Gravity Survey along the Mizuho Traverse Routes, East Antarctica: SEAL Seismic Exploration in 1999-2000

Shigeru Toda, Hiroki Miyamachi, Hiroshi Murakami, Tomoki Tsutsui, Masaki Kanao

Department of Earth and Environmental Sciences, Faculty of Science, Kagoshima University, Kagoshima, Japan.
Department of Earth Sciences, Faculty of Education, Aichi University of Education, Kariya, Japan.
Faculty of Engineering and Resource Science, Akita University, Akita, Japan.
National Institute of Polar Research, Tokyo, Japan.
Technical Center for Seismological Observations Ltd., Tsukuba, Japan.

DOI: 10.4236/ijg.2013.410136                

Abstract

A gravity survey was conducted along the Mizuho traverse routes in austral summer of 1999-2000 by the 41^st Japanese Antarctic Research Expedition (JARE-41). The main purpose of the survey was to obtain detail gravity anomaly along the traverse routes, where deep seismic exploration was simultaneously conducted in order to obtain a fine crustal structure of the Mizuho Plateau. By using SCINTREX (CG-3M) gravity meter, the survey was carried out at 160 sites with about 1 km interval in a distance of 190 km from S16 to Z20 on the traverse routes. Free-air and Bouguer anomalies were calculated using precise locations by GPS measurements, by taking into account an effect of the thick icesheet. The furrowed negative Free-air anomalies are identified around H192, where middle points of the whole traverse routes. Two bedrock elevation models derived both by seismic refraction analyses and radio-echo sounding might correspond to the bottom and the top of a mixture layer composed from ice-moraine rocks over the bedrock surface. Thickness of the crust estimated by Bouguer anomalies is 0.5 - 1 km larger toward inland at the terminal point of Z20 along the profile.

Keywords

Gravity Survey; Mizuho Traverse Routes; Bedrock Elevation; Bouguer Gravity Anomaly; Crustal Structure

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	K. Shiraishi, D. J. Ellis, Y. Hiroi, C. M. Fanning, Y. Motoyoshi and Y. Nakai, “Cambrian Orogenic Belt in East Antarctica and Sri Lanka; Implications for Gondwana Assembly,” The Journal of Geology, Vol. 102, No. 1, 1994, pp. 47-65. http://dx.doi.org/10.1086/629647
[2]	M. Kanao, M. Ishikawa, M. Yamashita, K. Kaminuma and L. D. Brown, “Structure and Evolution of the East Antarctic Lithosphere: Tectonic Implications for the Development and Dispersal of Gondwana,” Gondwana Research, Vol. 7, No. 1, 2004, pp. 31-41. http://dx.doi.org/10.1016/S1342-937X(05)70304-X
[3]	H. Miyamachi, H. Murakami, T. Tsutsui, S. Toda, T. Minta and M. Yanagisawa, “A Seismic Refraction Experiment in 2000 on the Mizuho Plateau, East Antarctica (JARE-41),” Antarctic Record, Vol. 45, 2001, pp. 101-147.
[4]	T. Tsutsui, H. Murakami, H. Miyamachi, S. Toda and M. Kanao, “P-Wave Velocity Structure of the Ice Sheet and the Shallow Crust beneath the Mizuho Traverse Routes, East Antarctica, from Seismic Refraction Analysis,” Polar Geoscience, Vol. 14, 2001, pp. 195-211.
[5]	K. Yanai and S. Kaminuma, “Measurement of Gravity along the Traverse Routes Syowa-South Pole,” JARE Special Scientific Report, Vol. 2, 1971, pp. 131-150.
[6]	T. Nagao and K. Kaminuma, “Gravity Survey in the Mizuho Plateau,” JARE Data Reports, Vol. 132, 1988, pp. 1-32.
[7]	K. Kamiyama, T. Furukawa, H. Maeno, T. Kishi and M. Kanao, “Glaciological Data Collected by the 33rd Japanese Antarctic Research Expedition in 1992,” JARE Data Reports, Vol. 194,1994, pp. 1-67.
[8]	T. Higashi, M. Kanao, H. Motoyama and T. Yamanouchi, “Gravity Observations along the Traverse Routes from Syowa Station to Dome Fuji Station, East Antarctica,” Polar Geoscience, Vol. 14, 2001, pp. 226-234.
[9]	A. Ikami, K. Ito, K. Shibuya and K. Kaminuma, “Deep Crustal Structure along the Profile between Syowa and Mizuho Stations, East Antarctica,” Memoirs of National Institute of Polar Research, Series C, Earth Sciences, Vol. 15, 1984, pp. 19-28.
[10]	M. Kanao, K. Kamiyama and K. Ito, “Crustal Density Structure of the Mizuho Plateau, East Antarctica from Gravity Survey in 1992,” Polar Geoscience, Vol. 7, 1994, pp. 23-36.
[11]	K. Kaminuma, K. Tsukahara and S. Takemoto, “Absolute Gravity Value Measured at Syowa Station, Antarctica,” Bulletin D'Information BGI, Vol. 80, 1997, pp. 26-29.
[12]	Y. Fukuda, “Gravimetric Connection between Asuka Camp and Syowa Station, and Gravity Survey on Rundvagshetta,” Antarctic Record, Vol. 30, 1986, pp. 164-174.
[13]	K. Kaminuma, K. Abe and H. Tanaka, “Leveling and Gravity Surveys at Syowa Station, Antarctica,” Antarctic Record, Vol. 83, 1984, pp. 62-74.
[14]	K. Shibuya, “Performance Experiments of an NNSS Positioning in and around Syowa Station, East Antarctica,” Journal of Physics of the Earth, Vol. 33, No. 5, 1985, pp. 453-483. http://dx.doi.org/10.4294/jpe1952.33.453
[15]	Y. Fukuda, J. Segawa and K. Kaminuma, “Geoidal Undulation and Gravity Anomaly around the Japanese Antarctic Stations Estimated from both Satellite Altimeter Data and Surface Gravity Data,” Polar Geoscience, Vol. 4, 1990, pp. 108-118.
[16]	H. Maeno, K. Kamiyama, T. Furukawa, O. Watanabe, R. Naruse, K. Okamoto, T. Suitz and S. Uratsuka, “Using a Mobile Radio Echo Sounder to Measure Bedrock Topography in East Queen Maud Land, Antarctica,” Polar Meteorology and Glaciology, Vol. 8, 1994, pp. 149-160.
[17]	T. Kudo and T. Nagao, “Evaluation of Crustal Structure and Bedrock Topography around Mizuho Plateau, Antarctica Based on Gravity Data,” Polar Geoscience, Vol. 7, 1994, pp. 37-48.
[18]	K. Ito and A. Ikami, “Upper Crustal Structure of the Prince Olav Coast, East Antarctica,” Memoirs of National Institute of Polar Research, Series C, Earth Sciences, Vol. 15, 1984, pp. 13-18.
[19]	W. A. Heiskanen and H. Moritz, “Physical Geodesy,” Freeman, San Francisco, 1967, 364 pages.
[20]	M. Talwani, J. L. Worzel and M. Landisman, “Rapid Gravity Computations for Two Dimensional Bodies with Application to the Mendicino Submarine Fracture Zone,” Journal of Geophysical Research, Vol. 64, No. 1, 1959, pp. 49-59. http://dx.doi.org/10.1029/JZ064i001p00049