relevant data from modules A to F directly in the required variables or converts raw measured data to the required variables by means of mathematical algorithms, using its built-in microprocessor. The overall concept of the station includes remote wireless access to all the CCU functions using the program Wincentral, which allows complete control and setting of all the measuring modules from a single PC. The program Wincentral makes it possible for the CCU to set up a network of measuring stations controlled from a single PC, of which each station must include a central control unit. Power source block can be fed from the grid or battery (4), or solar panels (5).

The functions and connections of measuring modules A to F are as follows:

- Module A offers the possibility of continuous spectrometric and non- spectrometric detection of atmospheric radon and/or thoron. Modul A predstavuje

- Module B offers the possibility of continuous spectrometric measurement of bulk activity of air samples captured on the endless filter, using an appropriate combination of possible couple of detectors (alpha/alpha, alpha/beta,

alpha/gamma) with subsequent determination of bulk activities of individual DP of radon and thoron.

- Module C offers the possibility of simultaneous and continuous measurement of the bulk activity of radon and thoron in soil, and measurement of areal velocity of their exhalation.

- Module D offers the possibility of measurement of photon dose equivalent in the range from natural background up to accident level, or of beta radiation using any kind of measuring instruument, e.g. one based on GM counter and/or coefficient of imbalance F between bulk radon activity and its equivalent bulk activity (EBRA) in the atmosphere.

- Module E includes a set of adequate voltage and amperage sensors, capable of measuring the necessary physical parameters of weather, soil and water (rain gauges, anemometers, thermometers, solar radiation, etc.).

- Module F offers the possibility of simultaneous continuous measurement of bulk radon and throron activity in soil gas, which is sampled from a groundwater resource through a special separation unit with an immersed semi-permeable membrane.

Figure 2 shows possible arrangement of measuring module A for the measurement of atmospheric radon and/or thoron, in the single-detector option for continuous collection of samples of atmospheric radon and/or thoron, based on non- spectrometric detection with a scintillation chamber with ZnS-based

photomultiplier. The sample of active air, stripped of primary DP by filter (18), is pumped by pump (19) through drier (31) and detector (12) with arbitrarily fixed and known flow velocity, measured by airflow gauge (14). During its radioactive decay, radon and/or thoron then causes scintillations within the sensitive volume of the chamber. These are registered by the photomultiplier of the scintillation chamber and taken by the counter as time pulses. The pulse count obtained per unit of time represents the rate of bulk activity of radon and/or thoron. The CCU uses published algorithms to calculate radon and/or thoron values. The results of the measurement are saved in CCU memory and at the same time transferred through the built-in modem online at one-minute intervals to the user PC by means of GPRS protocol.

An advantage of the measuring module is that it offers the choice of manual or remote setting of the detector's own background using radon-free technical gas, contained in pressure cylinder (28), with the aid of gas management system (20, 22, 23, 24). Menu of the evaluation unit (11) can be used for manual setting, the evaluation unit consistsing of a two-track multichannel analyzer (42) (MCA, MC 2000). The remote option is provided by the CCU on command from the user PC.

The two-track multichannel analyzer 42 (MCA) furthermore allows another simultaneous detection of radon and/or thoron by connecting an additional, spectrometric or non-spectrometric detector of alpha, beta or gamma radiation. The stability of the detector in use is achieved by means of working standard ²⁴¹ Am (29), which is inserted into the detection space of the detector when needed, and is controlled from the user PC by means of an electro-magnetic valve.

To allow the use of module A at low temperature, its critical parts, i.e.

electromagnetic valves (15, 20) are insulated and tempered using adjustable thermostats (21).

Temperature sensor (13) helps to offset the effect of temperature variation, which affects namely the response of detector photomultiplier. Exchangeable filter (31) capturing air humidity is installed to eliminate the negative effect of condensation of air humidity inside the detector, and to improve the efficiency of detection and spectrometry of the measuring instruments; furthermore, optional heating of the adequately insulated detector is installed to react to outside air humidity, using the adjustable air humidity sensor of the hygrostat (30). Samples can be collected from a grommet of any size and shape, fixed in any suitable way and opening on the outside of the casing at a suitable collecting height above ground. Simultaneous measurement of the height profile of atmospheric radon and/or thoron is possible using an additional detector or setting up a network of measuring stations.

