대지진에 의한 건축물의 재해 패턴 분석

신상화,김진,박강근 한국주거환경학회 2018 주거환경(한국주거환경학회논문집) Vol.16 No.2

An earthquake is the shaking of the surface of the Earth, resulting from the sudden release of energy in the Earth's lithosphere that creates seismic waves. There are three main types of fault, all of which may cause a plate earthquake by normal, reverse and strike-slip. Many earthquakes are caused by movement on faults that have components of both dip-slip and strike-slip that is known as oblique slip. Many earthquakes occur away from the plate boundary and are related to strains developed within the broader zone of deformation caused by major irregularities in the fault trace. Earthquakes often occur in volcanic regions and are caused there, both by tectonic faults and the movement of magma in volcanoes. A particularly dangerous form of slow earthquake is the tsunami earthquake caused by the slow propagation speed of some great earthquake. Since 1900, there have been 20 huge earthquakes (magnitude 7.0–9.0). Earthquakes that caused the greatest loss of life were deadly because of their proximity, where earthquakes often create tsunami that can devastate communities thousands of kilometers away. In order to the effective measures of earthquake disaster, the evaluation of earthquake disaster risk is indispensable. The huge earthquakes in Japan caused the tsunami and the radiation damage of nuclear power plants. The damages of buildings are the failure of columns, the crack of beams, the crack of walls, the failure of foundations, the overturning of structures, the fall off of exterior cladding, the fall of interior finish, etc. This study is to analysis the disaster pattern by huge earthquakes, and proposes the design method of improved building to resist earthquake. The effect of buildings on earthquakes is very complex, it difficult to consider all of them in seismic design. The authors think to find the solution of earthquake problems through analyzing damage patterns of buildings. 최근에 우리나라에서 발생한 경주 지진(2016년)과 포항 지진(2017년)으로 인하여 원자력 발전소, 고층 아파트, 조적식 주택 등의 건축물에 대한 지진 피해의 심각성을 인식하고 있다. 이러한 시기에 기존의 지진의 피해에 대한 재해 패턴을 보다 면밀히 분석하여 체계화함으로써 지진 발생 시에 피해를 최소화 할 수 있고 사회 전반에 대한 지진 대비 시스템을 구축할 수 있다. 본 연구에서는 기존의 지진에 대한 피해 상황 및 피해 패턴을 분석하고 피해가 심각한 건축물의 이유와 문제점들을 조사하고, 지진에 효과적으로 저항할 수 있는 건축물을 설계하기 위한 구조설계 개념을 제시하였다. 최근에 전 세계적으로 대지진의 발생회수가 점점 더 증가되고 있고 때문에 지진에 대해서 보다 잘 이해하여 보다 안전하고 경제적인 건축물의 설계가 매우 중요하다고 생각된다.

태풍 파랑과 지진을 연계한 케이슨식 방파제의 동적거동

윤현수,노병진,윤성규,강기천,Hyeonsu Yun,Byeongjin Roh,Seong-Kyu Yun,Gichun Kang 한국지반신소재학회 2024 한국지반신소재학회 논문집 Vol.23 No.1

Recently, the frequency and intensity of typhoon-induced wave loading are increasing due to changed marine environments such as climate change. In addition, frequent earthquakes are causing a lot of damage around the world, including in Japan, Chile, Haiti, China, and Indonesia. In Korea, damage from typhoons has also been increasing since the 2000s, and the frequency and intensity of earthquakes are also increasing. Korea is surrounded by sea on three sides, so typhoons can cause a lot of damage to coastal structures, and earthquakes also cause a lot of damage to coastal structures. As such, the frequency and intensity of typhoon-induced wave loading and earthquakes are increasing both domestically and internationally, but there is no research linking typhoons and earthquakes. Therefore, in this study, numerical analysis was performed for a total of four cases by linking typhoon waves and earthquakes to the caisson breakwater. Numerical analysis was performed by applying wave loads in Case 1 and seismic wave in Case 2, seismic wave after wave loads in Case 3, and wave loads after seismic wave in Case 4. As a result of the numerical analysis, it was confirmed that in Case 3 and Case 4, which linked a typhoon and earthquakes, the damage caused by each load increased compared to Case 1 and Case 2 because the load was applied while the existing ground strength was reduced. In addition, it was confirmed that the greatest damage occurred in Case 3, in which seismic wave were applied after the wave loads.

