• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.3
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• pp.311-318
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• 2011

On March 11, 2011, an 9.0-magnitude earthquake occurred near the northeastem coast Japanese. It was the largest earthquake that hit Japan since the beginning of modern seismometry. The earthquake occurred 179km east of the Sendai, Miyagi Prefecture, leaving about 27,000 of people confirmed dead, injured or missing due to the earthquake and tsunami. In this study, crustal Deformation in Mizusawa, Tsukuba and Usuda station were calculated based on GPS data in IGS station of Japan. The observation data were processed by precise point positioning and relative-positioning method using on-line GPS data processing services and a high precision scientific GPS/GLONASS data processing software. The coseismic displacements in IGS stations before and after the earthquake were analyzed using kinematic precise point positioning method, and the crustal deformation of the areas before and after the earthquake were precisely calculated using the relative-positioning method. The results of the study calculated precise coordination that the RMSE is maximum ${\pm}0.003m$, respectively and showed that Mizusawa station moved 2.6m southeast by the earthquake.

• Explosives and Blasting
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• v.27 no.2
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• pp.48-55
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• 2009

In the process of identifying the earth's crust structures to accurately locate the seismic epicenter, man-made earthquakes need to be generated. Such a large-scale ground vibration can be generated by a deep borehole blasting, but it can also accompany some environmental impacts on the surroundings. In this respect, a borehole test blasting was carried out to determine the maximum charge weight that could be used without affecting the various structures around the blast site. Total 400kg of gelatine-type dynamites was used in the test blast. As a result, a prediction equation for ground vibrations was derived from the measured data. With the allowable level of 3.0 mm/s for residential structures, the maximum charge weight was determined to be 677kg if military structures near the site were considered. But if the military structures were not considered, it was found that up to 2100kg of explosives could be used without affecting old houses in the nearby village.

• Magazine of the Korean Society of Agricultural Engineers
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• v.53 no.3
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• pp.35-41
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• 2011

최근 증가하고 있는 자연재해 중 지진재해가 전체 재해에서 차지하는 비중은 상대적으로 적지만, 빈도와 강도가 증가하고 있으며, 대응하기 위한 예측 체계가 거의 없다는 것이 어려운 점이다. 일본의 후쿠오카 지진 이후 내진설계 기준이 강화되고 있으나 실제 지진발생시 최대가속도의 크기와 전파속도에 대한 이론적인 연구는 있었지만 국가적 차원의 자료 구축은 거의 없었다. 2005년 이후 소방방재청에서 지진방재종합개선기획단이 구성된 이후, 각 기관에 산재된 GIS 자료를 수집하여, 지진상황에 맞는 자료로 가공하고 프로그램으로 구현하게 되었다. anyguide라는 지리정보 시스템과 Java 어플리케이션으로 구성된 프로그램을 통하여 과거의 지진자료와 측정지점에 대한 정보를 구축하였으며, 실제 지진 발생시에 지자체에서 대응할 수 있는 경보시스템을 동시에 구축하였다. 2007년 2월에 발생한 평창 주변의 지진발생시 시스템이 작동하여 실제 shake map과 hazard map이 작성되었으며, 실제 인명과 건물 파괴 비율을 검증할 수 있었다. 이처럼 지진에 신속히 대응하기 위해서는 최단 시간내에 피해의 규모와 범위를 파악하여야 하고, 이에 따라서 적절한 대응 조치를 취해야 하는 점에서 지진재해대응 시스템은 그 활용 범위가 계속 확대될 것으로 예상된다.

• Journal of the Korean earth science society
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• v.41 no.3
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• pp.238-247
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• 2020

This study simulated strong ground motion waveforms in the southern Korean Peninsula, based on the physical earthquake modeling of the Southern California Earthquake Center (SCEC) BroadBand Platform (BBP). Characteristics of intensity attenuation were investigated for M 6.0-7.0 events, incorporating the site effects. The SCEC BBP is software generates broadband (0-10 Hz) ground-motion waveforms for earthquake scenarios. Among five available modeling methods in the v16.5 platform, we used the Song Model. Approximately 50 earthquake scenarios each were simulated for M 6.0, 6.5, and 7.0 events. Representative metrics such as peak ground acceleration (PGA) and peak ground velocity (PGV) were obtained from the synthetic waveforms that were simulated before and after the consideration of site effects (V_S30). They were then empirically converted to distribution of instrumental intensity. The intensity that considers the site effects is amplified at low rather than high V_S30 zones.

• Computational Structural Engineering
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• v.17 no.2
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• pp.31-41
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• 2004

몇 일 전 필자는 대전에 위치한 한 연구소에 근무하고 계신 분으로부터 지진취약도 분석에 관한 문의 전화를 받았다. 그분의 대학 후배가 지진취약도에 대한 연구를 하고 싶다는 내용이었다. 최근 필자는 그분 외에도 다른 분들과 함께 지진취약도 분석 및 이를 확장한 바람에 의한, 혹은 홍수에 의한 구조물의 확률적 안전성 분석에 관한 논의를 하곤 하였다. 현재까지 국내에서는 구조물의 취약도 분석에 대한 연구가 그다지 활발하지 않으나, 이에 대한 관심은 지속적으로 증가할 것으로 보여진다. 지진취약도를 한마디로 요약하면, "임의의 크기를 갖는 지진이 발생하였을 때, 구조물에 어느 규모 이상의 손상이 발생할 확률"을 의미하는 것으로, 구조물의 확률적 지진안전성으로 부를 수 있다. 예를 들어, "최대지반가속도가 0.1g인 지진이 발생하였을 때, 해당 구조물에 보수를 요하는 수준 이상의 손상이 발생할 확률이 30%이다"와 같은 정보를 지진취약도 곡선으로부터 읽을 수 있다. (중략)

