Definition and classification of fault damage zones: A review and a new methodological approach

Choi, J.H.,Edwards, P.,Ko, K.,Kim, Y.S. Elsevier Pub. Co 2016 Earth-science reviews Vol.152 No.-

<P>Although the widths of fault damage zones commonly show a positive correlation with displacements, these relationships also show a somewhat scattered distribution. We believe that one of the fundamental reasons for this problem is strongly related to subjective definitions and inconsistent uses of the term 'damage zone'. Thus, firstly we classify damage zones into along-fault, around-tip and cross-fault damage zones based on descriptive views of an arbitrary fault exposure as well as their tridimensional locations around a segmented fault system. Secondly, we propose an advanced field technique and data acquisition method to more accurately define a damage zone using the distribution of cumulative fracture frequency. We tested this method on new field and borehole observations as well as previously published data to identify damage zone boundaries, and express them as a change in slope gradients of the cumulative distribution of deformation structures. The results show how this slope change can be a useful criterion in accurately defining the width of damage zones and some internal properties of fault zones. We argue that this damage zone classification and definition method should be adopted and used to prevent discrepancies in field data. This will help us to gain a better understanding of fault damage zone properties and their scaling with fault displacement. (C) 2015 Elsevier B.V. All rights reserved.</P>

Inferred fluid flow through fault damage zones based on the observation of stalactites in carbonate caves

Kim, Y.S.,Sanderson, D.J. Pergamon Press 2010 Journal of structural geology Vol.32 No.9

Faults and fractures are important factors that control fluid flow in rock masses in hydrothermal, groundwater, and hydrocarbon systems. In this paper we examine local variations in fluid flow as evidenced by the distribution patterns and sizes of stalactites in fractured limestone. We observe that the size and distribution of stalactites relate to fluid flow and is strongly controlled by the fracture apertures, intersection of fractures, and development of damage zones around a fault. Fault damage zones are the volumes of deformed wall rocks around a fault surface that result from the initiation, propagation, interaction, termination, and build-up of slip along the fault. They are divided into tip-, wall-, and linkage damage zones depending on their location along the fault. The pattern of deformation within a damage zone mainly depends on fault tip modes (mode II or III), the 3-D locations around a fault surface, and the evolutionary stage of the fault. The development of different structures within damage zones gives valuable information about fault initiation and termination, fault propagation and growth, and fluid flow. Stalactites indicate fluid flow variation within a fault in that fluid flow is high in dilational jogs, variable along the main fault traces, and low in contractional jogs. Variation in ore fluid flow within faults is also important in controlling the position of ore shoots in structurally-controlled hydrothermal mineral deposits. Thus, the characteristics of fluid flow in fractured carbonate rocks can be related to patterns of damage around faults. Hence, the mapping of damage zones can be applied to the study of fracture-controlled fluid flow in the fields of petroleum geology, hydrogeology, and ore deposits.

경주 남산 일대의 단열구조 특성과 양산단층의 분절

김헌주 ( Heon Joo Kim ),장태우 ( Tae Woo Chang ) 대한지질공학회 2009 지질공학 Vol.19 No.1

경주시 남산 일대에서 양산단층의 활동에 수반된 단열 특성과 양산단층의 분절에 관한 연구가 수행되었다. 절리의 밀도와 프랙탈 차원 값은 양산단층에 가까워질수록 높은 값을 보이는데 이는 단층활동에 따른 단열작용이 단층의 중심에서 더 격렬하게 일어난 탓으로 해석할 수 있다. 양산단층 손상대와 모암 사이의 경계는 단층의 중심에서 약 2.7 km까지로 볼 수 있으며 여기서 더 멀어지면 절리밀도와 프랙탈 차원 값이 현저히 감소하고 절리의 배향도 여러 방향으로 크게 분산된다. 양산단층 손상대 내 소단층들은 우수향이동단층과 좌수향이동단층들로 뚜렷이 구분되는데, 전자는 양산단층이 우수향이동을 할 때 수반된 단층들이고 후자는 좌수향이동 운동 시에 수반된 것들로 간주된다. 연구지역에서 양산단층은 북쪽분절과 남쪽분절로 나누어 질 수 있는데 이는 북쪽분절과 남쪽분절 간 주향의 차이, 북쪽분절 끝부분에서 압축성 인편팬기하 와 9o, S85oE로 선경사하는 향사의 발달, 남쪽분절 끝부분에서 28o, N4oW로 선경사하는 배사의 발달 등의 증거에 의해 뒷 밭침 할 수 있다. Fractures and segmentation in association with the activities of the Yangsan fault are studied around Mt. Namsan, Gyengju city in the southeastern part of Korea. It is believed that the higher values of joint density and fractal dimension with the approach of the center of the Yangsan fault mean intense fracturing due to the fault activity. The boundary between fault damage zone and host rock is inferred to be placed at about 2.7 km from the center of the Yangsan fault where the values of joint density and fractal dimension abruptly decrease and the orientations of joint are also much dispersed. The small faults within the damage zone of the Yangsan fault are definitely divided into right-lateral and left-lateral strike-slip faults. The former is considered to be formed during the right-lateral movement of the Yangsan fault and the latter during the left-lateral movement. The Yangsan fault is segmented in the study area with obvious evidences as follows: (1) the difference of fault strike between northern and southern segments, (2) The geometry of contractional imbricate fans and syncline plunging 9o, S85oE at the end of northern segment, and (3) anticline plunging 28o, N4oW at the end of southern segment.

