• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2022년도 학술발표회
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• pp.275-275
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• 2022

Tsunamis triggered by undersea earthquakes have the characteristic of longer wavelengths and can propagate a very long distance. Although the occurrence frequency of tsunami is low, it can cause casualties and properties. Historically, tsunamis that occurred on the western coast of Japan attacked the eastern coast of the Korean Peninsula and damaged the property and the loss of human life in 1983 and 1993. By tsunami in 1983 especially, 2 people were killed, and more than 200 casualties occurred. In addition, it caused 2 million dollars in property damage at Imwon Port. In 2011, The eastern cities of Japan: Iwate, Miyagi, Ibaraki, and Fukushima were damaged by a tsunami that occurred near onshore along the Pacific ocean and caused more than 300 billion dollars in property damage, and 20,000 casualties occurred. Moreover, those provoked nuclear power plant meltdown at Fukushima. In this study, it was carried out a relationship between maximum tsunami heights and fault parameters of earthquake: strike angle, dip angle, and slip angle at Imwon port. Those fault parameters are known that it does not relate to the magnitude of earthquake directly. Virtual tsunamis, which could be triggered by probable undersea earthquakes in the future, were investigated and mutual information based on probability and information theory was introduced to figure out the relationship between maximum tsunami height and fault parameters. Fault parameters were evaluated according to the strong relationship with maximum tsunami heights finally.

• 지구물리와물리탐사
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• 제11권2호
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• pp.137-147
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• 2008

2007년 1월 20일 발생한 '오대산지진(M = 4.8)'의 특징적인 점은 근거리 지역 관측소인 DGY(기상청 대관령, 진앙거리 = 7 km)에서 기록된 비정상적으로 높은 PGA(최대지반가속도) 관측값(< 0.1 g)이다. 한편 DGY 관측소는 진앙지인근에 위치한 매우 양호한 지진관측소(연관희와 서정희, 2007)로 분류되므로 지진파전달이나 부지증폭특성으로는 설명될 수 없으며, 고주파지진동에 큰 영향을 주는 지진원 특성인 단층파열방향성(rupture directivity)에 의한 것으로 예비 해석될 수 있다. 이 연구에서는 Boatwright (2007)의 방법을 이용하여 단층파열속도(v)의 전단파속도(c)에 대한 상대적 비(= v/c) 및 파열진행방향과의 이격각(${\theta}$, deviation angle)에 대한 함수로 주어지는 일방향 단층파열방향성(unilateral rupture directivity)을 추정하였다. 이러한 단층파열방향성을 평가하기 위해 진앙지 인근 지역의 지진관측소에 대한 점지진원 스펙트럼 모델(Boore, 2003)에 대한 예측오차를 오대산지진의 전 여진 관측자료을 이용하여 계산한 후, 본진 관측자료를 이용한 예측오차와 상대적으로 비교하였다. 본진의 전 여진에 대한 상대적인 스펙트럼 예측오차로부터 관측소별 PGA의 상대적인 크기를 추정하고 이 결과를 이용하여 오대산지진의 단층파열 방향성을 평가한 결과, 오대산지진 인근에서의 높은 PGA 관측값은 NWW-SEE 방향의 북측으로 고각을 갖는 단층면상에서 SE 방향을 따라 거의 수직하게 지표면으로 빠르게 진행된 단층파열의 영향으로 해석되었다.

• Geomechanics and Engineering
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• 제37권2호
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• pp.189-195
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• 2024

Buried pipelines can be classified as continuous and segmented pipelines. These infrastructures can be damaged either by ground movement or by seismic wave propagation during an earthquake. Permanent ground deformations (PGD) include surface faulting, liquefaction-induced lateral spreading and landslide. Liquefaction is a major problem for both superstructures and infrastructures. Buyukcekmece lake zone, which is the studied region in this paper, is a liquefaction prone area located near the North Anatolian Fault Line. It is an active fault line in Turkey and a major earthquake with a magnitude of around 7.5 is expected in this investigated region in Istanbul. It is planned to be constructed a new 12" steel natural gas pipeline from one side of the lake to the other side. In this study, this case has been examined in terms of two different support conditions. Firstly, it has been defined as a beam in liquefied soil and has built-in supports at both ends. In the other approach, this case has been modeled as a beam in liquefied soil and has vertical elastic pinned supports at both ends. These models have been examined and some solution proposals have been produced according to the obtained results. In this study, based on this sample, it is aimed to determine the behaviors of buried continuous pipelines subject to liquefaction effects in terms of buoyancy.

