• Proceedings of the KSEEG Conference
• /
• 2007.04a
• /
• pp.48-50
• /
• 2007

• Proceedings of the Korea Water Resources Association Conference
• /
• 2022.05a
• /
• pp.383-383
• /
• 2022

기존 큰 지진을 대상으로 한 많은 연구결과들을 살펴보면, 큰 지진이 발생하기 전에 토양 속에 존재하는 다양한 인자들 중에 라돈(²²²Rn, 반감기=3.82일) 농도가 비정상적으로 증가하는 현상을 나타낸다. 이러한 결과들은 라돈발생의 경향성을 분석한다면, 지진발생에 대한 전조증상이나 예측이 가능함을 나타낸다. 본 연구에서는 포항지역을 중심으로 지진발생에 대한 전조증상이나 모니터링을 분석하기 위해 지하수 관측소에 설치된 라돈 관측기기에서 라돈 관측자료를 수집하고 이를 활용하는 연구를 수행하였다. 라돈 관측자료 기간은 2019년 11월부터 2020년 9월까지의 자료이며, 라돈인자 뿐만 아니라 지하수위, 강수량, 수온인자를 같이 분석하였으며, 동일기간 동안 발생한 진도 2 이상의 지진사례 6개(E1(M_L 3.5): 2019.12.30.; E2(M_L 3.2): 2020.01.30.; E3(M_L 2.4): 2020.02.09.; E4(M_L 2.7): 2020.02.16.; E5(M_L 2.8): 2020.05.27.; E6(M_L 2.1): 2020.09.22.)를 대상으로 하였다. 지진발생의 전조증상이 나타나는 지역을 분석하기 위해 Dobrovolsky radius values (Dobrovolsky et al., 1979)와 Harversine 관계식을 적용하였다. 적용결과, 시간적 분석에서 라돈의 증감 경향성이 지진발생의 전조증상과 유의미한 상관성이 있음을 확인하였으며, 공간적인 분석에서도 유의미하지는 않으나 상관성이 나타났다. 그 외 지하수위는 상관성이 어느 정도 나타났으나 강수량은 유의미한 결과를 나타내지는 않았다. 따라서 라돈을 활용한다면 지진발생의 전조증상을 시공간적으로 파악할 수 있음을 확인하였다.

• Journal of Korea Water Resources Association
• /
• v.53 no.7
• /
• pp.507-519
• /
• 2020

This study developed the radon measurement system that can be used for crustal movement monitoring and seismic occurrence and prediction, and compared and analyzed the results of test-operated radon measurement system and observed seismic occurrence cases. First, the developed radon measurement system consists of an NB-IoT radon measurement device, data center, data analysis, and data supply server. Because the measured radon data can be remotely trasmitted by using NB-IoT, this system is very suitable for installation and operation in unmaaned groundwater station. Second, the developed radon measurement device was test-operated at two groundwater stations in Gimpo from May to July 2019. The measured radon data was compared with the groundwater-level and electrical conductivity measurement data, and it was confirmed that the radon measurement device developed in this study has some potential for commercialization. Finally, from November 2019 to February 2020, three observed seismic cases and daily measured radon, groundwater-level, electrical conductivity data by the NB-IoT radon measurement device installed at three groundwater stations in Pohang, which is a test-bed, were compared and analyzed. As a result of the analysis, it was confirmed that the seismic occurrence correlated with radon, groundwater level, and electrical conductivity and all of these measured data will be able to provide basic data to help in seismic monitoring and prediction in the future.

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2005.11a
• /
• pp.376-378
• /
• 2005

• The Journal of the Petrological Society of Korea
• /
• v.18 no.4
• /
• pp.279-291
• /
• 2009

Radon is a natural radionuclide originated from radioactive decay of radium in rocks and soil. It is colorless, odorless and tasteless elements that mainly distributed as gaseous phase in soil pore space. The present study analyzed the characteristics of long-term radon variation in granitic residual soil at Mt. Guemjeong in Guemjeong-gu, Busan and determined the effects of atmospheric temperature, rainfall and soil temperature and moisture. Periodic measurements of radon concentrations in soil gas were conducted by applying two types of in-situ monitoring methods (chamber system and tubing system). Radon concentration in soil gas was highest in summer and lowest in winter. The variations in soil temperature and atmospheric temperature were most effective factors in the long-term radon variations and showed positive co-relations. The air circulation between soil air and atmosphere by the temperature difference between soil and atmosphere was analyzed a major cause of the variation. However, other factors such as atmospheric pressure, rainfall and soil moisture were analyzed relatively less effective.