양산단층 북부 일대의 최후기 지구조환경에 대해

류충렬(Chung-Ryul Ryoo),강지훈(Ji-Hoon Kang),강희철(Hee-Cheol Kang) 한국암석학회 2018 암석학회지 Vol.27 No.3

한반도 동남부에 발달하는 중생대 백악기의 경상분지를 변형시키는 최후기의 구조들은 주로 양산단층대를 따라 발달하며, 양산단층대의 북부에서는 보경사와 단구리 사이에서 주로 관찰된다. 이러한 구조들은 양산단층 뿐만 아니라 그 주변에서도 유사한 기하와 운동학적인 양상을 보이며 관찰되고 있다. 대체로 남-북 내지 북동 방향의 단열 또는 지형지구조선의 동측이 서쪽이나 북서쪽으로 올라탄 운동을 보이며, 주로 북서 방향의 단열 또는 지형지구조선들을 따라 주향이동성운동을 하며 보조단층의 역할을 한 것으로 해석된다. 양산단층대 북부 지역의 역단층들은 대부분 서쪽으로 볼록한 선상구조를 보이는 특징을 가지는데, 이들은 아마도 북서-남동 방향으로의 인장 시기에 형성된 정단층들이 후기에 동-서 방향의 압축에 의해 재활동한 것으로 사료된다. 이러한 특징은 포항-흥해 일대의 지형지구조 분석에서도 비슷한 양상으로 나타나며, 11.15 포항지진과 관련된 지표단열들의 발생과 심한 피해지역의 분포와 구조적 연관성을 가지는 것으로 보인다. Geologic structures related to the latest event in the evolution around Gyeongsang Basin are mainly associated with the Yangsan Fault. In particular, the structures in the northern part of the Yangsan Fault are mainly observed in the region between Bogyeongsa Temple and Danguri. Such structures are also clustered in the vicinity of the Yangsan Fault, exhibiting similar geometric and kinematic patterns. In general, N-S and NE-SW trending fractures and tectonogeomorphic lineament are mainly eastward dipping reverse faults, such that the blocks in the east of the structures moved west or northwest. The reverse faults are segmented by NW trending fractures that accommodate strike-slip movements. The reverse faults and geomorphotectonic lineaments related to the latest event of deformation in the northern part of the Yangsan Fault show a westward convex patterns. We infer that these structures were initially normal faults that formed during a NW-SE extensional environment and were later reactivated during an E-W compressional one. Such a deformation pattern is also well developed around Pohang-Heunghae area based on the tectonogeomorphic analysis, which appears to be closely related to the Pohang Earthquake (15 Nov. 2017), and its development of the surface rupture and highly damaged zones.