Figure 3 shows a possible arrangement of measuring module B to measure samples of atmospheric bulk activities of DP of radon and thoron, captured on the endless filter (filtering tape). DP of radon and thoron in the atmosphere are fixed to aerosol. This is why they are detected applying the well-known principle of collection on filter during the suction of a defined volume of air sample at a known flow velocity through sensor (43) and filtering tape (50) using a powerful pump (44). The bulk activity of DP is then calculated from the known volume of air transiting the filter per unit of time and their activity determined from the filter using a spectroscopic semiconductor detector. Alpha radiation emanating from the DP is used for the detection, as it allows registering a sufficient count of signal pulses. In the proposed embodiment, the sample collected at filter is first subjected to the first detector (46), by whose means and using adequate timing of the measurement (choice of measurement times and intervals between them) the bulk activity of individual short-time radon DP ( ²¹⁸ Po, ²¹⁴ Pb, ²¹⁴ Bi) is determined. The sample is then subjected to the second detector (47) for analogous determination, again with adequate timing, of the bulk activity of short-time thoron DP ( ²¹² Pb, ²¹² Bi). When thoron DP measurement is finished, air samples are collected again from the "endless" filter (filter coil continuously winds off and then winds back to the beginning instantaneously) and the entire measurement cycle is repeated. The proposed algorithm provides for both spectrometric and non-spectrometric determination of the bulk activity of individual DP of radon and thoron, the necessary measurement of the background of the tape, simultaneous calibration of both detectors, and irradiation of the tape by means of the couple of double standards ⁴¹ Am (53, 54). A certain disadvantage of the use of detection of alpha radiation from the activity of the DP captured on the filter seems to be their self-absorption in the volume of the filter, which is a function of the change of its areal mass and subsequently causes deviations from the identified detection efficiency of the detectors using the double calibrating standard ²⁴¹ Am (53). The module includes the second double standard ²⁴¹ Am (54), which allows for the irradiation of the tape (always while using the two detectors (46, 47) and subsequent determination of the changes of areal mass of the tape (due to increasing contamination of the tape in its multiple use), based on the measured changes of amplitude spectra, obtained in irradiation. The calculation algorithm then allows correcting true detection efficiency to the changes found of the areal mass of the tape.

The movement of the tape is controlled by the control unit (41) and the alpha spectra measured by means of the couples of detectors (46, 47) are evaluated using the two-track multichannel analyzer 42 (MC 2000). The proposed embodiment allows the control of the functions of tape movement, evaluation of the measured alpha spectra, measurement of the background, and the function of the ^{2 1} Am double standards either manually from the CCU keyboard, or remotely from the user PC.

The collection duct for samples of active air (49), of appropriate size and length, can open in any suitable way from the cover box of the instrument. Simultaneous detection of radon and thoron DP is secured by the location of the network of measuring instruments at appropriate heights.

Module D

Measuring module D provides for continuous measurement of the input of photon dose equivalent or beta radiation.

Measurement of dose inputs from the module, adequately shielded from the effect of radon and thoron deposits on ground surface, allows for quantitative assessment of atmospheric variability of radon and thoron DP.

Module E

In principle, module E consists of amperage or voltage transducers of variables measured a) in the atmosphere, b) in soil and c) in water, which generally serve as auxiliary variables for the interpretation of diffusion of the profile of the key variables and the stability of the atmosphere, measured by modules A to C. All the transducers are connected directly into the analog and digital CCU inputs and are located either on a measuring mast, ca. 10 m high, at the measuring station, or in soil and water according to their use.

In the atmosphere. With regard to the interpretation of the diffusion of the monitored profile of the measured variables, the most important one is temperature difference (gradient = vector) between the ground collection layer of air, e.g. at 2 m, and that at 10 m. Its absolute value and trend provide for an important indicator of the stability of ground atmosphere. Typical daily gradients ca. 0-3 °C in upward direction represent the lowest stability of the atmosphere with good mixing, explicitly accompanied by typical afternoon (12 to 3pm) daily minima of radon and/or thoron and their short-time DP. The gradient is of the opposite trend for the rest of the day, and the atmosphere becomes more stable with less mixing and consequently higher values of atmospheric radon and/or thoron and their DP. As the gradient is primarily influenced by the intensity of insolation, the choice of solar radiation sensor also matters because it allows direct quantification of the time of insolation. The speed and direction of the movement of air masses (or the monitored profile) at defined heights (10 m in this case, the height of the mast) should then be quantified by the transducer of wind speed and trend.