일본에서의 지진과 해일대응법체계

김치환 ( Chi Hwan Kim ) 고려대학교 법학연구원 2011 고려법학 Vol.0 No.60

It has been increasing recognition that we are not safe anymore from the earthquakes and tsunami. The number of earthquakes has increased gradually in Korea. In particular, scale of 7 in Fukuoka Area earthquake in 2005 suggests the possibility of strong earthquake in our country. Therefore, we must work in preparation for an earthquake and tsunami. To do this, it is necessary to look at the disaster prevention system of Japan legally. Japan has experienced a myriad of earthquakes and tsunami, while legal prevention systems have evolved. The paper points out that the earthquake response system of Japan has two features. The one is that the earthquakes are mainly governed in Japan, not tsunami. And the other is that research for the prediction of earthquakes is systematically being pushed. In general, earthquake prediction is impossible. Nonetheless, Japan has continued to make efforts to predict earthquakes. A study of earthquake prediction has been involved in the many relevant agencies, for examples, Japan Meteorological Agency, including Geospatial Information Authority of Japan, Universities etc. The paper argues that we also need to have such a joint research system. And there is nothing wrong with being prepared. It is necessary to build the earthquake and tsunami response system.

Seismic Response of Asymmetric Steel Isolated Structures Considering Vertical Component of Earthquakes

Faramarz Khoshnudian,Danoush Motamedi 대한토목학회 2013 KSCE JOURNAL OF CIVIL ENGINEERING Vol.17 No.6

The concept of isolated structure is to separate the structure from harmful effects of earthquakes by introducing bearing. Regarding earthquakes such as the Bam and Kobe records with relatively high vertical component amplitude, it is necessary to investigate the behavior of the base-isolated structures considering vertical component of the ground motions. For this purpose, a four-story building with different eccentricities supported on elastomeric isolators with different vibration periods and damping ratios as well as three different records is used to study the effects of vertical component of earthquakes on the seismic behavior of asymmetric steel isolated structures. A rubber isolator element is used to idealize the nonlinear behavior of the isolators and a linear elastic behavior is assumed for the superstructure. The results demonstrate the significant effect of the vertical component of earthquake on the responses of structure such as axial forces, local uplift of the columns, and overturning moment of the structure and shear force of beams. For the studied cases including vertical component of earthquakes increases the compressive axial force (more than 100%) in corner columns. In addition the vertical component of earthquake causes significantly augmentation of tensile axial force and therefore, it results local uplift phenomena in isolators. Ignoring the vertical component of earthquake with high vertical amplitude will result unacceptable estimation in beam shear force and for some cases this error reaches 100%. This error is more important while the eccentricity of structure is significant (30%). Overturning safety factor is reduced when the vertical component of earthquake was included and this effect is more significant under earthquakes with higher ratio of vertical to horizontal component of earthquake.

2010-2017년 부산지역의 미소 지진 예비 탐색

윤소헌,한종원,원덕희,강수영,유용규,김광희 한국지구과학회 2019 한국지구과학회지 Vol.40 No.3

Although the knowledge of current seismicity is a critical information for making and implementing effective earthquake-related policy, the detailed seismicity information of the metropolitan areas with high-population density has been largely underestimated due to the high-level of cultural noise and small earthquake magnitude. This study presents 12 earthquakes including 2 earthquakes previously known and 10 additional earthquakes occurred from 2010 to 2017 in Busan, but they were unreported by the Korea Meteorological Administration. Matched filter technique is used to detect micro-earthquakes. Although the epicenters of micro-earthquakes though present a distinguished linearity, a correlation with faults in the area is unknown. A repeated micro-seismicity suggests that there are subsurface structures responsible for observed events. If large earthquakes occur along the fault in Busan, they may cause catastrophic natural disasters. Given the fact that the recent earthquakes did not accompany any surface signatures, it is highly recommended that the current micro-seismicity be investigated, and updated seismicity information be incorporated into establishing active fault maps in Korea. 지진 관련 정책 입안과 수행에 우선적으로 고려되어야 할 정보가 지진 발생현황이지만, 대도시와 인구밀집 지역의 경우 높은 생활잡음으로 인해 작은 규모의 지진 발생을 정확히 인지하지 못하는 경우가 많다. 본 연구에서는 2010년부터 2017년까지 부산지역에서 발생했지만, 규모가 작아 기상청 지진목록에 수록되지 않은 미소 지진 10회를 파형의 유사성을 이용하여 검출하였고, 기존에 발생사실을 알고 있던 지진을 포함하여 총 12회의 지진을 분석에 사용하였다. 새로이 보고되는 지진은 선형을 보이면서 발생하고 있지만, 주변의 단층과 직접적으로 연관하여 해석하기에는 자료가 충분치 않다. 규모가 작은 미소 지진이 꾸준히 발생한다는 것은 지하에 지진을 일으키는 단층이 존재함을 시사하고, 부산과 같은 인구밀집 지역에서 과거 피해를 유발한 역사지진과 비슷한 규모의 지진이 발생한다면 대형 피해로 발전될 가능성이 매우 크다. 최근 우리나라에서 발생한 피해 유발 지진이 지표파열을 동반하지 않고 발생하고 있음을 고려할 때 현재 발생하고 있는 미소지진 현황을 파악하여 지표 단층조사와 함께 지하단층을 규명하는데 활용하여야 한다.

