Skip to main content


We’d like to understand how you use our websites in order to improve them. Register your interest.

GPS/Acoustic seafloor geodetic observation: method of data analysis and its application


We have been developing a system for detecting seafloor crustal movement by combining kinematic GPS and acoustic ranging techniques. A linear inversion method is adopted to determine the position of seafloor stations from coordinates of a moving survey vessel and measured travel times of acoustic waves in seawater. The positioning accuracy is substantially improved by estimating the temporal variation of the acoustic velocity structure. We apply our method to the ranging data acquired at the seafloor reference point, MYGI, located off Miyagi Prefecture, in northeast Japan, where a huge earthquake is expected to occur in the near future. A time series of horizontal coordinates of MYGI obtained from seven campaign observations for the period 2002–2005 exhibits a linear trend with a scattering rms of about 2 cm. A linear fit to the time series gives an intraplate crustal velocity of more than several centimeters per year towards the WNW, which implies strong interplate coupling around this region. The precision of each campaign solution was examined at MYGI and other seafloor reference points along the Nankai Trough through comparison of independent one-day subset solutions within the campaign. The resultant repeatability looks to be well-correlated with the temporal and spatial stability of the acoustic velocity structure in the seawater depending on the region as well as the season.


  1. Altamimi, Z., P. Sillard, and C. Boucher, ITRF2000: A new release of the International Terrestrial Reference Frame for earth science applications, J. Geophys. Res., 107(B10), 2214, doi:10.1029/2001JB000561, 2002.

  2. Asada, A. and T. Yabuki, Centimeter-level positioning on the seafloor, Proc. of the Japan Academy, 77, Ser. B, 7–12, 2001.

  3. Chadwell, C. D., Shipboard towers for Global Positioning System antennas, Ocean Engineering, 30, 1467–1487, 2003.

  4. Chadwell, C. D., F. N. Spiess, J. A. Hildebrand, L. E. Young, G. H. Purcell, and H. Dragert, Deep-sea geodesy: Monitoring the ocean floor, GPS World, 9, 44–55, 1998.

  5. Chadwell, C. D., F. N. Spiess, J. A. Hildebrand, and H. Dragert, Seafloor geodetic evidence of episodic spreading 25 km east of the Juan de Fuca Ridge, EOS. Trans. AGU, 83, Fall Meet. Suppl., Abst., T22A–1130, 2002.

  6. Colombo, O. L. and A. G. Evans, Precise, decimeter-level differential GPS over great distances at Sea and on Land, Proceedings ION GPS-98, Nashville, Tennessee, 1998.

  7. Colombo, O. L., A. G. Evans, M. I. Vigo-Aguiar, J. M. Ferrandiz, and J. J. Benjamin, Long-baseline (>¹000 km), sub-decimeter kinematic positioning of buoys at sea, with potential application to deep sea studies, Proc. of ION GPS2000, Salt Lake City, U.S.A., 2000.

  8. Colombo, O. L., A. G. Evans, M. Ando, K. Tadokoro, K. Sato, and T. Yamada, Speeding up the estimation of floated ambiguities for subdecimeter kinematic positioning at sea, Proceedings ION GPS-2001, Salt Lake City, Utah, 2001.

  9. Del Grosso, V. A., New equation for the speed of sound in natural water (with comparison to other equations), J. Acoust. Soc. Am., 56(4), 1084–1091, 1974.

  10. DeMets, C., R. G. Gordon, D. F. Argus, and S. Stein, Effect of recent revisions to the geomagnetic reversal time scale on estimates of current plate motions, Geophys. Res. Lett., 21, 2191–2194, 1994.

  11. Fujita, M., Seafloor geodetic observation—GPS/acoustic combination technique, HydroInternational, 7, 41–43, 2003.

  12. Fujita, M., T. Ishikawa, M. Sato, M. Mochizuki, M. Katayama, S. Toyama, T. Yabuki, A. Asada, and O. L. Colombo, Seafloor geodetic observation along the major trenches around Japan—Focusing on results at off- Miyagi area, EOS Trans. AGU, 85(47), Fall Meet. Suppl., Abstract G41A-06, 2004a.

  13. Fujita, M., M. Sato, and T. Yabuki, Development of seafloor positioning software using inverse method, Techn. Rep. Hydrogr. Oceanogr., 22, 50–56, 2004b (in Japanese).

  14. Fukuda, Y., Precise determination of local gravity field both the satellite altimeter data and the surface gravity data, Bull. Ocean Res. Inst., Univ. Tokyo, 133 pp, 1990.

  15. Funakoshi, M., H. Fujimoto, A. Sweeney, A. Kuwano, R. Hino, S. Miura, and Y. Osada, GPS/Acoustic submarine positioning using a small buoy in the subduction zone off northeastern Japan, Abstr. Joint Meet. Earth Planet. Sci., J062–001, 2005.

  16. Gagnon, K., C. D. Chadwell, E. Norabuena, Measuring the onset of locking in the Peru-Chile trench with GPS and acoustic measurements, Nature, 434, 205–208, 2005.

  17. Hatanaka, Y., T. