도시와 재해 도시와 지진

이기화 대한지방행정공제회 1986 도시문제 Vol.21 No.3

N/A

옥천 지향사내 주요단층대의 구역화 및 지구물리학적 연구

이기화,이전희 대한지질학회 1993 대한지질학회 학술대회 Vol.1993 No.

서울 수도권 일원의 지진위험 분석 1

이기화,이태국 한국지진공학회 1997 한국지진공학회논문집 Vol.1 No.4

MM진도(Modified Mercalli Intensity) V이상의 한반도 지진자료에 의거하여 서울 수도권일원 (위도 37.0^{circ}~37.8^{circ} N, 경도 126.5^{circ}~127.5^{circ} E) 의 확률론적인 지진위험도가 점지진원방법에 의해 추정되었다. 전지진자료를 이용하여 추정된 지진위험도는 비교적 완전하다고 여겨지는 조선시대이후의 지진자료를 이용하여 추정된 지진위험도보다 더 낮다고 추정되었다. 수평지반가속도 0.1g 이상의 파괴적인 지진은 90% 초과확률로서 전지진자료와 조선시대이후의 지진자료가 이용되었을 때 각각 500년과 200년 기간에 발생한다. The probabilistic seismic risk in Seoul Metropolitan Area (atitude도 37.0^{circ}~37.8^{circ} N, longitude 126.5^{circ}~127.5^{circ} E) based on all Korean earthquake data of MM Intensity equal to or greater than V is evaluated by point source method. The seismic risk estimated from all data turned out to be lower than that from the data since the Choseon Dynasty during which seismic data appear to be rather complete. The damaging earthquake of peak horizontal ground acceleration greater than 0.1g turns out to occur with 90% probability of being exceeded in 200 years and 500 years when the data since Choseon Dynasty and all data are used, respectively.

특집 - 내진설계의 문제 : 한반도의 지진위험도

이기화 대한건축학회 1988 建築 Vol.32 No.2

많은 국민들이 한반도가 지진의 재해로부터 면제된 지역이라고 생각해 왔었으나 1978년 10월 7일 홍성에서 발생한 수정 머켈리진도(Modified Mercalli Intensity) 의 지진은 국민들의 부정확한 고정관념에 큰 충격을 주었다. 당시 이 지진은 홍성읍내의 홍주성, 조양문등 주요 문화재와 중학교 교사등 여러 건조물을 파손하여 약 4억원의 재산피해를 가져왔다. 20세기에 들어와서 홍성지진외에 1936년 7월 4일지리산 쌍계사근처에 역시 수정머켈리진도 의 지진이 발생하여 사원의 건물을 크게 파괴하였다.

2016년 9월 경주지진 소고(小考)

이기화,Lee, Kiehwa 한국지구물리물리탐사학회 2017 지구물리와 물리탐사 Vol.20 No.3

2016년 9월 12일 규모 5.8의 본진을 포함한 일련의 지진들이 경주에서 발생했다. 본진은 1905년 한반도에서 지진관측을 시작한 이래 반도 남부에서 발생한 최대의 지진으로서 양산단층이 명백한 활성단층임을 입증하였다. 콘래드 불연속면이 없는 단층의 한반도 지각 모델에 의한 경주지진들의 전진, 본진, 여진들의 평균깊이는 12.9 km로 콘래드 불연속면이 있는 2층 구조의 IASP91 모델에 의한 평균깊이보다 2.8 km 낮다. 경주지역에서 발생한 역사지진 및 계기지진들의 진앙분포는 주 단층인 양산단층과 부속 단층을 포함하는 양산단층계가 광범위한 파쇄대임을 시사한다. 규모 5.8의 경주지진에 수반한 지진들의 진앙분포는 양산단층계의 몇 단층들이 응력에너지의 방출에 관여하였음을 지시한다. 경주지진들의 주요 지진들이 지표가 아닌 10 km 이하에서 발생한 것은 양산단층계의 심부 활성단층들의 분포를 연구할 필요성을 제기한다. 경주지역의 지진자료에 근거하여 추정한 이 일대의 최대지진의 규모는 7.3이다. 한반도의 가장 완전한 1978년 이후의 지진자료를 이용하여 추정한 경주지역의 규모 5.0, 6.0, 7.0을 초과하는 지진들의 재현간격은 각기 80년, 670년, 그리고 5,900년이다. 2016년 9월 경주지진들은 본질적으로 판내부지진활동의 범주에 속하며 2011년 3월 11일 일본해구에서 발생한 판경계지진횔동인 동일본대지진과는 무관하다. A sequence of earthquakes with the main shock $M_L$ 5.8 occurred on September 12 2016 in the Gyeongju area. The main shock was the largest earthquakes in the southern part of the Korean peninsula since the instrumental seismic observation began in the peninsula in 1905 and clearly demonstrated that the Yangsan fault is seismically active. The mean focal depth of the foreshock, main shock, and aftershock of the Gyeongju earthquakes estimated by the crustal model of single layer of the Korean peninsula without the Conrad discontinuity turns out to be 12.9 km, which is 2.8 km lower than that estimated based on the IASP91 reference model with the Conrad discontinuity. The distribution of the historical and instrumental earthquakes in the Gyeongju area indicates that the Yangsan fault system comprising the main Yangsan fault and its subsidiary faults is a large fracture zone. The epicenters of the Gyeongju earthquakes show that a few faults of the Yangsan fault system are involved in the release of the strain energy accumulated in the area. That the major earthquakes of Gyeongju earthquakes occurred not on the surface but below 10 km depth suggests the necessity of the study of the distribution of deep active faults of the Yangsan fault system. The magnitude of maximum earthquake of the Gyeongju area estimated based on the earthquake data of the area turns out to be 7.3. The recurrence intervals of the earthquakes over magnitudes 5.0, 6.0 and 7.0 based on the earthquake data since 1978, which is the most complete data in the peninsula, are estimated as 80, 670, and 5,900 years, respectively. The September 2016 Gyeongju earthquakes are basically intraplate earthquakes not related to the Great East Japan earthquake of March 11 2011 which is interplate earthquake.

