• Title/Summary/Keyword: 포항

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Large-scale, Miocene Mud Intrusion into the Overlying Pleistocene Coastal Sediment, Pohang City, SE Korea: Deformation Mechanism, Trigger, and Paleo-seismological Implication for the 2017 Pohang Earthquakes

  • Gihm, Yong Sik;Ko, Kyoungtae;Choi, Jin-Hyuk;Choi, Sung-ja
    • Economic and Environmental Geology
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    • v.53 no.5
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    • pp.585-596
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    • 2020
  • The 2017 Pohang Earthquakes occurred near a drill site in the Pohang Enhanced Geothermal System. Water injected for well stimulation was believed to have reactivated the buried near-critically stressed Miocene faults by the accumulation of the Quaternary tectonic strain. However, surface expressions of the Quaternary tectonic activity had not been reported near the epicenter of the earthquakes before the site construction. Unusual, large-scale water-escaped structures were identified 4 km away from the epicenter during a post-seismic investigation. The water-escaped structures comprise Miocene mudstones injected into overlying Pleistocene coastal sediments that formed during Marine Isotope Stage 5. This indicates the vulnerable state of the mudstones long after deposition, resulted from the combined effects of rapid tectonic uplift (before significant diagenesis) and the development of an aquifer at their unconformable interface of the mudstone. Based on the detailed field analysis and consideration of all possible endogenic triggers, we interpreted the structures to have been formed by elevated pore pressures in the mudstones (thixotropy), triggered by cyclic ground motion during the earthquakes. This interpretation is strengthened by the presence of faults 400 m from the study area, which cut unconsolidated coastal sediment deposited after Marine Isotope Stage 5. Geological context, including high rates of tectonic uplift in SE Korea, paleo-seismological research on Quaternary faults near the study area, and historical records of paleoearthquakes in SE Korea, also support the interpretation. Thus, epicenter and surrounding areas of the 2017 Pohang Earthquake are considered as a paleoseismologically active area, and the causative fault of the 2017 Pohang Earthquakes was expected to be nearly critical state.

Health and Environmental Risk Assessment of Pollutants in Pohang (포항지역 오염물질 보건.환경 위해성 평가 -미세먼지의 발생특성 및 농도분포를 중심으로-)

  • Jung, Jong-Hyeon;Choi, Won-Joon;Leem, Heon-Ho;Shon, Byung-Hyun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.7
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    • pp.2719-2726
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    • 2010
  • The purpose of this study was to investigate the scientific basic grounds for the assessment of health and environmental diseases resulting from air pollutants in Pohang. For this study, we investigated pollutants, weather characteristics and concentration distribution of fine particles ($PM_10$) yearly and each season, using data from Air Quality Monitoring Stations. The properties of concentration distribution and seasonal fluctuation of $PM_10$ were studied qualitatively and quantitatively using CALPUFF, air dispersion model. The average concentration of $PM_10$ for each season was spring($75.7{\mu}g/m^3$)>summer($56.8{\mu}g/m^3$)>winter($53.6{\mu}g/m^3$)>fall( $52.7{\mu}g/m^3$). In the case of spring, high concentrations appear due to the Asian dust frequently occurring. The contributions of $PM_10$ classified by the types of pollution source in Pohang were point source 62%>mobile source 33%>area source 5%. An important point is that 97% of emissions were produced from the iron manufacture in steel industry. Therefore, it is necessary to control the emission sources of pollutants and to construct an observation system at Pohang steel industrial complex from now on. It’s time to control the risk factors for health and environmental disease to protect the health of resident in Pohang and its neighboring areas.

Current Status of By-products Generation and Industrial Symbiosis Network in Pohang, South Korea (포항 산업단지 부산물 발생 및 산업공생 네트워크 현황)

  • Park, Jong-Hun;Jung, In-Gyung;Seo, Jae-Gun;Kim, Sang-Hyoun
    • Journal of the Korea Organic Resources Recycling Association
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    • v.23 no.1
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    • pp.63-69
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    • 2015
  • This work aimed to analyze current status of by-products generation and industrial symbiosis network in Pohang steel industrial complex, South Korea. Pohang is the largest generating city of both total and the non-recycled industrial waste in Gyeongsangbuk-do, and most of the waste is generated from Pohang steel industrial park. Symbiosis map in Pohang steel industrial park shows that most of the current material symbiosis in the industrial park is for waste refractories and slag.