• Title/Summary/Keyword: Geological Hazard

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Researches Related to Seismic Hazard Mitigation in Taiwan

  • Loh, Chin-Hsiung;Yeh, Chin-Hsun
    • Journal of the Earthquake Engineering Society of Korea
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    • v.2 no.3
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    • pp.13-26
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    • 1998
  • In view of the rapid development of economics and technology, perilous meteorological and geological conditions often cause natural disasters and result in severe loss of lives and properties in Taiwan. To promote multi-hazard mitigation strategies in an integrated a, pp.oach, the National Science Council established a National Science and Technology Program for Disaster Mitigation in January 1998. This program emphasizes on the implementation of research results in the National Disaster Management System. This paper describes the earthquake loss estimation methodology that is currently developed in Taiwan. Topics of potential earth science hazards (PESH) and building vulnerability analysis are described in detail.

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Analysis of Slope Hazard Probability around Jinjeon-saji Area located in Stone Relics (석조문화재가 위치한 진전사지 주변의 사면재해 가능성 분석)

  • Kim, Kyeong-Su;Song, Young-Suk;Cho, Yong-Chan;Jeong, Gyo-Cheol
    • The Journal of Engineering Geology
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    • v.18 no.3
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    • pp.303-309
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    • 2008
  • A probability of slope hazards was predicted at a natural terrain around the stone relics of Jinjeon-saji area, which is located in Yangyang, Kangwon Province. As the analyzing results of field investigation, laboratory test and geology and geomorphology data, the effect factors of landslides occurrence were evaluated. Also, the landslides prediction map was made up using the prediction model by the effect factors. The landslide susceptibility of stone relics was investigated as the grading classification of occurrence probability. In the landslides prediction map, the high probability area was $3,489m^2$ and it was 10.1% of total prediction area. The high probability area has over 70% of occurrence probability. If landslides are occurred at the predicted area, the three stories stone pagoda of Jinjeon-saji(National treasure No. 122) and the stone lantern of Jinjeon-saji(Treasure No.439) will be collapsed by debris flow.

A GIS-based Environmental Sensitivity Assessment of Geopark - Slope Disaster in Cheongsong UNESCO Global Geopark - (GIS를 활용한 지오파크 환경 민감성 평가 - 청송 세계지질공원의 사면재해 민감성을 중심으로 -)

  • Kim, Hyejin;Sung, Hyo Hyun;Kim, Jisoo;Ahn, Sejin
    • Journal of The Geomorphological Association of Korea
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    • v.27 no.2
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    • pp.81-97
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    • 2020
  • Geopark refers to a single boundary area consisting of a collection of geosites and geotrails, which includes ecological, historical and cultural elements based on geological and geomorphological resources. To ensure the continued development and conservation of existing listed geoparks, it is necessary to carry out an environmental sensitivity analysis of the geopark components by utilizing spatial information from various scales. The objectives of this study are to analyze the environmental sensitivity in Cheongsong UNESCO global geopark in relation with slope disaster using GIS and to understand its spatial distribution in connection with geosites and geotrails. Two types of spatial database were constructed; geosites and geotrails in Cheongsong UNESCO global geopark and spatial data to perform environmental sensitivity. Potential soil loss and slope stability were analyzed to derive environmental sensitivity related to slope hazard. The results showed relatively high environmental sensitivity along the drainage network of Cheongsong UNESCO global geopark. Zonal statistics analysis was conducted for further detailed distribution of environmental sensitivity based on buffer zones of geosites and geotrails. Majority of geological sites, geological trails, Jeolgol gorge~Jusan Pond section in hiking trails, and Dalgi Mineral Spring Site~Artistic Genius Republic of Korea(Jangnankki gonghwaguk) section in road areas show relatively high slope hazard sensitivity within buffer zones.