In water and soil.

Fig. 4 shows measuring module C. Module C enables simultaneous continuous measurement of bulk radon and thoron activity in soil gas, and the velocity of its exhalation from the surface layer of soil, using ionizing chambers through which air flows, coming from samples collected in ground probes or from exhalation vessel installed on the surface. The system is able to display data on the screen of the local control and evaluation unit ERM-4, which, following the concept of the measuring station, sends them on after processing through the central control unit 1 of the station E-log to the user PC.

Block diagram of the module is shown in Fig. 4.

Module C consists of

- evaluation and control unit (79), which, by means of measuring very low electric currents caused by ionization of air in the sensitive space of the detector, allows for simultaneous evaluation of bulk radon and thoron activity from individual sampling tracks of air gas collected at different depths (61, 62) and exhalation vessels installed on ground surface (63);

- two flow detectors, connected in series, for each sampling track (67, 68, 69, 70, 71, 72), separated by a delay unit to eliminate thoron from the sampled gas (64, 65, 66), where the sampled gas is also the working gas of the detectors, and each sampling track includes a flow pump (76, 77, 78) with recording (73, 74, 75) of the flow of air along the sampling track;

- closed sampling track with exhalation vessel, with specially designed collection hoses to prevent freezing of water vapour along the sampling track and

- open sampling track installed at defined depth in bedrock with specially designed i collection hoses to prevent freezing of water vapour along the sampling track.

Fig. 5 shows block diagram of measuring module F. Module F enables

simultaneous continuous measurement of bulk radon and thoron activity in soil gas, sampled from a groundwater resource through a special separation unit with ; semi-permeable membrane. The system is able to display data on the screen of its local control and evaluation unit ERM-4, which, following the concept of the measuring station, sends them on after processing through the CCU E-log to the user PC.

Module F consists of

a) evaluation and control unit (90), which, by means of measuring very low electric currents caused by ionization of air in the sensitive space of the detectors, allows for simultaneous evaluation of bulk radon and thoron activity from the sampling track for collection of soil gas, separated from groundwater resource (81).

b) two flow detectors, connected in series, for each sampling track (85, 87), separated by a delay unit (86) to eliminate thoron from the sampled gas, where the sampled gas is also the working gas of the detectors, and each samplmg track includes a flow pump (89) with recording of the flow of air along the sampling track (88);

c) closed sampling track with special separation unit (84), providing for radon transfer from water through semi-permeable membrane (83) to the sampling track; d) separation vessel with special semi-permeable membrane of a defined length and diameter, enabling one-off or continuous collection of water from a groundwater resource.

List of reference characters

A measuring module A

B measuring module B

C measuring module C

D measuring module D

E measuring module E

F measuring module F

1 central control unit

2 emitting modem (GPRS)

3 source block

4 batteries

5 solar cable

6 PC 6 with receiving module

11 monitoring and evaluation unit

12 scintillation chamber 12 for radon detection

13 photomultiplier temperature sensor 13

14 air flow gauge

15 tempered electromagnetic valve

16 exit valve of scintillation chamber

17 entry valve of scintillation chamber

18 filter

19 pump

20 tempered electromagnetic valve 20 with a nozzle

21 Fluid thermos regulator 21

22 output closure 22 of reduction valve

23 reduction valve

24 pressure sensor

25 low pressure gauge

] 26 pressure cylinder manometer 26

27 pressure cylinder closure 27

28 pressure cylinder 28 (background gas)

29 working standard 29

30 hygrostat

; 31 drying agent

41 control unit

42 two-track multichannel analyser air flow sensor

pump

filtering tape winding coil 45

, 47 detectors 46 (1) and 47 (2)

mechanical travel block 48 of filtering tape suction neck 49 for air sample collection filtering tape

spare coil 51 of filtering tape

preamplifiers 52 of detectors 1 ,2

couple of working standards 53 of stability of detectors 1, 2

couple of working standards 54 of tape contamination , 62 collection depths

exhalation vessels

, 65, 66 delay unit

-72 sampling track

, 74, 45 record 73, 74, 75 of air flow along sampling track, 77, 78 flow pump

evaluation and control unit

ground water source

record 82 of air flow along sampling track semi-permeable membrane

separation unit

, 87 sampling track

delay unit

record of air flow 88 along sampling track flow pump

evaluation and control unit