• Economic and Environmental Geology
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• v.39 no.5 s.180
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• pp.597-605
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• 2006

In this study, we examined the applicability of 3-D electrical resistivity survey to detect underground cavities within ground subsidence area at the field test site, located at Yongweol-ri, Muan-gun in Korea. Underground cavities are widely present within the limesilicate bedrock overlain by the alluvial deposits in the area of the test site where the ground subsidences have occurred in the past. The limesilicate cavities are mostly filled with groundwater and clays in the test site. Thus, cavities have low electrical resistivity compared to the surrounding host bedrock. The results of the study have shown that the zones of low resistivity correspond to the zones of the cavities identified in the boreholes at the test site, and that the 3-D electrical resistivity survey is very effective to detect underground cavities.

• Journal of The Geomorphological Association of Korea
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• v.19 no.2
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• pp.1-15
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• 2012

The formative ages and processes of five natural abandoned channels in three types in Korea are studied. The former meandering channel in Seongsandong, Uljin-gun was abandoned due to the neck-cutoff of incised meander, Wangpi River in approximately 2.5~2.6ka and the abandoned channel in Bulyeong Temple, Uljin-gun was formed by the neck-cutoff of Wangpi River in approximately 90ka. Deduced from these results, it is judged to favorable for formation of abandoned channels by incised meander cutoff in interglacial or interstadial stages that had a better condition for meander cutoff because of active lateral erosion. Due to the corrosion of limestone joints in the underground of ridges between Hwangji River and Cheolam River, the channel in Gumumso, Taebaek-si was abandoned by the stream piracy connecting and combining the rivers into a limestone cave in approximately 40ka and higher lower reaches of Dong River than Banbyeon River in Seonbawi, Yeongyang-gun was turned to the abandoned channel throughout the stream piracy between the rivers in approximately 1.4ka. During Last Glacial Maximum in Jangcheon-ri, Chungju-si, Namhan River was divided into the eastern and western tributaries due to the alluvial island in approximately 10ka and then the western tributary was abandoned recently.