Application of Spatial Data Integration Based on the Likelihood Ratio Function nad Bayesian Rule for Landslide Hazard Mapping (우도비 함수와 베이지안 결합을 이용한 공간통합의 산사태 취약성 분석에의 적용)

  • Chi, Kwang-Hoon;Chung, Chang-Jo F.;Kwon, Byung-Doo;Park, No-Wook
    • Journal of the Korean earth science society
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    • v.24 no.5
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    • pp.428-439
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    • 2003
  • Landslides, as a geological hazard, have caused extensive damage to property and sometimes result in loss of life. Thus, it is necessary to assess vulnerable areas for future possible landslides in order to mitigate the damage they cause. For this purpose, spatial data integration has been developed and applied to landslide hazard mapping. Among various models, this paper investigates and discusses the effectiveness of the Bayesian spatial data integration approach to landslide hazard mapping. In this study, several data sets related to landslide occurrences in Jangheung, Korea were constructed using GIS and then digitally represented using the likelihood ratio function. By computing the likelihood ratio, we obtained quantitative relationships between input data and landslide occurrences. The likelihood ratio functions were combined using the Bayesian combination rule. In order for predicted results to provide meaningful interpretations with respect to future landslides, we carried out validation based on the spatial partitioning of the landslide distribution. As a result, the Bayesian approach based on a likelihood ratio function can effectively integrate various spatial data for landslide hazard mapping, and it is expected that some suggestions in this study will be helpful to further applications including integration and interpretation stages in order to obtain a decision-support layer.

A Study on mine drainage characteristcs as abandoned Coal mine in Gyeongsang province (경상도 일대의 폐탄광 갱내수의 수질 특성 연구)

  • Jung, Young-Kook;Hong, Ji-Hye;Lee, Dong-Jin;Kim, Jeong-Phill;Kim, Dae-Gi;Joo, Sang-Don
    • Proceedings of the Korean Geotechical Society Conference
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    • 2008.10a
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    • pp.1440-1445
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    • 2008
  • There are 21 abondoned coal mines drained out mine water in gyeong sang do. We monitored the water quality of 31 mine drainage from 1995. The most of mine drainage was neutral as the average pH was 6.22 and Fe, Mn, Al concentration was below 10mg/L. The result showed the tendency of decreasing of flow and metal concentration. The highest Mn concentration was detected in bonghwa area and the hightest Fe concentration was detected in munkyung area. It means that the water quality is closly related to geological features.

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A Note on the Earthquake Double Counting (지진의 이중산입에 대한 소고(小考))

  • Noh, Myunghyun
    • Journal of the Earthquake Engineering Society of Korea
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    • v.27 no.3
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    • pp.157-162
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    • 2023
  • As a result of active geological investigation of faults in Korea, many Quaternary faults have been identified and some of them were judged to have potential to generate earthquakes. Those faults need to be considered as additional seismic sources in the seismic hazard analysis. When a fault is introduced as a new source, the earthquakes generated by the fault should be removed from the area sources that include any part of the fault, to avoid double counting. In practice, however, double counting cannot completely be avoided as the complete separation of the fault-generated earthquakes from the area sources is impossible due to uncertainties related to the earthquake location, subsurface structures of faults, etc. When a new fault source is introduced, the only constraint is the invariance of earthquake frequency. The maximum earthquake and the Richter-b value should also be subject to change, but there are no competent approaches to estimate the change due to incomplete separation of earthquakes. To gain insight into the effect of a new fault source, an example calculation of the seismic hazard were carried out. The example calculation shows that addition of a new fault source centers seismic hazard around the fault source.

Preparation of Landslide Hazard Map Using the Analysis of Historical Data and GIS Method (GIS 기법 및 발생자료 분석을 이용한 산사태 위험지도 작성)

  • Yun, Hong-Sik;Lee, Dong-Ha;Suh, Yong-Cheol
    • Journal of the Korean Association of Geographic Information Studies
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    • v.12 no.4
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    • pp.59-73
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    • 2009
  • In this study, we performed a GIS-based landslide hazard analysis by employing historical landslide data in Korea, coupling with geomorphological, geological, climatic and rainfall data. Based on 596 landslide data from 2001 to 2003, the correlations between landslide occurrence and various factors (elevation, slope angle, slope aspect, soil type and rainfall) that affect the occurrence were estimated by the statistical analysis, zonal statistics. The weights and hazard indices of 6 raster layers were derived from the estimated correlations in order to generate a landslide hazard map by applying raster calculation technique. As a result of this study, GIS technique can be used effectively to incorporate the landslide hazard contributions from various data sets simultaneously.

