Geophysics and Geophysical Exploration (지구물리와물리탐사)

Korean Society of Earth and Exploration Geophysicists (한국지구물리·물리탐사학회)
권호 표지
DOI QR코드

DOI QR Code

Microseismic Monitoring Using Seismic Mini-Array

소규모 배열식 지진관측소를 이용한 미소지진 관측

  • Sheen, Dong-Hoon (Faculty of Earth Systems and Environmental Sciences, Chonnam National University) ;
  • Cho, Chang Soo (Earthquake research center, Korea Institute of Geoscience and Mineral Resources) ;
  • Lee, Hee Il (Earthquake research center, Korea Institute of Geoscience and Mineral Resources)
  • Received : 2013.01.24
  • Accepted : 2013.01.30
  • Published : 2013.02.28
Download PDF
⟨ Previous Next ⟩

Abstract

It was introduced a seismic mini-array that could monitor microseismicity efficiently and analyzed seismic data obtained from the mini-array that was operated from December 19, 2012 to January 9, 2013. The mini-array consisted of a six channel data logger, a central 3 components seismometer, and a tripartite array of vertical sensors centered around the 3 components seismometer as an equilateral triangle with about 100 m aperture. All seismometers that had the same instrument response were connected a 6 channel data logger, which was set to record seismograms at a sampling rate of 200 sps. During the three weeks of campaign, a total of 16 microearthquakes were detected. Using time differences of P wave arrivals from the vertical components, S-P time from 3 components seismometers, and back azimuth from the seismic array analysis, it was possible to locate the hypocenter of the microearthquake even with one seismic miniarray. The epicenters of two nearest microearthquakes were a quarry site located 1.3 km from the mini-array. The records of quarry blasting confirmed the our analysis.

효과적으로 미소지진을 관측하고 분석할 수 있는 소규모 배열식 지진 관측소와 분석 방법을 소개하였으며, 관측능력을 확인하기 위해 2012년 12월 19일부터 2013년 1월 9일까지 시험 관측을 수행하였다. 중앙에 6 채널 지진 기록계 1 대와 3 성분 지진계 1 대를 설치하고 수직성분 지진계 3 대를 중앙으로부터 약 100 m 정도 떨어진 지점에 삼각형 형태로 각 꼭짓점에 설치하여 소규모 배열식 지진관측소를 구성하였다. 모든 지진계는 동일한 계기 응답 함수를 가지며 하나의 6 채널 지진 기록계에 연결되어 200 sps 의 간격으로 관측 자료를 저장하였다. 3 주의 시험 관측 기간 동안 총 16 개의 미소 지진을 관측하였다. 수직성분 지진계에서 관측한 P파의 도달시간 차이, 3 성분 지진계에서 관측한 P파와 S파의 도달시간 차이, P파와 S파 지진 파형의 배열식 분석으로 얻은 후방 방위각들을 이용해 지진의 진원을 결정하기 때문에 하나의 소규모 배열식 관측소만으로도 진원 결정이 가능하였다. 가장 가까운 거리에서 발생한 미소 지진 2 개의 진앙은 관측 부지로부터 1.3 km 거리에 있는 채석장으로 분석되었으며, 채석장의 발파 기록과 분석된 결과가 서로 일치함을 확인하였다.

Keywords

References

  1. Chang, S.-J., and Baag, C.-E., 2006, Crustal structure in Southern Korea from joint analysis of regional broadband waveforms and travel times, Bull. Seism. Soc. Am., 96, 856-870. https://doi.org/10.1785/0120040165
  2. De Matteis, R., Matrullo, E., Rivera, L., Stabile, T. A., Pasquale, G., and Zollo, A., 2012. Fault delineation and regional stress direction from the analysis of background microseismicity in Southern Apennines, Italy, Bull. seism. Soc. Am., 102, 1899-1907. https://doi.org/10.1785/0120110225
  3. Goodway, B., 2012, Introduction to this special section: Passive seismic and microseismic-Part 1, The leading edge, 31, 1296-1299. https://doi.org/10.1190/tle31111296.1
  4. Häge, M., and Joswig, M., 2009, Spatiotemporal characterization of interswarm period seismicity in the focal area Nov Kostel (West Bohemia/Vogtland) by a short-term microseismic study, Geophys. J. Int., 179, 1071-1079. https://doi.org/10.1111/j.1365-246X.2009.04320.x
  5. Hauksson, E., Armbruster, J., and Dobbs, S., 1984, Seismicity patterns (1963-1983) as stress indicators in the Shumagin seismic gap, Alaska, Bull. Seism. Soc. Am., 74, 2541-2558.
  6. Joswig, M., 2008, Nanoseismic monitoring fills the gap between microseismic networks and passive seismic, First break, 26, 117-124.
  7. Julian, B. R., and Foulger, G. R., 2009, Monitoring geothermal process with microearthquake mechanisms, 34th workshop on geothermal reservoir engineering, Proceedings, SGP-TR-187.
  8. Phillips, W. S., 2000, Precise microearthquake locations and fluid flow in the geothermal reservoir at Soultz-sous-Forts, France, Bull. Seism. Soc. Am., 90, 212-228. https://doi.org/10.1785/0119990047
  9. Pujol, J., 2004, Earthquake location tutorial: graphical approach and approximate epicentral location techniques, Seism. Res. Let., 75, 63-74. https://doi.org/10.1785/gssrl.75.1.63
  10. Rost, S., and Thomas, C., 2002, Array seismology: methods and applications, Rev. Geophys., 40, 1008, doi:10.1029/2000RG000100.
  11. Serpetsidaki, A., Tselentis G.-A., Martakis, N., and Sokos, E., 2012, Seismicity and seismotectonics study in southwestern Albania using a local dense seismic network, Bull. Seism. Soc. Am., 102, 2090-2097. https://doi.org/10.1785/0120110139
  12. Sheen, D.-H., Shin, J. S., and Kang, T.-S., 2009, Seismic noise level variation in South Korea, Geosciences Journal, 13, 183-190. https://doi.org/10.1007/s12303-009-0018-0
  13. Sparks, R. S. J., Biggs, J., and Neuberg, J. W., 2012, Monitoring volcanoes, Science, 335, 1310-1311. https://doi.org/10.1126/science.1219485
  14. Tosha T., Doi, N., and Koide, K., 2000, Monitoring of a geothermal reservoir utilizing microearthquakes, 25th workshop on geothermal reservoir engineering, Proceedings, SGP-TR-165.
  15. Wust-Bloch, G. H., and Joswig, M., 2006, Pre-collapse identification of sinkholes in unconsolidated media at Dead Sea area by 'Nanoseismic Monitoring' (graphical jackknife-location of weak sources by few, low-SNR records). Geophys. J. Int., 167, 1220-1232. https://doi.org/10.1111/j.1365-246X.2006.03083.x

Cited by

  1. Study on Microseismic Data Acquisition and Survey Design through Field Experiments of Hydraulic Fracturing and Artificial Blasting vol.18, pp.4, 2015, https://doi.org/10.7582/GGE.2015.18.4.197