Depth-dependent seismicity and crustal heterogeneity in South Korea

Chung, Tae Woong,Iqbal, Muhammad Zafar,Lee, Youngmin,Yoshimoto, Kazuo,Jeong, Jina Elsevier 2018 Tectonophysics Vol.749 No.-

<P><B>Abstract</B></P> <P>Depth-dependent seismicity has been suggested in the seismogenic layer, which is divided into upper and lower layers by its seismicity boundary. Since large earthquakes tend to occur in the lower layer, the structure of the seismogenic layer, which includes the seismicity boundary, provides important information for seismic hazard assessment. Using 107 land-based earthquakes, the structure of the seismogenic layer in South Korea was studied with focal depth determination by identifying the minimum residuals between the observations and several models. The same procedure was done for the depth relocation of 138 events associated with the Gyeongju earthquake (M<SUB> <I>L</I> </SUB> 5.8), the largest event in South Korea in the last two centuries. The geothermal temperature at the focal depth was also estimated for all earthquakes, including the Gyeongju earthquake cluster and the Pohang earthquake (M<SUB> <I>L</I> </SUB> 5.4), which caused more damage than did the Gyeongju earthquake. As observed in a large-scale averaging of mainland China, a 12-km seismicity boundary was suggested due to the frequent seismicity in the upper layer. At 12-km depth at the Gyeongju earthquake site, the geothermal temperature reached 300 °C, and the occurrence of aftershocks was limited below that depth. Based on the rigorously estimated depth, we separated the scattering attenuation, <I>Q</I> <SUB> <I>s</I> </SUB> <SUP>−1</SUP>, by a multiple lapse time window analysis using individual earthquakes and found higher and lower values for events in the upper and lower layers, respectively. This depth-dependent observation suggests differences in heterogeneity between the upper and lower seismogenic layers and supports the hypothesis that the seismicity of a depth-dependent seismogenic layer is related to cracks, which diminish with depth. Our results suggest that the upper limit of the focal depth can be predicted from the depth of the seismicity boundary for normal large earthquakes.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The seismicity boundary of seismogenic layer in South Korea was identified. </LI> <LI> Crustal seismic-wave scattering strength exhibits depth-dependent heterogeneity between the two layers. </LI> <LI> The upper limit of the focal depth of large earthquakes can be predicted from the depth of the seismicity boundary. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Focal depths versus number of earthquakes for South Korea, and the Gyeongju earthquake cluster. The seismogenic layer (<I>S.L.</I>) consists of upper and lower layers divided at 12-km depth. The histograms with orange fill denote focal depth temperatures higher than 300 °C. Red and blue stars denote the ML 5.8 and 5.1 events, respectively. In the right graph, the scattering Q<SUP>−1</SUP> values with frequencies are shown as connected lines of events exclusively included in the upper and lower layers, respectively.</P> <P>[DISPLAY OMISSION]</P>

Investigation of the relationship between earthquakes and indoor radon concentrations at a building in Gyeongju, Korea

김재욱,주한영,김린아,문주현 한국원자력학회 2018 Nuclear Engineering and Technology Vol.50 No.3

This article measured and analyzed the indoor radon concentrations at one university building inGyeongju, Republic of Korea, to investigate if there is any relationship between earthquakes and indoorradon concentration. Since 12 September 2016, when two 5.1 and 5.8 magnitude earthquakes occurred,hundreds of aftershocks affected Gyeongju until January 2017. The measurements were made at theground floor of the Energy Engineering Hall of Dongguk University in Gyeongju over a period betweenFebruary 2016 and January 2017. The measurements were made with an RAD7 detector on the basis ofthe US Environmental Protection Agency measurement protocol. Each measurement was continuouslymade every 30 minutes over the measurement period every month. Among earthquakes with 2.0 orgreater magnitude, the earthquakes whose occurrence timings fell into the measurement periods werescreened for further analysis. We observed similar spike-like patterns between the indoor radon concentrationdistributions and earthquakes: a sudden increase in the peak indoor radon concentration 1e4days before an earthquake, gradual decrease before the earthquake, and sudden drop on the day of theearthquake if the interval between successive earthquakes was moderately longer, for example, 3 days inthis article.