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Analysis of Slope Stability by Using Remote Sensing and GIS Around Chungju Area (원격탐사와 지구정보시스템을 이용한 충주지역의 사면안정분석)

  • Shin, Hyunjun;Lee, Younghoon;Min, Kyungduck;Won, Joongsun;Kim, Younjong
    • Economic and Environmental Geology
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    • v.29 no.5
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    • pp.615-622
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    • 1996
  • Slope stability analysis was conducted using remote sensing and Geoscientific Information System (GIS) as a part of natural hazard assessment around Chungju area. Landsat TM band 5 and 7 which contain more information about geological structure and geography are chosen and processed to analyse regional geological structure. Through image processing technique such as PCA, HFF, edge detection and enhancement, regional lineament can be mapped and identified. The lineament density map is constructed based on summed length of lineaments per unit area and the study area can be divided into 7 structural domains. Various factors of slope stability analysis such as geology, slope aspect, degree of slope, landcover, water shed as well as characterized structural domain are constructed as a database of GIS. Rating and weighting of each factor for slope stability analysis is decided by considering environmental geological characteristics of study area. Spatial analysis of regional slope stability is examined through overlaying technique of the GIS. The result of areal distribution of slope stability shows that the most unstable area is all over Jaeogae-ni, Hyangsan-ni and Mt. Daedun.

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A Structure-controlled Model for Hot Spring Exploration in Taiwan by Remote Sensing

  • Liu, Jin-King;Yu, Ming-Fang;Ueng, Shiun-Jenq
    • Proceedings of the KSRS Conference
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    • 2003.11a
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    • pp.28-30
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    • 2003
  • Hot Spring Law of Taiwan was passed in legislative assembly on 3 June 2003. Hot springs would become one of the most important natural resources for recreation purposes. Both public and private sectors will invest large amount of capital in this area in the near future. The value of remote sensing technology is to give a critical tool for observing the landscape to find out mega-scaled geological structures, which may not be able to be found by conventional approaches. The occurrences of the hot springs in Taiwan are mostly in metamorphic and sedimentary rocks , other than in volcanic environments. Local geothermal anomaly or heat of springs transfer by liquid convection other than conduction or radiation. The deeply -seated fractures of hard rocks are the conduit of the convection of hot water, which could be as deep as 3000 meters in a hypothetical model of Taiwan. Clues to find outcrops of hot spring can be obtained by a structure-controlled model deduced by geological lineaments observed by satellite images and stereoscopic interpretation of aerial photographs. A case study conducted in Eastern Taiwan will be demonstrated.

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The History of Volcanic Hazard Map (화산위험지도의 역사)

  • Yun, Sung-Hyo;Chang, Cheolwoo;Ewert, John W.
    • The Journal of the Petrological Society of Korea
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    • v.27 no.1
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    • pp.49-66
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    • 2018
  • Volcano hazard mapping became a focus of scientific inquiry in the 1960s. Dwight Crandell and Don Mullineaux pioneered the geologic history approach with the concept of the past is the key to the future, to hazard mapping. The 1978 publication of the Mount St. Helens hazards assessment and forecast of an eruption in the near future, followed by the large eruption in 1980 demonstrated the utility of volcano hazards assessments and triggered huge growth in this area of volcano science. Numerical models of hazardous processes began to be developed and used for identifying hazardous areas in 1980s and have proliferated since the late 1990s. Model outputs are most useful and accurate when they are constrained by geological knowledge of the volcano. Volcanic Hazard maps can be broadly categorized into those that portray long-term unconditional volcanic hazards-maps showing all areas with some degree of hazard and those that are developed during an unrest or eruption crisis and take into account current monitoring, observation, and forecast information.