[보고서]지구물리학적 지진 전조 현상 연구

이희순

지구물리학적 지진 전조 현상 연구
Study of earthquake preceding phenomena in geophysics 원문보기

보고서 정보
주관연구기관	(주)아이피그룹
연구책임자	이희순
참여연구자	박용열 , 나현주 , 지은관 , 노승미 , 류희영
보고서유형	1단계보고서
발행국가	대한민국
언어	한국어
발행년월	2012-03
과제시작연도	2011
주관부처	기상청
사업 관리 기관	기상청 Korea Meteorological Administration
등록번호	TRKO201200001094
과제고유번호	1365001174
DB 구축일자	2013-04-18
키워드	지진 전조,지자기장,자기지전류,한반도 지전기 구조earthquake precursory,geomagnetic field,magnetotelluric,geoelectrical structure of the Korean Peninsula

초록 ▼

본 연구는 크게 두 부분으로 나뉜다.
첫째는 한반도의 심부 전기비저항 분포에 관한 연구이다. 지진에 의한 전조현상으로서의 자기장의 왜곡은 매우 국지적인 특성을 나타낸다. 따라서 외국의 지진전조로서의 자기장 왜곡이 한반도에 그대로 적용되지는 않는다. 이러한 메카니즘을 이해하기 위해서는 한반도 심부 전기비저항 분포를 아는 것이 무엇보다도 중요하다고 하겠다. 이러한 전기비저항 분포는 통상적인 천부의 전기비저항 분포를 연구하는 방법인 전기 탐사로는 측정 불가능한 심부영역이다. 따라서 본 연구에서는 MT 탐사를 통해 한반도의 심부 전기 비저항 분포를 측정하였다. 또한 한반도의 지리적 특성상 MT 탐사자료에는 해양효과가 많이 들어간다. 이를 위해 해양효과를 효율적으로 제거하는 연구를 진행하였다.
두 번째는 청양에 설치한 자기장 상시관측소의 자료 분석이다. 본 연구는 기존 연구를 참조하여 개량된 분극 분석방법을 개발하고, 이를 이용하여 청양관측소의 지자기 삼성분 자료를 분석하였다. 분석 주파수는 지진발생에 가장 민감하다고 알려진 0.01 Hz 대역이며, 분극값을 일단위로 계산하였다. 분석결과를 Kp 인덱스 및 동일기간 발생한 지진이벤트와 비교하였다.

Abstract ▼

This research have tested and checked about the possibilities of detection of the Earthquakes in Korean Peninsula. This research can be aparted in two parts.
First, we have studied on the deep electric structure of Korean peninsula. As a precusor, the distortion of electromagnetic wave has severe localities. So, the phenomena of electromagnetic distortion of other countries can not be adopted on the those of Korean Peninsula. Thus, it is very important to verify the distribution of resistivities in Korean Peninsula. In this study, MT(Magnetotellurics ) exploration method have been applied to delineate the deep electric structure in Korean peninsula. Though, MT has a merit for the deep structure but has a defect of distortion of low frequency data from sea effect which makes a distorted earth model. I have showed that this sea effect has been removed effectively form original MT data.
From the result of this study, Gyeongsan basin and Gyeonggi province has Conrad discontinuities about depths at 12 km and 17 km , respectively.
Second, it is analysed the data of Cheongyang magnetic observatory maintained by KMA. This study develops the modified polarization analysis method based on the previous studies, and analyzes three-component geomagnetic fields obtained at Cheongyang geomagnetic observatory using the developed method. A daily polarization value was calculated with a focus on the 0.01 Hz band, which is known to be the most sensitive to seismogenic ULF radiation. The geonagnetic data have been analyzed, and compare the polarization values with the Kp index and the earthquake occurred in the analysis period. The results show that there is little correlation between the temporal variations of polarization values and Kp index, but remarkable increases in polarization values are identified which are associated with two earthquakes. Comparison the polarization values obtained at Cheongyang and Kanoya observatory indicates that the increases of polarization values at Cheongyang might be due to not global geomagnetic induction but the locally occurred earthquakes. Furthermore, these features are clearly shown in normalized polarization values, which take account in the statistical characteristics of each geomagnetic field. On the basis of these results, polarization analysis can be used as promising tool for monitoring the earthquake-precursory phenomenon.

