• Title/Summary/Keyword: distance to epicenter

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Seismic effects of epicenter distance of earthquake on 3D damage performance of CG dams

  • Karalar, Memduh;Cavusli, Murat
    • Earthquakes and Structures
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    • v.18 no.2
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    • pp.201-213
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    • 2020
  • Seismic damages that occurred by the effects of epicenter distance of the earthquake are one of the most important problems for the earthquake engineering. In this study, it is aimed to examine the nonlinear seismic behaviors of concrete gravity (CG) dams considering various epicenter distances. For this purpose, Boyabat CG dam that is one of the biggest concrete gravity dams in Turkey is selected as a numerical application. FLAC3D software based on finite difference method is used for modelling and analyzing of the dam. Drucker-Prager nonlinear material model is used for the concrete body and Mohr-Coulomb nonlinear material model is taken into account for the foundation. Special interface elements are used between dam body and foundation to represent interaction condition. Free-field and quiet non-reflecting boundary conditions are utilized for the main surfaces of 3D model. Total 5 various epicenter distances of 1989 Loma Prieta earthquake are considered in 3D earthquake analyses and these distances are 5 km, 11 km, 24 km, 85 km and 93 km, respectively. According to 3D seismic results, x-y-z displacements, principal stresses and shear strain failures of the dam are evaluated in detail. It is clearly seen from this study that the nonlinear seismic behaviors of the CG dams change depending to epicenter distance of the earthquake. Thus, it is clearly recommended in this study that when a CG dam is modelled or analyzed, distance of the earthquake fault to the dam should be strongly examined in detail. Otherwise, earthquake damages can be occurred in the concrete dam body by the effects of seismic loads.

Estimation of epicenter using an empirical relationship between epicentral distance and traveltime of the first arrival (초동 전파시간과 진앙거리의 경험적인 관계를 이용한 진앙 추정)

  • Sheen, Dong-Hoon;Baag, Chang-Eob;Hwang, Eui-Hong;Jeon, Young-Soo
    • 한국지구물리탐사학회:학술대회논문집
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    • 2007.06a
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    • pp.64-68
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    • 2007
  • The classic graphical method to determine the epicenter uses differences between the arrival times of P and S waves at each station. In this research, a robust approach is proposed, which provides a fast and intuitive estimation of earthquake epicenters. This method uses an empirical relationship between epicentral distance and traveltime of the first arrival P phase of local or regional earthquake. The relationship enables us to estimate epicentral distances and draw epicentral circles from each station with P-traveltimes counted from a probable origin time. As the assigned time is getting close to the origin time of the earthquake, epicentral circles begin to intersect each other at a possible location of the epicenter. Then the possibility of the epicenter can be expressed by a function of the time and the space. We choose the location which gives the minimum standard deviation of the origin time as an estimated epicenter. In this research, 918 P arrival times from 84 events occurring from 2005 to 2006 listed in the KMA earthquake catalog are used to determine the empirical P-traveltime function of epicentral distances.

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Engineering implications of the RC building damages after 2011 Van Earthquakes

  • Ozmen, Hayri Baytan;Inel, Mehmet;Cayci, Bayram Tanik
    • Earthquakes and Structures
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    • v.5 no.3
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    • pp.297-319
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    • 2013
  • Two destructive earthquakes occurred on October 23 and November 9, 2011 in Van province of Turkey. The damage in residential units shows significant deviation from the expectation of decreasing damage with increasing distance to epicenter. The most damaged settlement Ercis has the same distance to the epicenter with Muradiye, where no damage occurred while relatively less damage observed in Van having half distance. These three cities seem to have resembling soil conditions. If the damages are evaluated: joint failures and insufficient lap splice lengths are observed to be the main causes of the total collapses in RC buildings. Additionally, low concrete strength, reinforcement detailing mistakes, soft story, heavy overhang, pounding and short columns are among other damage reasons. Examples of damages due to non-structural elements are also given. Remarkable points about seismic damages are: collapsed buildings with shear-walls, heavily damaged buildings despite adequate concrete strength due to detailing mistakes, undamaged two-story adobe buildings close to totally collapsed RC ones and undamaged structural system in buildings with heavily damaged non-structural elements. On the contrary of the common belief that buildings with shear-walls are immune to total collapse among civil engineers, collapse of Gedikbulak primary school is a noteworthy example.

