• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.10a
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• pp.49-56
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• 2000

Instrumental observation of earth quakes in KIGAM was first attempted in the earty 1980`s by using 6 portable seismographs in the vicinity of Yang-San Faults. Now twenty-four permanent stations, which are equipped with short-period or broad-band seismometer, are included in seismic research network in KIGAM, including KSRS array station in Wonju which is consisted of 26 bore-hole stations. The seismic network of KIGAM is also linked to that of KEPRI(Korea Electric Power Research Institute)which is consisted of eight stations installed within and around the nuclear power plants. Owing to real-time data acquisition by telemetry, it became feasible to automatically locate hypocenters of the local events within fifteen minutes by computer data processing system, named KEMS(Korea Earthquake Monitoring System). Results of the hypocenter determination, together with observational data, are compiled and stored in the data base system. And they are published via web site whose URL is http://quake.kigam.re.kr KIGAM is also running t재 permanent geomagnetic stations installed in Daejun and Kyungju. The observed geomagnetic data are transmitted to Earthquake Research Centre in KIGAM by seismic network and compiled for the purpose of earthquake prediction research and other basic geophysical research.

• Journal of the Korean earth science society
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• v.42 no.2
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• pp.195-200
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• 2021

Orientation corrections for the total of 268 accelerograph stations of the Korea Meteorological Administration (KMA) were estimated using ambient noise cross-correlation. As this method uses ambient noise data instead of teleseismic waveforms from earthquakes under certain conditions, reliable orientation corrections can be obtained using only two-month long continuous seismic data from dense seismic networks in the Korean peninsula.Three-component continuous data recorded at the 268 accelerograph stations from January to February 2020 were used to estimate orientation corrections. The results are comparable to the previous results obtained from teleseismic waveforms; the overall standard deviations of the orientation corrections are less than 5°. Therefore, orientation corrections for the accelerograph station network can be tracked periodically by the ambient-noise method and the result can be used in various studies using the horizontal-component of acceleration data.

• Geophysics and Geophysical Exploration
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• v.18 no.2
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• pp.85-90
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• 2015

Orientation corrections for Korean seismic stations were calculated by using ambient noise cross-correlation. This method uses Rayleigh waves extracted from ambient noise cross-correlation instead of teleseismic waveforms from earthquakes, which have been generally used for previous studies. The theoretical background of the method is that the phase of radial-vertical cross-correlation function should be the same as that of $90^{\circ}$ phase-shifted vertical-vertical cross-correlation function. The results calculated from stacked cross-correlograms from Jan. 2007 to Sep. 2008 are comparable to the previous results obtained from teleseismic waveforms. In addition, overall the standard deviations of orientation corrections are less than $5^{\circ}$. The temporal variation in orientation corrections calculated for every 30 days shows no significant change and also standard deviations of them are mostly less than $5^{\circ}$. This means that the orientations of stations used in this study have been kept constant during the period. The sensitivity test for stacking period of the ambient noise cross-correlation method shows that continuous ambient noise record of at least about 30 days is required for estimating reliable orientation corrections.