목차 Contents

표지 ... 1
제출문 ... 2
보고서 요약서 ... 3
요약문 ... 4
SUMMARY ... 6
목차 ... 8
제 1 장 연구개발과제의 개요 ... 9
1절 연구개발의 필요성 ... 9
제 2 장 국내외 기술개발 현황 ... 11
1절 기술개발의 필요성 ... 11
2절 미국 등 선진국의 연구 진행상황 ... 11
3절 국내수준 ... 12
제 3 장 연구개발수행 내용 및 결과 ... 13
1절 지진전조 탐지를 위한 한반도 광역 지전기 구조 연구 ... 13
2절 지자기장 자료에 나타나는 지진전조 관련 이벤트 분석 ... 50
제 4 장 목표달성도 및 관련분야에의 기여도 ... 76
제 5 장 연구개발결과의 활용계획 ... 79
제 6 장 연구개발과정에서 수집한 해외과학기술정보 ... 80
제 7 장 연구개발결과의 보안등급 ... 81
제 8 장 국가과학기술종합정보 시스템에 등록한 연구시설·장비현황 ... 81
제 9 장 참고문헌 ... 82
[첨부 1] 연구개발결과 활용계획서 ... 86
[붙임1] 연구개발결과 활용계획서 ... 87
[붙임2] 기술 요약서 ... 91
[첨부 2] 연구개발결과의 보안 등급 ... 96
[첨부 3] 국가연구시설·장비 정보 및 등록 현황 ... 97
[별첨 2] 자체평가의견서 ... 100
[별첨 3] 최종보고서 체크리스트 ... 104
[별첨 5] 보고서 배포결과 ... 105
[별첨 6] 연구개발결과 공개제한 요청사유서 ... 106
[별첨 7] 연구개발결과 활용계획서 ... 107

표/그림 (35)