A Study on the Integration of Objects and Environment in the Surface with Changing Materiality of Prada Aoyama Epicenter (프라다 아오야마 에피센터 건축에서 나타나는 환경과 사물과 통합되는 다층적 물질성의 표면에 관한 연구)

  • Kim, Heebum;Kang, Jae-Hyuk;Choi, Weonah
    • Journal of the Architectural Institute of Korea Planning & Design
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    • v.34 no.2
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    • pp.33-40
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    • 2018
  • The purpose of this study was to analyze integration of the surface of Prada Aoyama Epicenter by Herzog & de Meuron. To understand various aspects of surfaces & constituents related, each elevations are analyzed minutely by distance both inside and outside. The results of this study were as follows; the individual surface of Prada Aoyama Epicenter sets a multi-layered relationship with the actual environment. Their architectural surface still has a significance in presenting a way of creating a building along with everyday surroundings.

Prediction of Peak Ground Acceleration Generated from the 2017 Pohang Earthquake (2017년 포항지진으로 인하여 발생된 최대지반가속도 (PGA)예측)

  • Jee, Hyun Woo;Han, Sang Whan
    • Journal of the Earthquake Engineering Society of Korea
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    • v.22 no.3
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    • pp.211-217
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    • 2018
  • The Pohang earthquake with a magnitude of 5.4 occurred on November 15, 2018. The epicenter of this earthquake located in south-east region of the Korean peninsula. Since instrumental recording for earthquake ground motions started in Korea, this earthquake caused the largest economic and life losses among past earthquakes. Korea is located in low-to moderate seismic region, so that strong motion records are very limited. Therefore, ground motions recorded during the Pohang earthquake could have valuable geological and seismological information, which are important inputs for seismic design. In this study, ground motions associated by the 2018 Pohang earthquake are generated using the point source model considering domestic geological parameters (magnitude, hypocentral distance, distance-frequency dependent decay parameter, stress drop) and site amplification calculated from ground motion data at each stations. A contour map for peak ground acceleration is constructed for ground motions generated by the Pohang earthquake using the proposed model.

Ionospheric F2-layer Perturbations Observed After the M8.8 Chile Earthquake on February 27, 2010, at Long Distance from the Epicenter

  • Hegai, Valery V.;Kim, Vitaly P.;Legen'ka, Anna D.
    • Journal of Astronomy and Space Sciences
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    • v.34 no.1
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    • pp.1-5
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    • 2017
  • The F2-layer critical frequency (foF2) data from several ionosondes are employed to study the long-distance effect of the M8.8 Chile Earthquake of February 27, 2010, on the F2 layer. Significant perturbations of the peak F2-layer electron density have been observed following the earthquake at two South African stations, Hermanus and Madimbo, which are located at great circle distances of ~8,000 and ~10,000 km from the earthquake epicenter, respectively. Simplified estimates demonstrate that the observed ionospheric perturbations can be caused by a long-period acoustic gravity wave produced in the F-region by the earthquake.