• Proceedings of the Korean Society of Disaster Information Conference
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• 2016.11a
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• pp.240-241
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• 2016

본 논문에서는 지난 9월 12일에 한반도 관측 이래 최대 규모 5.8 지진이 발생한 경주 피해현황 대장(엑셀)을 지자체로부터 제공받아 피해현황에 대해 공간분석을 실시하였다. 현황정보를 기반으로 지진피해 주소 데이터를 기반으로 지오코딩을 수행하였으며 약 5,906건(95.6%)에 대한 속성정보를 공간정보화 하였다. 지질도 및 단층정보로 구축한 공간DB를 중첩 분석하여, 시각화된 지진피해 현황 결과를 제시하였다. 마지막으로 지진피해지역의 특징 및 현황 분석이 일차적으로 이루어져야 하며, 향후 지진피해 데이터 및 공간분석을 기반으로 지진 발생시 피해가 예상되는 지역에 대해 예측하는 모델링 및 시스템 고도화를 추진해야 할 것이다.

• Journal of Korea Society of Industrial Information Systems
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• v.26 no.4
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• pp.33-46
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• 2021

In Korea 2016, the largest earthquake occurred in Gyeongju since the beginning of monitoring earthquakes. Consecutively the second-largest earthquake occurred in Pohang. At that time, immediately after the earthquake, citizens were not notified adequate information for evacuation. In consequence the response process was very confusing and citizens were not able to properly evacuate to shelter. For resolving these problems, it is needed of a service to inform quickly information which citizens want to know immediately after the earthquake. So, we have developed the customized information service model, the earthquake safety service which help citizens to escape safely using an earthquake shaking alert device. In this paper, we will introduce this model and present the future direction of R&D and strategic plans for technology dissemination and improvement of practicality through user demand survey.

• Tunnel and Underground Space
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• v.32 no.3
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• pp.203-218
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• 2022

A hydro-mechanical study was performed to analyze the relationship between the magnitude of injection-induced seismicity and shut-in. In hydraulic analysis, the suspension of fluid injection makes the pore pressure gradient smaller while the pore pressure at the pressure front can reach the critical value for several hours after shut-in, which leads to the additional slip with wider area than during injection. The hydro-mechanical numerical analysis was performed to model the simplified fault system, and simulated the largest magnitude earthquake during shut-in stage. The effect of the abrupt suspension of fluid injection on the large magnitude earthquake was investigated in comparison with the continuous injection. In addition to the pore pressure distribution, it was found that the geometry of multiple faults and the stress redistribution are also important in evaluating the magnitude of the induced seismicity.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.3
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• pp.95-103
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• 2008

Knowledge of expected losses in terms of physical, economic, and social damages due to a potential earthquake will be helpful in the effort to mitigate seismic hazards. In this study, losses due to a magnitude 6.7 scenario earthquake in the Gyeongju area have been estimated using the deterministic method in HAZUS. The attenuation relation proposed by Sadigh et al.(1997) for site classes B, C, and D, which are assumed to represent the characteristics of the strong-motion attenuation in the Korean Peninsula, has been applied. Losses due to the hypothetical earthquake have been also calculated using other attenuation relationships to examine their roles in the loss estimation. The findings indicate differences among the estimates based on various attenuation relationships. Estimated losses of the Gyeongju area by a scenario earthquake using HAZUS should be seriously considered in the planning of disaster response and hazard mitigation.

• Journal of the Korean Geotechnical Society
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• v.35 no.11
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• pp.121-129
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• 2019

An Earthquake Early Warning (EEW) system is a technology that alerts people to an incoming earthquake by using P waves that are detected before the arrival of more severe seismic waves. P-wave analysis is therefore an important factor in the production of rapid seismic information as it can be used to quickly estimate the earthquake magnitude and epicenter through the amplitude and predominant period of the observed P-wave. However, when a large-magnitude teleseismic earthquake is observed in a local seismic network, the significantly attenuated P wave phases may be mischaracterized as belonging to a small-magnitude local earthquake in the initial analysis stage. Such a misanalysis may be sent to the public as a false alert, reducing the credibility of the EEW system and potentially causing economic losses for infrastructure and industrial facilities. Therefore, it is necessary to develop methods that reduce misanalysis. In this study, the possibility of seismic misclassifying teleseimic earthquakes as local events was reviewed using the Filter Bank method, which uses the attenuation characteristics of P waves to classify local and outside Korean peninsula (regional and teleseismic) events with filtered waveform depending on frequency and epicenter distance. The data used in our analysis were analyzed for maximum P_v values using 463 events with local magnitudes (2 < M_L ≦ 3), 44 (3 < M_L ≦ 4), 4 (4 < M_L ≦ 5), 3 (M_L > 5), and 89 outside Korean peninsula earthquakes recorded by the KMA seismic network. The results show that local and telesesimic earthquakes can be classified more accurately when combination of filtering bands of No. 3 (6-12 Hz) and No. 6 (0.75-1.5 Hz) is applied.