메이지 일본의 지진 및 쓰나미를 둘러싼 과학, 국가, 문명

김범성 일본사학회 2012 일본역사연구 Vol.35 No.-

While earthquakes and tsunamis are natural phenomena, their impacts on humans include those of a social nature. In Meiji Japan, the meaning of disasters formed in the context of “modernization,” whose standard was European civilization, and was transformed in the matrices of international as well as domestic politics. In this context, this essay sketches out how discourses on science, state, and civilization interacted with disasters, particularly earthquakes and tsunamis. It should be noted that the Yokohama Earthquake of 1880 triggered scientific interest in seismicity. Although this earthquake’s damage was not catastrophic, since the European community and structures in the treaty port were more sensitive than Japanese varieties, foreign scientists discovered earthquakes in Japan, then a geophysical blank, as a topic of scientific research. This interest by the Europeans led to the development of seismographs, which could depict the motion of the ground graphically. On the other hand, the Meiji government absorbed the knowledge and knowledge production systems of the European scientists within the Ministry of Home Affairs and the Imperial University. In the aftermath of the Great Nobi Earthquake of 1891, recognizing earthquakes as “a menace to the construction of a modern state,” the government organized the Imperial Earthquake Investigation Committee. When catastrophic tsunami waves devastated the Sanriku coasts in 1896, governmental organizations served as frameworks to investigate the “national crisis.”However, just as seismic and tidal waves transcend political borders, knowledge of earthquakes was crossing the geopolitical hierarchy of “civilization.” The 1890s already saw the emergence of a discourse, “Japan is an advanced country in the field of seismology,” and this notion subsequently resonated in the English-speaking scientific world. In the decade of the Russo-Japanese War and the Yellow Peril, this discourse served as a means to display Japan as a member of the civilized world. Nevertheless, such advanced science was not a strong enough influence to overturn the established racial order of the time.

Disaster preparedness for earthquakes in hemodialysis units in Gyeongju and Pohang, South Korea

( Kyung Don Yoo ),( Hyo Jin Kim ),( Yunmi Kim ),( Jae Yoon Park ),( Sung Joon Shin ),( Seung Hyeok Han ),( Dong Ki Kim ),( Chun Soo Lim ),( Yon Su Kim ) 대한신장학회 2019 Kidney Research and Clinical Practice Vol.38 No.1

In 2016 and 2017, there were earthquakes greater than 5.0 in magnitude on the Korean Peninsula, which has previously been considered an earthquake-free zone. Patients with chronic kidney disease are particularly vulnerable to earthquakes, as the term “renal disaster” suggests. In the event of a major earthquake, patients on hemodialysis face the risk of losing maintenance dialysis due to infrastructure disruption. In this review, we share the experience of an earthquake in Pohang that posed a serious risk to patients on hemodialysis. We review the disaster response system in Japan and propose a disaster preparedness plan with respect to hemodialysis. Korean nephrologists and staff in dialysis facilities should be trained in emergency response to mitigate risk from natural disasters. Dialysis staff should be familiar with the action plan for natural disaster events that disrupt hemodialysis, such as outages and water treatment system failures caused by earthquakes. Patients on hemodialysis also need to be educated about disaster preparedness. In the event of a disaster situation that results in dialysis failure, patients need to know what to do. At the local and national government level, long-term preparations should be made to handle renal disaster and patient safety logistics. Moreover, Korean nephrologists should also be prepared to manage cardiovascular disease and diabetes in disaster situations. Further evaluation and management of social and national disaster preparedness of hemodialysis units to earthquakes in Korea are needed.

Fragility based performance evaluation of mid rise reinforced concrete frames in near field and far field earthquakes

Mokhtar Ansari,Amir Safiey,Mehdi Abbasi 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.76 No.6

Available records of recent earthquakes show that near-field earthquakes have different characteristics than far-field earthquakes. In general, most of these unique characteristics of near-fault records can be attributed to their forward directivity. This phenomenon causes the records of ground motion normal to the fault to entail pulses with long periods in the velocity time history. The energy of the earthquake is almost accumulated in these pulses causing large displacements and, accordingly, severe damages in the building. Damage to structures caused by past earthquakes raises the need to assess the chance of future earthquake damage. There are a variety of methods to evaluate building seismic vulnerabilities with different computational cost and accuracy. In the meantime, fragility curves, which defines the possibility of structural damage as a function of ground motion characteristics and design parameters, are more common. These curves express the percentage of probability that the structural response will exceed the allowable performance limit at different seismic intensities. This study aims to obtain the fragility curve for low- and mid-rise structures of reinforced concrete moment frames by incremental dynamic analysis (IDA). These frames were exposed to an ensemble of 18 ground motions (nine records near-faults and nine records far-faults). Finally, after the analysis, their fragility curves are obtained using the limit states provided by HAZUS-MH 2.1. The result shows the near-fault earthquakes can drastically influence the fragility curves of the 6-story building while it has a minimal impact on those of the 3-story building.