Implementation of a Radon Monitoring Network in a Seismic Area

Abstract

Large-scale radon monitoring is carried out due to the fact that it is directly responsible for public health. European Directive 2013/59/EURATOM has been transposed into the legislation of several countries and provides for the need for long-term monitoring of radon in homes and workplaces by setting the average annual reference level at 300 Bq/m3. At the same time, radon is a precursor factor, its emission being correlated with seismic and volcanic activity. In this case, the protection of the population is ensured by a forecast similar to a meteorological one. The NIEP (National Institute for Earth Physics) is developing a multidisciplinary real-time monitoring network in the most dangerous seismic area in Romania, Vrancea. This is located at the bend of the Carpathian Mountains and is characterized by deep earthquakes (over 80 km), with destructive effects over large distances. Implementing a multidisciplinary monitoring network that includes radon, involves finding the locations and equipment that will give the best results. There is no generic solution for achieving this, because the geological structure depends on the monitoring area, and in most cases the equipment does not offer the ability to transmit data in real time. The positioning of the monitoring stations was based on fault maps of the Vrancea area. Depending on the results, some of the locations were changed in pursuit of a correlation with zonal seismicity. Through repeated tests, we established the optimal sampling rate for minimizing errors, maintaining measurement accuracy, and ensuring the detection of anomalies in real time. The radon 222Rn was determined by the number of counts and ROI1 (region of interest) values, depending on the particularities of the equipment. Finally, we managed to establish a real-time radon monitoring network which transmits data to geophysical platforms and makes correlations with the seismicity in the Vrancea area. The equipment, designed to store data for long periods of time then manually download it with manufacturers’ applications, now works in real time, after we implemented software designed specifically for this purpose.

Analysis of Radon Measurements in Relation to Daily Seismic Activity Rates in the Vrancea Region, Romania

“…Radon monitoring occurs indoors in the air near the ground using Radon Scout PLUS sensors, produced by SARAD, at a sampling rate of 3 h. The seismicity in the area is characterised by shallow seismicity with moderate earthquakes (Mw < 5.6) together with intermediate-depth activity featuring strong earthquakes (Figure 1). More information about the deployed monitoring network can be found in [22]. For the present study, the measurements taken at the BISRd station have been us as it is located in the most central part of the Vrancea zone and covers a longer period time without gaps, spikes, or corrupted data.…”

Radon Hazard of the Zhurinsky Fault for the Population in the Kuznetsk Coal Basin: Primary Results

“…In some cases, fault zones, in the absence of modern geodynamic processes, become non-permeable due to the filling of cracks with secondary carbonate, siliceous and other minerals. Also, the radonometric survey of faults allows for the prediction of earthquakes and rock and tectonic shocks during engineering and geological explorations [17,[26][27][28].…”

The Results and Developments of the Radon Monitoring Network in Seismic Areas

“…This article presents the evolution of implementations and results from the development process of a radon monitoring network as part of a multidisciplinary approach by the National Institute of Earth Physics in Romania [1][2][3]. The main goal is to create an automated seismic forecasting system (OEF-Operational Earthquake Forecasting) based on real-time data such as radon, CO 2 , air ionization, telluric currents, magnetic field, ULF-VLF radio waves, and seismic information.…”

“…For this reason, the use of a trigger threshold per level for anomaly detection is not possible, but a real-time OEF (Operational Earthquake Forecasting) can be implemented such as in [2]. In [3,5], an application for the Vrancea zone (the curvature area of the Carpathian Mountains) is presented; in [4] is the forecasting is for Japan; Reference [6] used a general monitoring of electromagnetic emissions (EM) (we tried something similar, but the results are not convincing for Vrancea [10]); and Reference [7] prospected for operational forecasting of earthquakes in Europe using seismic information, but the catalogs are not homogeneous and the seismicity patterns are too different for different areas. The authors of the article [8] specify the difference between forecast and prediction, emphasizing the difficulties of using it in general the 'time-dependent seismic hazards to help communities prepare for potentially destructive earthquakes.…”