표 Regional geological map in and around the Hwasan caldera area (modified after Yoo et al., 2005). The MT profile in this study has been designed to go across the Hwasan caldera with the direction of EW.
표 Map showing the elevation of observed MT sites, regional and local geological boundaries.
표 Observed apparent resistivity and phase curves at selected sites (9 sites).
표 Bahr's phase-sensitive skew for all sites. The solid line in lower panel indicates the threshold value above which the 2-D assumption for subsurface is violated (0.3 for Bahr's skew).
표 The results of Groom-Bailey decomposition technique when the strike direction is constrained to be 0o (NS direction).
표 Apparent resistivity and phase curve of the site 9, 10, 11, 12 and 13. Although these sites are laid on the similar geological environment, their apparent resistivity curves show a scattered feature keeping their phase curves consistent in both modes.
표 The inverted 2-D resistivity model in and around the Hwasan caldera area, which was derived form the NLCG inversion algorithm. (a) Observed and calculated apparent resistivity and phase, (b) 2-D inverted resistivity model and rms error by site, (c) surface geological units along the MT profile.
표 2-D gravity modeling based on the MT inversion results (after Um, 2007). The observed gravity anomalies are explained well by the 2-D density model that is derived from the inverted resistivity structure.
표 Simplified geological boundaries including the location of observed MT sites. The sites KMT102, KMT103, KMT104 and KMT106 are located in the Kyongsang Basin, but KMT136, KMT136 and KMT140 in the Kyonggi Massif, respectively.
표 Three-dimensional model including surrounding seas of the Korean Peninsula for correcting the sea effect. Bathymetry data were complied from ETOPO5 data-set (http://www.ngdc.noaa.gov /mgg/global) and simplified for the convenience of numerical modeling..
표 1-D inverted resistivity model obtained by Occam inversion at each iteration stage for the site KMT102. (b) Observed (circle) and sea effect corrected (triangle) apparent resistivity and phase curves at the 2nd iteration, respectively. © RMS misfit between Zo and Z at each iteration stage. The model at the initial iteration is the model without sea effect correction.
표 1-D inverted resistivity model obtained by Occam inversion at each iteration stage for the site KMT136. (b) Observed (circle) and sea effect corrected (triangle) apparent resistivity and phase curves at the 2nd iteration, respectively. © RMS misfit between Zo and Z at each iteration stage. The model at the initial iteration is the model without sea effect correction.
표 1-D inverted resistivity model at each iteration stage for the sites KMT102, KMT103, KMT104 and KMT106, which are located in the eastern Kyongsang Basin.
표 1-D resistivity models obtained by the inversion with 4 layers for the sites KMT102, KMT103, KMT104 and KMT106 before correcting the sea effect.
표 1-D resistivity models obtained by the inversion with 4 layers for the sites KMT102, KMT103, KMT104 and KMT106 after correcting the sea effect.
표 A bathymetry map around Jeju Island. A total of 102 MT sites (cross hairs) are distributed along five survey lines (JSL: Jeju Southern Line, JNL: Jeju Northern Line, JEL: Jeju Eastern Line, JWL: Jeju Western Line, JCL: Jeju Central Line).
표 3-D Jeju model including the surrounding seas over 1-D resistivity model (Table 1). The seawater depth is simplified into 5 steps of 10, 20, 40, 70 and 100 m. The horizontal grid spacing shown in the model is 2 km.
표 Pseudo-sections of the observed (uncorrected) data and the sea-effect-corrected data for the JSL: (a) apparent resistivityand (b) impedance phase of the XY and YX modes.
표 Pseudo-sections of the observed (uncorrected) data and the sea-effect-corrected data for the JNL: (a) apparent resistivity and (b) impedance phase of the XY and YX modes.
표 Pseudo-sections of the observed (uncorrected) data and the sea-effect-corrected data for the JEL: (a) apparent resistivity and (b) impedance phase of the XY and YX modes.
표 Pseudo-sections of the observed (uncorrected) data and the sea-effect-corrected data for the JWL: (a) apparent resistivity and (b) impedance phase of the XY and YX modes.
표 Pseudo-sections of the observed (uncorrected) data and the sea-effect-corrected data for the JCL: (a) apparent resistivity and (b) impedance phase of the XY and YX modes.
표 2-D resistivity models of the XY and YX modes obtained by the NLCG inversion algorithm (a) with and (b) without sea-effect correction for the JNL.
표 The map showing the earthquakes occurred within 200 km from the Cheongyang observatory (site CHY) during March to August 2009. The solid lines indicate major tectonic boundaries of the southern Korean Peninsula. The Kanoya observatory (site KNY) is a fixed permanent observatoryoperated by Japan Meterological Agency.
표 Temporal variations of geomagnetic transfer functions A
표 Temporal polarization results (Hz/Hx and Hz/Hy) for the period of (a) 109 s and (b) 123 s at the Cheongyang observatory, before applying standardization. The earthquakes occurred within 200 km from the Cheongyang observatory are displayed. The lowest panel shows the daily averages of Kp index. The vertical arrows indicate anomalous peaks associated with earthquake occurrences.
표 Temporal polarization results (Hz/Hx and Hz/Hy) for the period of (a) 109 s and (b) 123 s at the Cheongyang observatory, after applying standardization. The earthquakes occurred within 200 km from the Cheongyang observatory are displayed. The lowest panel shows the daily averages of Kp index. The vertical arrows indicate anomalous peaks associated with earthquake occurrences.
표 Temporal polarization results (Hz/Hx and Hz/Hy) for the period of (a) 109 s and (b) 123 s at the Kanoya observatory, after applying standardization. The earthquakes occurred within 200 km from the Kanoya observatory are displayed. The lowest panel shows the daily averages of Kp index.
표 The map showing the earthquakes occurred within 100 km from the Cheongyang observatory during March to December 2009(note that the earthquake No. 1 exceeds a distance of 100 km from the observatory but has the largest magnitude in the analysis period). The solid lines indicate major tectonic boundaries of the southern Korean Peninsula. The Kanoya observatory is a fixed permanent observatory operated by Japan Meterological Agency. The number in the map indicate the occurred earthquake event number listed in Table 1.
표 Conventional (top curve) and robust (bottom curve) power spectra for the time variations of the north magnetic field at Cheongyang Observatory, Korea. The conventional spectrum is the arithmetic average of 167 independent pieces of data, whereas the bottom line is the robust average of the same data.
표 Temporal variations of spectral power densities of 3-component geomagnetic fields for 0.01 Hz at the Cheongyang observatory.
표 Temporal variations of polarization values (Hz/Hx and Hz/Hy) for 0.01 Hz at the Cheongyang observatory, before applying standardization. The earthquakes occurred within 100 km from the Cheongyang observatory are displayed.
표 Temporal variations of polarization values (Hz/Hx and Hz/Hy) for 0.01 Hz at the Kanoya observatory, Japan, before applying standardization. The earthquakes occurred within 100 km from the Cheongyang observatory are displayed.
표 Temporal variations of polarization values (Hz/Hx and Hz/Hy) for 0.01 Hz at the Cheongyang observatory, after applying standardization. The earthquakes occurred within 100 km from the Cheongyang observatory are displayed. The arrows indicate anomalous increases associated with earthquake occurrences.
표 Temporal variations of polarization values (Hz/Hx and Hz/Hy) for 0.01 Hz at the Kanoya observatory, Japan, after applying standardization. The earthquakes occurred within 100 km from the Cheongyang observatory are displayed.

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연합인증

지구물리학적 지진 전조 현상 연구
Study of earthquake preceding phenomena in geophysics 원문보기