• Korean Journal of Remote Sensing
• /
• v.21 no.1
• /
• pp.15-29
• /
• 2005

Superconducting Gravimeters (SG) are the most sensitive instruments for measuring temporal gravity variations. The gravimeter is an integrating sensor therefore the gravity variations caused by different sources must be separated for studying a special effect by applying different models and data analysis methods. The present reduction methods for gravity variations induced by atmosphere and hydrosphere including the ocean and the detection and determination of the most surface gravity effects are shown. Some examples demonstrate the combination of ground (SG) and space techniques especially the combination of SG with GRACE satellite derived temporal gravity variations. Resulting from the performance of the SG and the applied data analysis methods some proposals are made for future SG applications.

• Proceedings of the KSRS Conference
• /
• 2004.10a
• /
• pp.42-42
• /
• 2004

• Proceedings of the KSRS Conference
• /
• v.1
• /
• pp.156-156
• /
• 2006

• Korean Journal of Remote Sensing
• /
• v.21 no.1
• /
• pp.3-13
• /
• 2005

National Research Lab Project 'Optimal Data Fusion of Geophysical and Geodetic Measurements for Geological Hazards Monitoring and Prediction' supported by Korea Ministry of Science and Technology is briefly described. The research focused on the geohazard analysis with geophysical and geodetic instruments such as superconducting gravimeter, seismometer, magnetometer, GPS, and Synthetic Aperture Radar. The aim of the NRL research is to verify the causes of geological hazards through optimal fusion of various observational data in three phases: surface data fusion using geodetic measurements; subsurface data fusion using geophysical measurements; and, finally fusion of both geodetic and geophysical data. The NRL hosted a special session 'Geohazard Monitoring with Space and Geophysical Technology' during the International Symposium on Remote Sensing in 2004 to discuss the current topics, challenges and possible directions in the geohazard research. Here, we briefly describe the special session papers and their relationships to the theme of the special session. The fusion of satellite and ground geophysical and geodetic data gives us new insight on the monitoring and prediction of the geological hazard.

• Economic and Environmental Geology
• /
• v.40 no.4
• /
• pp.445-459
• /
• 2007

Superconducting Gravimeter(SG) was installed and has been successfully operated at MunGyung, Kyungsang province in Korea in March 2005. It was registered as the 21st observatory of the Global Geodynamics Project. Since SG can precisely measure the gravity variations below the 1mHz frequency band, it has the outstanding capability to sense and resolve many different periodic gravity components from each other. From the raw data collected between 18 March 2005 and 21 February 2006 diurnal and semi-diurnal tidal band's residual gravity components were analyzed. During this process, the instrumental noises, air pressure, and ground water corrections were carried out. Values of $-3.18nm/s^2/hPa\;and\;17nm/s^2/m$ were used respectively in the air pressure and groundwater corrections. Hartmann-Wenzel and Whar-Dehant Earth tide models were adopted to compute the residual gravity for Q1, O1, P1, K1, M2, N2, S2, K2 tidal bands. For the ocean loading correction, SCW80, FES952, and FES02 models were used and compared. As a result, FES02 ocean loading model has shown the best match for the data processing at MunGyung SG MunGyung SG gravity was compared with GRACE satellite gravity. The correlation coefficient between the two gravity after groundwater correction was 0.628, which is higher than before ground water correction. To evaluate sensitivity at MunGyung SG gravity statition, the gravity data measured during 2005 Indodesian earthquake was compared with STS-2 broad band seismometer data. The result clearly revealed that the SG could recorded the same period of earthquake with seismometer event and a few after-shock events those were detected by seismometer.

• Korean Journal of Remote Sensing
• /
• v.21 no.1
• /
• pp.31-49
• /
• 2005

We first review some history of the Global Geodynamics Project (GGP), particularly in the progress of ground-satellite gravity comparisons. The GGP Satellite Project has involved the measurement of ground-based superconducting gravimeters (SGs) in Europe for several years and we make quantitative comparisons with the latest satellite GRACE data and hydrological models. The primary goal is to recover information about seasonal hydrology cycles, and we find a good correlation at the microgal level between the data and modeling. One interesting feature of the data is low soil moisture resulting from the European heat wave in 2003. An issue with the ground-based stations is the possibility of mass variations in the soil above a station, and particularly for underground stations these have to be modeled precisely. Based on this work with a regional array, we estimate the effectiveness of future SG arrays to measure co-seismic deformation and silent-slip events. Finally we consider gravity surveys in volcanic areas, and predict the accuracy in modeling subsurface density variations over time periods from months to years.