• Steel and Composite Structures
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• 제27권6호
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• pp.703-716
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• 2018

In this study, the different energy demands in reinforced concrete (RC) wall piers, coupled by buckling restrained braces (BRBs), are investigated. As well as this, a single plastic hinge approach (SPH) and an extended plastic hinge (EPH) approach is considered for the wall piers. In the SPH approach, plasticity can extend only in the 0.1H adjacent to the wall base while, in the EPH approach, the plasticity can extend anywhere in the wall. The seismic behavior of 10-, 20- and 30-storey structures, subjected to near-fault (NF) as well as far-fault (FF) earthquakes, is studied with respect to the energy concepts involved in each storey. Different kinds of energy, including inelastic, damping, kinetic, elastic and total input energy demand, are investigated. The energy contribution from the wall piers, as well as the BRBs in each model, are studied. On average, for EPH approach, the inelastic demand portion pertaining to the BRBs for NF and FF records, is more than 60 and 80%, respectively. In the SPH approach, these ratios are 77 and 90% for the NF and FF events, respectively. It appears that utilizing the BRBs as energy dissipation members between two wall piers is an efficient concept.

• 한국시스템다이내믹스연구
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• 제7권1호
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• pp.213-228
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• 2006

This paper reports the results of a study designed to understand and facilitate disaster mitigation for communities located in low frequency/high magnitude earthquake zones. The study is based on a small town located near the New Madrid Fault Zone and is therefore at significant earthquake risk. A system dynamics model describes the variables and policies governing the distribution of building safety over time. Data from this town is used to establish a 25-year baseline. Simulations are run to demonstrate the consequences of different building policies.

• 한국지구과학회지
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• 제38권7호
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• pp.561-569
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• 2017

2015년 12월 22일 전북 익산시 북쪽 지역에서 발생한 익산지진($M_L=3.85$)의 본진 및 2개 여진에 대해 FOCMEC (FOCal MEChanism determination) 프로그램을 이용하여 단층면해를 구하였다. 본진의 단층면해는 북동-남서 또는 북서-남동 방향의 단층면을 가지는 역단층성 주향이동단층운동의 특성을 보이며, 이는 남한 내륙지진의 단층운동 특성과 거의 유사하다. 익산지진 전후 발생한 미소지진 이벤트를 검출하고자 2015년 12월 15일~2016년 01월 22일 진앙으로부터 반경 100 km 이내에 위치한 13개 관측소에 기록된 연속 지진파형 자료를 PQLII 프로그램(PASSCAL, 2017)으로 분석하고, 19개 지진의 진원지를 새로 결정하였다. 미소지진의 진앙 분포는 특정 단층 혹은 구조선에 집중되는 현상은 나타나지 않았으나, 익산지진과 3개의 여진은 한곳에 집중 분포한다. 익산지진의 진도 분포는 전화 문의 및 피해 접수 자료를 수집하여 구하였으며, 또한, 각 관측소에 기록된 PGA (Peak Ground Acceleration)를 이용하여 계기진도를 도출하였다. 그 결과 익산지진의 MMI 진도등급은 최대 V로 평가된다.

• Steel and Composite Structures
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• 제1권1호
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• pp.145-158
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• 2001

An experimental study was conducted to evaluate the effects of loading sequence and lateral bracing on the behavior of reduced beam section (RBS) steel moment frame connections. Four full-scale moment connections were cyclically tested-two with a standard loading history and the other two with a near-fault loading history. All specimens reached at least 0.03 radian of plastic rotation without brittle fracture of the beam flange groove welds. Two specimens tested with the nearfault loading protocol reached at least 0.05 radian of plastic rotation, and both experienced smaller buckling amplitudes at comparable drift levels. Energy dissipation capacities were insensitive to the types of loading protocol used. Adding a lateral bracing near the RBS region produced a higher plastic rotation; the strength degradation and buckling amplitude were reduced. A non-linear finite element analysis of a one-and-a-half-bay beam-column subassembly was also conducted to study the system restraint effect. The study showed that the axial restraint of the beam could significantly reduce the strength degradation and buckling amplitude at higher deformation levels.

