• Explosives and Blasting
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• v.18 no.3
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• pp.83-88
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• 2000

국내 지진관측소로부터 분석된 지진기록에는 자연지진 이외의 상당수의 인공발파를 포함하는 것으로 해석된다. 자연지진에 대한 지진특성연구, 지질학적 지진의 진원지연구 등을 위 해서는 지진목록에서 인공발파를 식별할 필요가 있다. 한국자원연구소는 인공발파 식별을 위한 연구의 일환으로 지진-공중음파 관측망을 운영 중에 있다. 지진-공중음파 자료분석으로 구분된 인공발파 기록의 대부분이 발파를 실시하는 산업현장과 일치하고 있음이 확인되었다. 발파장의 위치, 발파시간, 규모 및 발파방법 등의 정보는 공중음파를 이용한 인공발파 식별에 관한 정량적 연구와 자연지진에 관한 연구 등에 기본적인 정보(Ground Truth Database)를 제공하리라 판단되므로 국내에서 실시되는 인공발파에 대한 정보가 요구된다.

• The Journal of Engineering Geology
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• v.10 no.2
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• pp.98-112
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• 2000

Discrimination between natural earthquakes and man-made explosions is very essential but critical matter in Seismology. In the CTBT Monitoring business, this is very crucial issue and sometimes could occur the international conflict. In this study, we analyzed seismic and infrasound data from Chulwon Seismo-Acoustic Array and would like to introduce routine data processing procedures at the Korea Institute of Geology, Mining and Materials(KIGAM) to discriminate the earthquakes and artificial explosions. We found analyzing acoustic data together with seismic data is very effective way to identify and discriminate man made explosion from natural earthquake. Recent earthquakes in and around the Korean Peninsula are concentrated in a narrow zone with N60-70$^{\circ}$W in southern Korea, and Pyungan and Hwanghae Province in northern Korea. The mechanism of 14 larger earthquakes in and around the Korean Peninsula since 1936 show predominant strike-slip faulting together with minor thrust component. This indicates horizontal compression is dominant in and around the Korean Peninsula.

• Proceedings of the KSEEG Conference
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• 2001.04a
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• pp.354-355
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• 2001

• Economic and Environmental Geology
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• v.36 no.3
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• pp.201-212
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• 2003

Recently, the ability of earthquake detection in the Kyungsang Basin of southeastern Korean Peninsula is greatly improved since seismic stations including seismic network of KIGAM(Korea Institute of Geoscience and Mineral Resources) have been significantly increased. However, a large number of signals from explosions are recorded because of frequent medium to large chemical explosions. The discrimination between natural earthquakes and explosions in the Basin has become an important issue. High frequency local records from 43 earthquakes and 43 explosions with comparable magnitude are selected to establish a reliable discrimination technique in the Basin. Several discrimination techniques in spectral domain using spectral amplitude ratios among Pg, Sg, and Lg waves are widely examined with tile selected data. Among them the Pg/Lg spectral ratio method is appeared to be a good discrimination technique to improve the discrimination power. Multivariate discriminant analysis is also applied to the Pg/Lg spectral ratios. The discrimination power of the Pg/Lg ratios for distance corrected three component record compared to uncorrected vertical component one shows distinct improvement. In the frequency band 4 to 14 Hz, Pg/Lg spectral ratio for distance corrected three component record provides discrimination power with a total misclassification probability of only 0.89%.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2002.03a
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• pp.59-63
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• 2002

Artificial blasts, defined as seismo-acoustic events, were discriminated from natural earthquakes in the Korean Peninsula by analyzing seismo-acoustic data. 219 seismo-acoustic events corresponding to 9 percent of total seismic events in 2001 were analyzed and classified as artificial surface blasts. Most seismo-acoustic events were concentrated in several areas. This distribution pattern was similar to the previous result in 1999-2000. Most of seismo-acoustic events especially concentrated at 7 small areas in North and South Korea. The number of seismo-acoustic events occurred in North and South Korea was 79 and 140 events, respectively. The local magnitude of seismic events from North Korea was relatively larger than from South. And some infrasound occurred from North Korea had a characteristic of sequential arrivals of signals, which reflected the different propagation in the atmosphere.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.03a
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• pp.38-44
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• 2003

Artificial blasts, defined as seismo-acoustic events, were discriminated from natural earthquakes in the Korean Peninsula by the seismo-acoustic analysis. Total 197 seismo-acoustic events corresponding to 9 percent of seismic events in 2002 were analyzed and classified as artificial surface blasts. Events distribution pattern of the seismo-acoustic events in 2002 was similar to the previous result in 1999-2001, except for two regions. Newly determined seismo-acoustic events were added to the previous artificial blast database. To extend infrasound detection capability, new small-scale infrasound array(TJIAR) was installed in KIGAM. Preliminary analysis for the small array was conducted to discriminate artificial blasts in the southwestern part of the Korean Peninsula. The small array discriminated S seismo-acoustic events during short period analysis. And two infrasound arrays(TJIAR and CHNAR) were used to determine approximate sound source location by cross bearing method.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2005.03a
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• pp.68-73
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• 2005

In succession of the previous works, seismo-acoustic analysis was conducted to collect ground truth events and to discriminate surface explosions from natural earthquakes in the Korean Peninsula for 2004. In this period, total 510 seismo-acoustic events corresponding to 10.8 percent of total seismic events occurred in and near the Korean Peninsula were analyzed and discriminated as artificial surface explosions. Events distribution of the seismo-acoustic events in 2004 is similar to the previous results of 1999-2003. And newly determined seismo-acoustic events were added to the surface explosions database. To extend infrasound detection capability, Korea Institute of Geoscience and Mineral Resources (KIGAM) and Southern Methodist University (SMU) installed new seismo-acoustic array (BRDAR) in Baekryoung Island last November, 2004. The array configuration and design is nearly same to previous seismo-acoustic arrays CHNAR, KSGAR, a triangular 1 km aperture. BRDAR consists of 5 short period vertical seismometers (GS-13) in seismic vaults and 13 microbarometers (Chaparral Model 2). Preliminary analysis using data collected from BRDAR shows an extension of infrasound detection capability to western part of the Korean Peninsula. Also, multiple observations of infrasound at BRDAR and other arrays gave an opportunity to localize sound source regions.

• Geophysics and Geophysical Exploration
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• v.13 no.3
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• pp.286-294
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• 2010

Korea Institute of Geoscience and Mineral Resources (KIGAM) has installed and operated seven seismoacoustic (infrasound) arrays as well as seismic stations in Korea. The seismo-acoustic array, which consists of co-located seismometers and micro-barometers, can observe both seismic and infrasonic signals from distant explosive phenomena. The infrasound is defined as low frequency (<20 Hz) acoustic waves in atmosphere. In particular, it can be detectable at long distance due to its low energy attenuation during propagation in atmosphere. KIGAM adopted the infrasound technology to discriminate surface explosions from earthquakes only because the surface explosion generally generates infrasound following seismic signal. In addition to surface explosions, these arrays have detected diverse geophysically natural and artificial phenomena, such as infrasound signal from the North Korean nuclear test. This review introduced the state-of-the-art studies and examples of infrasonic signals in and around the Korean Peninsula. In conclusion, infrasound technology would be clearly accepted itself as a new Earth monitoring technology by expanding its detectable regime to lithosphere-Earth surface-atmosphere. In future, an advanced technology, which allows to analyze seismic and infrasonic wave fields together, will enlarge the understanding of geophysical phenomena and be used as a robust analysis method for remote explosive phenomena in the broad infrasound regime.