Characterization of groundwater response and hydrogeological properties surrounding the Pohang earthquake, South Korea.
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| Title: | Characterization of groundwater response and hydrogeological properties surrounding the Pohang earthquake, South Korea. |
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| Alternate Title: | Caracterización de la respuesta a las aguas subterráneas y propiedades hidrogeológicas con relación al terremoto de Pohang, Corea del Sur. Caractérisation de la réponse des eaux souterraines et des propriétés hydrogéologiques dans le périmètre du séisme de Pohang, Corée du Sud. Caracterização da resposta da água subterrânea e propriedades hidrogeológicas em torno do terremoto de Pohang, Coreia do Sul. 韩国Pohang地震周边地下水响应与水文地质特性表征. |
| Authors: | Ryu, Han-Sun1 (AUTHOR) rhs@kangwon.ac.kr, Lee, Jin-Yong1 (AUTHOR) hydrolee@kangwon.ac.kr, Kim, Heejung1 (AUTHOR) hydroqueen@kangwon.ac.kr, Jeong, Darae2 (AUTHOR) tinayoyo@kangwon.ac.kr |
| Source: | Hydrogeology Journal. Jun2026, Vol. 34 Issue 4, p783-799. 17p. |
| Subjects: | Earthquakes, Groundwater, Permian Period, Geothermal engineering, Hydraulic conductivity, Aquifers |
| Geographic Terms: | South Korea |
| Abstract (English): | The hydrogeological properties in and around two geothermal wells at depths of approximately 4300 m in the Pohang Enhanced Geothermal System (EGS), South Korea, an area of public concern due to the 15 November 2017 Pohang earthquake, were examined. The subsurface at the study site is geologically composed of Permian granodiorite; Cretaceous andesite, rhyolite, sandstone, and tuff; and Tertiary tuff and mudstone. Hydraulic conductivities of the subsurface to a depth of 250 m ranged from 1.46 × 10−6 to 4.65 × 10−1 cm/s and exhibited an exponentially decreasing trend with depth. The hydraulic conductivities of the two EGS wells, screened several hundred meters from the well bottoms, ranged from 4.54 × 10−12 to 1.50 × 10−10 cm/s, which are lower than the predicted values based on exponential regression. This suggests that the five hydraulic stimulations conducted for the EGS were not effective. Some surrounding wells exhibited water level declines in response to the earthquake, particularly those screened to relatively deep bedrock aquifers. Over the long-term (2016–2018), most surrounding wells showed generally declining groundwater levels. This overall decline was mainly attributed to decreasing rainfall, while the influence of groundwater use was relatively minor during this period. The findings contribute to a better understanding of the origin and mechanism of the Pohang earthquake. [ABSTRACT FROM AUTHOR] |
| Abstract (Spanish): | RESUMEN: Se examinaron las propiedades hidrogeológicas en y alrededor de dos pozos geotérmicos a profundidades aproximadas de 4300 m en el Pohang Enhanced Geotheral System (EGS), Corea del Sur, un área de interés público debido al terremoto de Pohang del 15 de noviembre de 2017. El subsuelo del yacimiento de estudio está geológicamente compuesto de granodiorita pérmica; andesita, riolita, arenisca y toba del Cretácico; y toba y lutitas terciarias. Las conductividades hidráulicas del subsuelo hasta una profundidad de 250 m oscilaron entre 1,46×10−6 y 4,65×10−1 cm/s y mostraron una tendencia exponencial decreciente con la profundidad. Las conductividades hidráulicas de los dos pozos EGS, situados a varios cientos de metros del fondo del pozo, oscilaron entre 4,54×10−12 y 1,50×10−10 cm/s, que son inferiores a los valores predichos basados en la regresión exponencial. Esto sugiere que las cinco estimulaciones hidráulicas llevadas a cabo para el EGS no fueron efectivas. Algunos pozos circundantes mostraron descensos en el nivel del agua en respuesta al terremoto, especialmente aquellos filtrados en acuíferos rocosos relativamente profundos. A largo plazo (2016–2018), la mayoría de los pozos circundantes mostraron un descenso general de los niveles de agua subterránea. Este descenso general se atribuyó principalmente a la disminución de las precipitaciones, mientras que la influencia del uso de agua subterránea fue relativamente menor durante este periodo. Los hallazgos contribuyen a una mejor comprensión del origen y el mecanismo del terremoto de Pohang. [ABSTRACT FROM AUTHOR] |
| Abstract (French): | RESUME: Les propriétés hydrogéologiques au sein et autour de deux puits géothermiques profonds de 4300 m environ, implantés dans le Système Géothermal Stimulé de Pohang (SGS), Corée du Sud, une zone d'inquiétude du public du fait du séisme de Pohang du 15 novembre 2017, sont examinées. Le sous-sol du site d'étude est constitué au plan géologique de granodiorites du Permien, d'andésite, rhyolite, grès et tufs du Crétacé ; et de tufs et argilites du Tertiaire. Les conductivités hydrauliques du sous-sol à une profondeur de 250 m étaient comprises entre 1.46×10−6 et 4.65×10−1 cm/s et montraient une tendance à décroître exponentiellement avec la profondeur. Les conductivités hydrauliques des deux puits du SGS, mesurées à plusieurs centaines de mètres du fond des ouvrages, allaient de 4.54×10−12 à 1.50×10−10 cm/s, valeurs inférieures à celles prédites sur la base d'une régression exponentielle. Ceci suggère que les cinq stimulations hydrauliques réalisées sur le SGS n'ont pas été efficaces. Certains puits environnants ont montré des baisses du niveau de l'eau à la suite du séisme, en particulier celles mesurées dans les aquifères relativement profonds du substratum. Sur le long terme (2016-2018), la plupart des puits alentours ont montré des niveaux d'eau souterraine généralement en baisse. Cette baisse générale a été attribuée à une décroissance des précipitations, alors que l'influence de l'utilisation de l'eau souterraine a été relativement mineure pendant cette période. Ces résultats contribuent à une meilleure connaissance de l'origine et du mécanisme du séisme de Pohang. [ABSTRACT FROM AUTHOR] |
| Abstract (Portuguese): | RESUMO: Foram examinadas as propriedades hidrogeológicas em dois poços geotérmicos e arredores a profundidades de aproximadamente 4300 m no Sistema Geotérmico Aprimorado de Pohang (SGA), Coreia do Sul, uma área de interesse público devido ao terremoto de Pohang em 15 de novembro de 2017. O subsolo do local de estudo é geologicamente composto por granodiorito do Permiano; andesito, riolito, arenito e tufo do Cretáceo; e tufo terciário e argilito de argilito. As condutividades hidráulicas do subsolo até uma profundidade de 250 m variaram de 1.46×10−6 a 4.65×10−1 cm/s e apresentaram uma tendência exponencialmente decrescente com a profundidade. As condutividades hidráulicas dos dois poços SGA, selecionadas a várias centenas de metros do fundo dos poços, variaram de 4.54×10−12 a 1.50×10−10⁰ cm/s, que são menores que os valores previstos baseados em regressão exponencial. Isso sugere que as cinco estimulações hidráulicas realizadas para o SGA não foram eficazes. Alguns poços ao redor apresentaram quedas no nível da água em resposta ao terremoto, especialmente aqueles filtrados em aquíferos rochosos relativamente profundos. No longo prazo (2016–2018), a maioria dos poços ao redor apresentou níveis de água subterrânea geralmente em declínio. Esse declínio geral foi atribuído principalmente à diminuição das chuvas, enquanto a influência do uso de água subterrânea foi relativamente pequena durante esse período. As descobertas contribuem para uma melhor compreensão da origem e do mecanismo do terremoto de Pohang. [ABSTRACT FROM AUTHOR] |
| Abstract (Chinese): | 摘要: 本文针对2017年11月15日韩国Pohang地震引发公众关注的Pohang增强型地热系统（EGS）区域，开展了两口井深约4,300 m地热井及其周边地下介质水文地质特性的研究。研究区地下地质组成包括二叠纪花岗闪长岩、白垩纪安山岩—流纹岩—砂岩—凝灰岩以及第三纪凝灰岩与泥岩。0–250 m 深度范围内的渗透系数为 1.46 × 10-6 至 4.65 × 10-1 cm/s，且随深度增加呈指数衰减趋势。两口EGS井的筛管（开孔）段位于井底以上数百米处，其渗透系数为 4.54 × 10−12 至 1.50 × 10-10 cm/s，低于基于指数回归预测的数值，表明为EGS实施的5次水力增渗效果并不显著。部分周边观测井在地震发生后出现地下水位下降，尤其是筛管段位于较深基岩含水层中的井。就长期变化（2016–2018年）而言，多数周边井地下水位总体呈下降趋势，该整体下降主要归因于降雨减少，而同期地下水开采的影响相对较小。上述结果有助于加深对Pohang地震成因及其发生机制的认识。 [ABSTRACT FROM AUTHOR] |
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| Database: | Engineering Source |
| Abstract: | The hydrogeological properties in and around two geothermal wells at depths of approximately 4300 m in the Pohang Enhanced Geothermal System (EGS), South Korea, an area of public concern due to the 15 November 2017 Pohang earthquake, were examined. The subsurface at the study site is geologically composed of Permian granodiorite; Cretaceous andesite, rhyolite, sandstone, and tuff; and Tertiary tuff and mudstone. Hydraulic conductivities of the subsurface to a depth of 250 m ranged from 1.46 × 10−6 to 4.65 × 10−1 cm/s and exhibited an exponentially decreasing trend with depth. The hydraulic conductivities of the two EGS wells, screened several hundred meters from the well bottoms, ranged from 4.54 × 10−12 to 1.50 × 10−10 cm/s, which are lower than the predicted values based on exponential regression. This suggests that the five hydraulic stimulations conducted for the EGS were not effective. Some surrounding wells exhibited water level declines in response to the earthquake, particularly those screened to relatively deep bedrock aquifers. Over the long-term (2016–2018), most surrounding wells showed generally declining groundwater levels. This overall decline was mainly attributed to decreasing rainfall, while the influence of groundwater use was relatively minor during this period. The findings contribute to a better understanding of the origin and mechanism of the Pohang earthquake. [ABSTRACT FROM AUTHOR] |
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| ISSN: | 14312174 |
| DOI: | 10.1007/s10040-026-03049-8 |