• Analytical Science and Technology
• /
• v.25 no.1
• /
• pp.7-13
• /
• 2012

The real-time monitoring of radon ($^{222}Rn$) concentrations has been carried out to evaluate the background concentration level of atmospheric radon in Gosan site, Jeju Island. The mean concentration of radon for the recent 10 years was 2831 $mBq/m^3$ (0.077 pCi/L), which was 19.5 time lower than that of indoor radon in Korea. The seasonal concentrations were 2657, 2071, 3249, 3384 $mBq/m^3$ respectively for spring, summer, fall, and winter seasons. In monthly comparison, the radon concentrations were high in October and low in July. The hourly concentrations have increased during the nighttime, showing 3666 $mBq/m^3$ at 7 a.m., and decreased relatively during the daytime, showing 2755 $mBq/m^3$ at 2~3 p.m. From the back trajectory analysis, the radon concentrations showed higher values when the air mass was moved from the Asia continent to Jeju area, on the other hand, it showed low values when it was moved from the North Pacific Ocean.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.15 no.6
• /
• pp.1217-1222
• /
• 2020

Currently, studies on environmental pollution are being conducted in worldwide including Korea. Among them, various efforts are being made to prevent the health and environmental pollution of the people nationwide by keeping and managing the indoor air of various facilities used by many users. In particular, it is suggested that many people who visit medical institutions have diseases or illnesses and may have a significant impact on chronic diseases such as headache, depression, neuroticism, heart disease, and cancer related to indoor air pollution. Considering this situation, this paper is expected to provide comfortable and clean indoor environment to the inmate by providing central monitoring of air pollution and automatic call function of the person in charge through indoor air monitoring IoT system to be applied to medical institutions.

• Journal of Radiation Protection and Research
• /
• v.25 no.4
• /
• pp.207-216
• /
• 2000

Continuous measurements of radon progeny concentrations in the open atmosphere and measurements of meteorological parameters were performed in Tajeon, using a continuous gross alpha/beta aerosol monitor and a weather measuring equipment between July 1999 and July 2000. These data were analyzed for half-hourly, daily, and seasonal variations. The distribution of daily averaged equilibrium equivalent radon concentration$(EEC_{Rn})$ had an arithmetic mean value of $11.3{\pm}5.86Bqm^{-3}$ with the coefficient of variation of about 50% and the geometric mean was $10.3Bqm^{-3}$. The $EEC_{Rn}$ varies between 0.83 and $43.3Bqm^{-3}$, depending on time of day and weather conditions. Half-hourly averaged data indicated a diurnal pattern with the outdoor $EEC_{Rn}$ reaching a maximum at sunrise and a minimum at sunset. The pattern of the seasonal variation of the $EEC_{Rn}$ in Taejon had a tendency of minimum concentration occurring in the summer(July) and maximum concentration occurring in the late autumn(November). But the seasonal variation of the $EEC_{Rn}$ is expect to vary greatly from place to place. The outdoor $EEC_{Rn}$ was highly dependent on the local climate features. Particularly the $EEC_{Rn}$an rapidly drops less than $5Bqm^{-3}$ in case of blowing heavily higher than wind speed of $6msec^{-1}$, reversely the days with more than $30Bqm^{-3}$ were at a calm weather condition with the wind speed of lower than $1msec^{-1}$.

• The Journal of Engineering Geology
• /
• v.28 no.2
• /
• pp.313-324
• /
• 2018

In order to study the earthquake precursor in the Korean peninsula, long-term variations of chemical composition, radon-222, and water level were measured at depths (-60 m, -100 m) in the groundwater monitoring wells of the Daejeon and the Cheongwon area. The pH and electrical conductivity of groundwater in the monitoring wells showed some relationship with the Pohang earthquake. The ${HCO_3}^-$ and $Cl^-$ concentration of groundwater in the Daejeon and $Mg^{2+}$, $Cl^-$ and ${NO_3}^-$ in the Cheongwon showed some relation with the Pohang earthquake. However, it is not distinct to find the relationship between their variation and earthquake. The radon-222 concentration in Daejeon was observed a significant increase from a minimum of 162 Bq/L prior to the earthquake to 573 Bq/L right after the earthquake, that indicating a strong correlation with earthquakes. In the case of groundwater levels, it can not find some correlation between earthquakes and continuous decreasing trend in the monitoring wells of Daejeon and Cheongwon area. However, water level of a national groundwater observation well within 10 kilometers of Pohang epicenter was recorded as an abrupt drop right before the earthquake. Conclusively, although the location of monitoring wells is more than 180 kilometers apart from the epicenter of the Pohang earthquake, the radon gas in groundwater can be considered as a reliable candidate among earthquake precursors. The pH, electrical conductivity, ${HCO_3}^-$ and $Cl^-$ among hydrochemicals showed some correlation with earthquake should be monitored during a longer term to recognize distinctly as a precursor of earthquake.