Raw and processed electroencephalography in modern anesthesia practice: a brief primer on select clinical applications

이기화,Egan Talmage D,Johnson Ken B 대한마취통증의학회 2021 Korean Journal of Anesthesiology Vol.74 No.6

The evidence supporting the intraoperative use of processed electroencephalography (pEEG) monitoring to guide anesthetic delivery is growing rapidly. This article reviews the key features of electroencephalography (EEG) waveforms and their clinical implications in select patient populations and anesthetic techniques. The first patient topic reviewed is the vulnerable brain. This term has emerged as a description of patients who may exhibit increased sensitivity to anesthetics and/or may develop adverse neurocognitive effects following anesthesia. pEEG monitoring of patients who are known to have or are suspected of having vulnerable brains, with focused attention on the suppression ratio, alpha band power, and pEEG indices, may prove useful. Second, pEEG monitoring along with vigilant attention to anesthetic delivery may minimize the risk of intraoperative awareness when administering a total intravenous anesthesia in combination with a neuromuscular blockade. Third, we suggest that processed EEG monitoring may play a role in anesthetic and resuscitative management when adverse changes in blood pressure occur. Fourth, pEEG monitoring can be used to better identify anesthesia requirements and guide anesthetic titration in patients with known or suspected substance use.

Canada 서해(西海)의 Seismicity

이기화,Lee, Kiehwa 대한자원환경지질학회 1978 자원환경지질 Vol.11 No.1

This paper examines the seismicity of the offshore area of western Canada in the light of findings from a detailed study of an earthquake swarm which occurred in the area during November-December in 1971. The distribution of epicenters and focal mechanism solutions of a few main events suggest that the seismicity of the area may largely be interpreted in terms of plate interactions among the Pacific, Juan de Fuca, Explorer and North American plates. Differences between the patterns of seismicity along the transform fracture zones and at their junctions with the ridges were also observed.

제주도 지하수의 Ghyben-Herzberg 관계 소고

이기화 대한지질학회 1991 대한지질학회 학술대회 Vol.1991 No.

유한차분법을 이용한 3차원 전기비저항구조 모델링

이기화,윤종렬 대한지질학회 1997 대한지질학회 학술대회 Vol.1997 No.

난지도에 인접한 한강변에서의 쌍극자-쌍극자 전기탐사

이기화,권병두,오석훈,김차섭,Lee, Kiehwa,Kwon, Byung-Doo,Oh, Seok-Hoon,Kim, Cha-Seop 대한자원환경지질학회 1996 자원환경지질 Vol.29 No.3

The dipole-dipol electrical resistivity survey was conducted to investigate the probable contamination of the Han river by leachate from the near-by Nanjido Landfill. The survey line of 3 km was set along the unpaved road toward the Han river. For the convenience of the field work, the survey line was divided into four segments. The complete two-dimensional resistivity section was constructed by connecting the inversion result of each segment. Gravity survey was also carried out along the profile parallel to the resistivity line. Near surface resistivity generally appeared to be of very low value in most part of the survey area and the boundary between the alluvium layer and underlying basement rocks is well discriminated on the resistivity section. These results agree well with those of the preceding Schlumberger depth sounding made at adjacent area by Lee and fun (1995). The variation of thickness of the alluvium layer delineated by gravity anomaly profile also correlates well with the result of the resistivity survey on the qualitative basis. The problem of contamination by leachate from the Nanjido Landfill, where various waste materials have been dumped without any proper treatment facilities, has been remains unsolved yet. Therefore, we present the most probable passages of leachate flow based on the survey results and have briefly discussed about measure for contamination control. Considering the thickness of alluvium and the possible existence of fractured zone, the middle point between 1st and 2nd landfill and the midst of 1st landfill are the most hazardous regions to make leachates flow into the Han river. Since large amounts of leachates are observed from the test wells located on the lines extending from the border between the 1st and 2nd landfill and the middle of the lst landfill, contamination protection barriers are strongly recommended near these regions.