Characteristic Investigation of the Bedrock Earthquake Records for the Structural Time-History Seismic Analyses (구조물의 시간이력 지진해석을 위한 암반지진기록의 특성분석)

  • Kim, Yong-Seok
    • Journal of the Earthquake Engineering Society of Korea
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    • v.12 no.1
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    • pp.89-95
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    • 2008
  • Until recently lots of time-history seismic analyses were performed with the earthquake motions recorded at the soft soil surface without taking into account the effects of the soft soil amplification. However, it is important to utilize the bedrock seismic motions for the rational seismic analyses of a structure considering the site soil conditions. In this study, 26 bedrock earthquake records were selected from publicly available 1557 seismic records provided by the Pacific Earthquake Engineering Research Center (PEER) for the study, and the characteristics of them were investigated. Study results showed that it is not reasonable to estimate earthquake acceleration intensity from the magnitude of an earthquake without considering the site soil conditions and it is also hard to draw any general relationships between earthquake acceleration intensity, earthquake magnitude and epicenter distance with bedrock earthquake records in the PEER database. However, 26 bedrock earthquake records selected in this study can be utilized for the time-history seismic analyses of a structure-soil system as bedrock earthquake ones, and it is also confirmed that it is necessary to take into account acceleration intensity, magnitude, epicenter distance and site conditions simultaneously for the proper use of those selected earthquake records.

Earthquake-related Data Selection using Event Packets (이벤트 패킷을 이용한 지진관련 데이터의 추출)

  • Lim, In-Seub;Jung, Soon-Key
    • Journal of the Korea Society of Computer and Information
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    • v.13 no.6
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    • pp.59-68
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    • 2008
  • In this paper, we propose a method for selecting meaningful event packets from which can receive before anything else from seismograph according to allotted priority and estimate epicenter using selected packets. Event packets which received from each station will be evaluated with their onset time, signal period and SNR by statistical method and will be selected packets related with real earthquake's P-wave. And estimated epicenters using by 'Application of epicenter estimation using first P arrivals'. With local earthquakes occurred in 2007 were announced by KMA, collected event packets on earthquake happened date and selected p-wave related packets and estimated epicenter. After result of experiment, if an earthquake occurred within seismic networks, can estimate epicenter with small misfits just after event packets arrived from above 4 stations. Considering average distance of each station, in case of using all stations' data include other organization, can estimate and alert rapidly. It show this method is useful when construct a local earthquake early warning system later.

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A Numerical Study on the Effective Dimension in Slot-drilling Method (슬롯드릴링공법의 유효제원에 관한 수치해석적 연구)

  • Yoon, Ji-Sun;Lee, Jee-Hoon;Son, Sung-Hoon
    • Explosives and Blasting
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    • v.28 no.2
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    • pp.50-58
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    • 2010
  • This study explores the slot-drilling method that has not yet enough been studied in Korea and intends to provide a theoretical framework for putting the method into practice in a construction site. The possible reduction of ground vibration by implementing slot-drilling methods is addressed. Two main subjects dealt with include the variation of vibration velocity that is based on the distance between the slot-drilling and the epicenter of blasting and the analysis of appropriate effective dimension of slot-drilling width and height to control blasting vibration. This study shows that effect of vibration reduction decreases when distance of the slot-drilling and the epicenter of blasting is getting larger and also reveals that there is a correlation between the slot size and the vibration velocity at any point.

Analysis of Seismic Response Characteristics for Wolsong Nuclear Power Plant Structures (월성원전 구조물의 지진응답 특성 분석)

  • 허택영
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 1997.10a
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    • pp.90-97
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    • 1997
  • The purpose of this study is to evaluate the seismic response characteristics of Wolsong nuclear power plant (NPP) structures for the Kyeongju earthquake(ML=4.3) occurred on June 26, 1997. The seismograms are obtained from five accelerographs of nuclear power plant at Wolsong, Kyeongbuk. The distance from the epicenter is about 25km. The peak acceleration (PA) due to the earthquake is 0.0235g, which is far lower value than that of design basis earthquake(DBE). The PA at the containment wall is about twice as large as that at free field. Also, the higher the accelerograph is located in, the larger the PA is measured to be From the response spectrum analysis, the dominant frequency of the response is close to 4 Hz, which is similar to the free field is poor because of contamination by high frequency waves as a result of reflection and diffraction between ground and NPP structure. We are of opinion that the accelerograph at the free field should be moved approximately twice the building dimension away from the containment structure.

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