• 한국지구과학회지
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• 제28권2호
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• pp.202-213
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• 2007

2007년 1월 20일 평창군 진부면 오대산 일대에서 발생한 오대산 지진$(M_L=4.8)$은 천발지진(진원깊이 약 10 km)으로서 감진구역이 남한 남서부 일부를 제외한 전역에 이르렀다. 본진에 의한 최대 진도는 VI으로 VI에 해당하는 지역은 평창군 진부면, 도암면, 강릉, 주문진, 평창을 포함하는 지역으로서 강한 지진동과 함께 건물 실내외부 벽의 균열발생, 지붕의 기와나 스레트의 낙하 및 이동, 실내외 벽 타일의 떨어짐, 선반위 물체의 떨어짐, 도로의 낙석 등이 발생하였다. P파 초동극성과 SH/P 진폭비 자료를 이용한 단층면해는 본진의 경우 북북동-남남서 주향의 주향이동 단층운동을 나타내며, 2회의 여진은 남북 내지 북북동-남남서 주향의 역단층 운동이 우세함을 보인다. 전진, 본진 및 여진의 분포, 피해 지역 분포, 단층면해 등을 종합적으로 고려할 때 진앙지 부근에 우세하게 발달하고 있는 북북동-남남서 주향의 월정사단층이 기진 단층의 역할을 했을 것으로 추정된다. 여진 분포로 짐작컨대 subsurface에서의 이 단층의 파쇄 길이는 약 2 km로 판단되며, 추후 이 단층에 대한 고지진학적 조사가 필요하다.

• Smart Structures and Systems
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• 제22권4호
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• pp.383-397
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• 2018

Traditional base isolation systems focus on isolating the seismic response of a structure in the horizontal direction. However, in regions where the vertical earthquake excitation is significant (such as near-fault region), a traditional base-isolated building exhibits a significant vertical vibration. To eliminate this shortcoming, a rocking-isolated system named Telescopic Column (TC) is proposed in this paper. Detailed rocking and isolation mechanism of the TC system is presented. The seismic performance of the TC is compared with the traditional elastomeric bearing (EB) and friction pendulum (FP) base-isolated systems. A 4-storey reinforced concrete moment-resisting frame (RC-MRF) is selected as the reference superstructure. The seismic response of the reference superstructure in terms of column axial forces, base shears, floor accelerations, inter-storey drift ratios (IDR) and collapse margin ratios (CMRs) are evaluated using OpenSees. The results of the nonlinear dynamic analysis subjected to multi-directional earthquake excitations show that the superstructure equipped with the newly proposed TC is more resilient and exhibits a superior response with higher margin of safety against collapse when compared with the same superstructure with the traditional base-isolation (BI) system.

• Earthquakes and Structures
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• 제15권4호
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• pp.395-402
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• 2018

Floor location of adjacent buildings may be different in terms of height elevation, and thus, the slab may hit on the columns of adjacent insufficiently separated buildings during severe ground motions. Such impacts, often referred to as mid-column pounding, can be catastrophic. Substantial pounding damage or even total collapse of structures was often observed in large amount of adjacent low rise buildings. The research on the mid-column pounding between low rise buildings is in urgency need. In present study, the responses of two adjacent low rise buildings with unequal heights and different dynamic properties have been analyzed. Parametric studies have also been conducted to assess the influence of story height difference, gap distance and input direction of ground motion on the effect of structural pounding response. Another emphasis of this study is to analyze the near-fault effect, which is important for the structures located in the near-fault area. The analysis results show that collisions exhibit significant influence on the local shear force response of the column suffering impact. Because of asymmetric configuration of systems, the structural seismic behavior is distinct by varying the incident directions of the ground motions. Results also show that near-fault earthquakes induced ground motions can cause more significant effect on the pounding responses.