• Journal of the Korean Society of Industry Convergence
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• v.21 no.6
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• pp.317-327
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• 2018

The perception of earthquake in Korea has changed due to the earthquake that occurred in Gyeongju and Pohang, and the earthquake has become an important factor in infrastructure management. Damage to infrastructures in the event of an earthquake is extensive. In particular, damage to infrastructures that perform public function used to spread to the whole area. From the point of view of earthquake disaster prevention, it is very important for the public to define what infrastructures are important management targets and to prepare a countermeasure. In this study, we propose a method to evaluate the importance of infrastructure to effectively manage infrastructures for earthquakes. For this purpose, important factors for the railway bridges, power generation and electric power facilities, and apartment complexes are suggested. AHP analysis is conducted to suggest priorities. In addition, the evaluation criteria for infrastructure importance are presented.

• Earthquakes and Structures
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• v.22 no.3
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• pp.305-318
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• 2022

This paper presents a comparative study of the damage potentials for the 2016 Gyeongju and 2017 Pohang earthquakes in Korea. Plausible technical explanations are provided for the more severe damage observed in the 2017 Pohang earthquake in spite of its relatively weaker magnitude and intensity measures based on the response analysis of elastic and inelastic single-degree-of-freedom systems for the recorded ground motions. In addition, a detailed case study was conducted for a fatally damaged piloti building with an eccentric shear wall core based on nonlinear dynamic analysis using the input ground motions modified for the building site.

• Journal of the Korean Institute of Landscape Architecture
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• v.45 no.4
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• pp.62-70
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• 2017

Following the September $12^{th}$, 2016 earthquake in Gyeongju-city, the observation can be made that South Korea is not a non-earthquake country. Because of its particular characteristics, urban green spaces are good sites for protection during an earthquake but studies regarding the suitability of park green spaces as a form of earthquake shelter are few, making it difficult to highlight the function of park green spaces as emergency shelters. The purpose of this study is to identify indicators for suitability impact factors of comprehensive parks as emergency earthquake shelter zones. Using the Delphi method, three rounds of survey were implemented. According to the analysis results of Average value, CVR, Consultation and Convergence, ten candidate indicators were removed in the candidate group. Twenty-seven suitability impact factors of comprehensive parks were retained, including 8 indicators in the field of safety, 6 indicators in the field of accessibility, and 13 indicators in the field of service effectiveness.

• Korean Journal of Remote Sensing
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• v.34 no.6_4
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• pp.1531-1544
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• 2018

We detected the coseismic ionospheric disturbance generated by the earthquakes of magnitude 5.0 and greater in Korean Peninsula. We considered the seismic events such as Gyeongju earthquake in September 2016 with magnitude 5.8, the Pohang earthquake in November 2017 with magnitude 5.4, and the underground nuclear explosion from North Korea in September 2017 with magnitude 5.7. Although all GPS stations were not detected, the ionospheric disturbance induced by these earthquakes occurred approximately 10-30 minutes and 40-60 minutes after the events. We inferred that the time difference within each variation is due to the different focal depth and the geometry of epicenter, satellite, and GPS station. In the case of the Gyeongju earthquake, the earthquake had relatively deeper depth than the other earthquakes. However, the seismic magnitude was bigger and it occurred at nighttime when the ionospheric activity was stable. So we could observe such anomalous variations. It is considered that the ionospheric disturbance caused by the difference in velocity of the upward propagating waves generated by earthquake appears more than once. Our results indicate that the detection of ionospheric disturbances varies depending on the geometry of the GPS station, satellite, and epicenter or the detection method and that the apparent growth of amplitude in the time series varies depending on the focal depth or the site-satellite-epicenter geometry.

• The Journal of Engineering Geology
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• v.29 no.1
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• pp.1-12
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• 2019

Earthquake can change underground stress condition around the hypocenter and affect the fracture systems of the rocks. In Korea, the M5.8 Gyeongju earthquake on September 12, 2016 and M5.4 Pohang earthquake on November 15, 2017 occurred inside the Yangsan fault zone and possibly affected the fracture systems in the Yangsan fault zone and nearby rock masses. In this study, the characteristics of the fracture system (fracture orientation, number of the fractures, fracture spacing and aperture, dip angle, fracture density along depth, and relative rock strength) of the rocks in the low/intermediate level radioactive waste repository site located in the coastal area of the East Sea are analyzed by the impact of the Gyeongju and Pohang earthquakes using acoustic televiewer data taken from the boreholes at the radioactive waste repository site in 2005 and 2018. As a result of acoustic televiewer logging analysis, the fracture numbers, fracture aperture, and fracture density along depth overall increased in 2018 comparing to those in 2005. This increase tendency may be due to changes in the fracture system due to the impact of the earthquakes, or due to weathering of the wall of the boreholes for a long period longer than 10 years after the installation of the boreholes in 2005. In the borehole KB-14, on the whole, the orientation of the fractures and the average fracture spacing are slightly different between 2005 and 2018, while dip angle and relative rock strength in 2005 and 2018 are similar each other.