원자력시설물 부지의 장기적 안전성 확보를 위한 지질구조 평가

진광민(Kwang min Jin),김영석(Young Seog Kim) 대한자원환경지질학회 2018 자원환경지질 Vol.51 No.2

전 세계적으로 대규모 지진의 발생과 이로 인한 인명피해와 재산피해는 끊임없이 발생하고 있다. 특히 일본의 동일본 대지진(M=9.0; 2011. 3. 11.)은 이로 인한 쓰나미의 발생으로 상당한 인명피해와 경제적 손실을 가져왔고, 후쿠시마 원전사고를 유발하였다. 대부분의 지진은 기존 활성단층들의 재활성에 의해 발생한다. 따라서 활성단층에 의한 지진의 재발특성을 이해하기 위한 고지진학적 연구가 활발히 수행되고 있다. 우리나라는 유라시아판 내부에 위치하여 이웃한 일본이나 대만과 같은 나라들에 비해 지진으로부터 안전지대로 여겨져 왔다. 그러나 최근 경주지진(M=5.8; 2016. 9. 12.)과 포항지진(M=5.4; 2017, 11. 15.)으로 인해 우리나라에서도 지진재해에 대한 불안감이 증가하고 있다. 특히 이 지역은 많은 원자력관련 시설물들과 대규모 산업단지가 밀집되어 있는 지역들로 지진재해로부터 극도의 안전성이 확보되어야 한다. 그러나 한반도 남동부의 경우 대규모 지진들이 제4기뿐만 아니라 역사시대에도 자주 발생한 것으로 보고되고 있다. 따라서 지진에 의한 피해를 줄이기 위해서는 활성단층을 추적하고, 활성단층을 따른 지표파열의 특성을 파악하여 해당지역에서의 지진과 단층의 거동특성을 이해하는 것이 중요하다. 이 연구에서는 극도의 안전성 확보가 필요한 원자력관련시설물들의 부지 선정을 위한 활성단층, 단층손상대, 지진과 활성단층의 상관성, 그리고 이격거리 등의 구조지질학적 평가방법을 설명하고, 이를 통해 안전한 원자력관련 시설물의 부지선정뿐만 아니라 지진재해와 방재에 유용한 정보를 제공하고자 한다. Many large earthquakes have continuously been reported and resulted in significant human casualties and extensive damages to properties globally. The accident of Fukushima nuclear power plant in Japan was caused by a mega-tsunami, which is a secondary effect associated with the Tohoku large earthquake (M=9.0, 2011. 3. 11.). Most earthquakes occur by reactivation of pre-existing active faults. Therefore, the importance of paleoseismological study have greatly been increased. The Korean peninsula has generally been considered to be a tectonically stable region compared with neighboring countries such as Japan and Taiwan, because it is located on the margin of the Eurasian intra-continental region. However, the recent earthquakes in Gyeongju and Pohang have brought considerable insecurity on earthquake hazard. In particular, this region should be secure against earthquake, because many nuclear facilties and large industrial facilities are located in this area. However, some large earthquakes have been reported in historic documents and also several active faults have been reported in southeast Korea. This study explains the evaluation methods of geological structures on active fault, fault damage zone, the relationship between earthquake and active fault, and respect distance. This study can contribute to selection of safe locations for nuclear facilities and to earthquake hazards and disaster prevention.

Important Parameters Related With Fault for Site Investigation of HLW Geological Disposal

진광민,김유홍,서동익,김영석 한국방사성폐기물학회 2021 방사성폐기물학회지 Vol.19 No.4

Large earthquakes with (MW > ~ 6) result in ground shaking, surface ruptures, and permanent deformation with displacement. The earthquakes would damage important facilities and infrastructure such as large industrial establishments, nuclear power plants, and waste disposal sites. In particular, earthquake ruptures associated with large earthquakes can affect geological and engineered barriers such as deep geological repositories that are used for storing hazardous radioactive wastes. Earthquake-driven faults and surface ruptures exhibit various fault zone structural characteristics such as direction of earthquake propagation and rupture and asymmetric displacement patterns. Therefore, estimating the respect distances and hazardous areas has been challenging. We propose that considering multiple parameters, such as fault types, distribution, scale, activity, linkage patterns, damage zones, and respect distances, enable accurate identification of the sites for deep geological repositories and important facilities. This information would enable earthquake hazard assessment and lower earthquakeresulted hazards in potential earthquake-prone areas.

Fault zone classification and structural characteristics of the southern Yangsan fault in the Sangcheon-ri area, SE Korea

최진혁(Jin-Hyuck Choi),양석준(Seok-Jun Yang),김영석(Young-Seog Kim) 대한지질학회 2009 지질학회지 Vol.45 No.1

Space-time patterns of fault activity of the Keumwang Fault developed in the Jincheon-Eumseong-gun, Chungcheongbuk-do

배한경(Han-Kyung Bae),이희권(Hee-Kwon Lee) 대한지질학회 2014 지질학회지 Vol.50 No.6

Structural features across a fault zone of the Baehuryeng fault at Chuncheon

이희권(Hee-Kwon Lee),이정국(Jong-Kuk Lee) 대한지질학회 2011 지질학회지 Vol.47 No.4

양산단층과 동래단층 사이를 통과하는 지방도의 지질공학적 특성 연구

이병주 ( Byung Joo Lee ),선우춘 ( Woo Choon Sun ) 대한지질공학회 2003 지질공학 Vol.13 No.2