• Geophysics and Geophysical Exploration
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• v.13 no.3
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• pp.219-226
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• 2010

Current earthquake alert notification for immediate post-earthquake procedures for the critical facilities is exclusively dependent on the ground-motion intensity measures observed at the seismic station located within the site. This practice is prune to false notification due to a noise and problems of missing and poor quality records of the seismic station. The credibility of the earthquake alert notification can be enhanced by utilizing the multiple transformed records of the nearby seismic stations at other sites interconnected to the same earthquake monitoring system by a network. The time-domain transformation of the site-response between the seismic stations is implemented by convoluting the nearby records with a pair of forward and inverse FIR filters designed for the site response relative to a seismic basement. The transformed records from the nearby seismic stations can be used to estimate the ground-motion intensity measures missing at the site or to evaluate the data quality along with other various possible applications in the area of geoscience and earthquake engineering.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.6
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• pp.1291-1298
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• 2023

Surveillance reconnaissance sensor network is used for surveillance in wartime and area of operation. In this paper, we propose a target localization method using the detection signal strength of seismic sensors. Relay equipment calculates the target location using coordinate information and detection signal strength of the seismic sensors. Target localization error deviation due to environmental factors was minimized by subtracting the dynamic offset when calculating the target location. Field test shows improvement of target localization through reduction of errors. The average error was decreased to 3.62m. Up to 62% improved result was obtained compared to weighted centroid localization method.

• Geophysics and Geophysical Exploration
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• v.13 no.3
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• pp.198-202
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• 2010

In and around the Korean Peninsula, 18 intraplate earthquake focal mechanisms since 1936 were analyzed to understand the characteristic of focal mechanism and regional stress orientation and tectonics. These earthquakes are largest ones from the last century and may represent the characteristics of earthquake in this region. Focal mechanism of these earthquakes show predominant strike-slip faulting with small amount of thrust components. The average P-axis is almost horizontal ENE-WSW direction. This mechanism pattern and the direction of maximum stress axis is very similar with northeastern part of China and southwestern part of Japan. However they are quite different with the eastern part of East Sea. This indicate that not only the subducting Pacific Plate from east but also the indenting Indian Plate controls focal mechanism in the far east of the Eurasian Plate.

• Journal of the Earthquake Engineering Society of Korea
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• v.5 no.4
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• pp.51-66
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• 2001

There occurred a moderate size earthquake of Magnitude 5 in Whagae-Myun, Hadong-GUn, Kyongsangnam-Do on July 4, 1936. It caused severe damage to the buildings and other structures in Sang-Gye-Sa, a Buddhist Temple. The top component of a five-story stone pagoda was tipped over and fell down to the ground during the earthquake. In order to have accurate and quantitative estimate of the peak acceleration level of that earthquake, a full-scale model was constructed through rigorous verification process. The complete model was mounted on a shaking table and subjected to the dynamic tests. Two kinds of tests were performed: exploratory test and fragility test. The exploratory test was done with low acceleration level. In the fragility test, the behavior of the model was carefully monitored while increasing the acceleration level. The construction details of the model are provided and test procedures are reported. Finally important test results are presented and their implications are discussed.

• Economic and Environmental Geology
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• v.39 no.4 s.179
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• pp.369-384
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• 2006

Korean Peninsula, located on the southeastern part of Eurasian plate, belongs to the intraplate region. The characteristics of intraplate earthquake show the low and rare seismicity and the sparse and irregular distribution of epicenters comparing to interplate earthquake. To evaluate the exact seismic activity in intraplate region, long-term seismic data including historical earthquake data should be archived. Fortunately the long-term historical earthquake records about 2,000 years are available in Korea Peninsula. By the analysis of this historical and instrumental earthquake data, seismic activity was very high in 16-18 centuries and is more active at the Yellow sea area than East sea area. Comparing to the high seismic activity of the north-eastern China in 16-18 centuries, it is inferred that seismic activity in two regions shows close relationship. Also general trend of epicenter distribution shows the SE-NW direction. In Korea Peninsula, the first seismic station was installed at Incheon in 1905 and 5 additional seismic stations were installed till 1943. There was no seismic station from 1945 to 1962, but a World Wide Standardized Seismograph was installed at Seoul in 1963. In 1990, Korean Meteorological Adminstration(KMA) had established centralized modem seismic network in real-time, consisted of 12 stations. After that time, many institutes tried to expand their own seismic networks in Korea Peninsula. Now KMA operates 35 velocity-type seismic stations and 75 accelerometers and Korea Institute of Geoscience and Mineral Resources operates 32 and 16 stations, respectively. Korea Institute of Nuclear Safety and Korea Electric Power Research Institute operate 4 and 13 stations, consisted of velocity-type and accelerometer. In and around the Korean Peninsula, 27 intraplate earthquake mechanisms since 1936 were analyzed to understand the regional stress orientation and tectonics. These earthquakes are largest ones in this century and may represent the characteristics of earthquake in this region. Focal mechanism of these earthquakes show predominant strike-slip faulting with small amount of thrust components. The average P-axis is almost horizontal ENE-WSW. In north-eastern China, strike-slip faulting is dominant and nearly horizontal average P-axis in ENE-WSW is very similar with the Korean Peninsula. On the other hand, in the eastern part of East Sea, thrust faulting is dominant and average P-axis is horizontal with ESE-WNW. This indicate that not only the subducting Pacific Plate in east but also the indenting Indian Plate controls earthquake mechanism in the far east of the Eurasian Plate. Crustal velocity model is very important to determine the hypocenters of the local earthquakes. But the crust model in and around Korean Peninsula is not clear till now, because the sufficient seismic data could not accumulated. To solve this problem, reflection and refraction seismic survey and seismic wave analysis method were simultaneously applied to two long cross-section traversing the southern Korean Peninsula since 2002. This survey should be continuously conducted.