• Journal of the Earthquake Engineering Society of Korea
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• v.27 no.3
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• pp.139-145
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• 2023

It is essential to determine a proper earthquake time history as a seismic load in a seismic design for a critical structure. In the code, a seismic load should satisfy a design response spectrum and include the characteristic of a target fault. The characteristic of a fault can be represented by a definition of a type of possible earthquake time history shape that occurred in a target fault. In this paper, the pseudo-basis function is proposed to be used to construct a specific type of earthquake, including the characteristic of a target fault. The pseudo-basis function is derived from analyzing the earthquake time history of specific fault harmonic wavelet transform. To show the feasibility of this method, the proposed method was applied to the faults causing the Gyeong-Ju ML5.8 and Pohang ML5.3 earthquakes.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.8 no.3
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• pp.467-475
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• 2018

Recently earthquakes have been increasing worldwide, and the largest earthquake of 5.8 on the Richter scale occurred on September 12, 2016 in the Gyeongju area. After the earthquake, more than 200 aftershocks have occurred from January 2017 to December 2017. The largest earthquake in 2017 was a 4.3-magnitude earthquake near Pohang on November 15. In this study, we tried to analyze the coordinate change due to the earthquake using the data of the CORS(Continuously Operating Reference Station) in Korea. In order to analyze the change of coordinates due to the earthquake in Pohang area on November 15, 2017, data processing was performed by kinematic method. And from January 2017 to December 2017, observation data of 9 stations in Korea were analyzed by relative positioning method and the change of coordinates due to earthquake was analyzed. As a result of the study, it was possible to estimate the instantaneous coordinate change due to the earthquake through the kinematic positioning, and it was suggested that there is no change in the coordinates of the domestic CORS by the relative positioning results. After the 2017 Gyeongju earthquake, aftershocks continue to occur, and it is necessary to monitor the area continuously.

• The Korean Journal of Applied Statistics
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• v.30 no.5
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• pp.759-774
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• 2017

Earthquake concerns have grown after a remarkable earthquake incident on September 12th, 2016 in Gyeongju, Korea. Earthquake forecasting is gaining in importance in order to guarantee infrastructure safety and develop protection policies. In this paper, we adopt a power-law distribution model to fit past earthquake occurrences in Korea with various historical and modern seismological records. We estimated power-law distribution parameters using empirical distributions and calculated the future probabilities for large earthquake events based on our model. We provide the probability that a future event has a larger magnitude than given levels, and the probability that a future event over certain levels will occur in a given period of time. This model contributes to the assessment of latent seismological risk in Korea by estimating future earthquake probabilities.

• Journal of the Earthquake Engineering Society of Korea
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• v.23 no.4
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• pp.221-229
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• 2019

Several water tanks installed in the building were damaged during the Gyeongju earthquake (2016) and the Pohang earthquake (2017). Since a water tank for fire protection is very important component, seismic safety should be ensured. In this study, an interaction between a water tank and a building was studied by the dynamic analysis of the RC building with the water tank. In case the water tank was installed on the roof of the RC building, it was confirmed that it did not significantly affect the response of the building. Based on the result, dynamic response characteristics of the water tank in the building were studied using two SDOF models represented dynamic behavior of the water tanks under earthquake. An earthquake time-history analysis was carried out with variables of aspect ratio of the tank, story of the building, and installed location in the building using three kinds of earthquakes.

• Journal of the Earthquake Engineering Society of Korea
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• v.20 no.7_spc
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• pp.561-567
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• 2016

After the Gyeong-ju 9.12 earthquake, we found the necessity of seismic design of nonstructural element is important to reduce damages in view of properties and economic losses. This study focused on the investigation of damages including both properties and human beings. It was found that most of the damages are leaking of water pipe line, rupture of glasses, spalling of roof finishing, cracks of building, and falling from roof. It was also found that the seismic design force of nonstructural elements is taking account into the natural periods, amplification factors, response modification factors to forsee inelastic behaviors. From this studies, it is recommended that more studies are necessary on the seismic design force of nonstructural element.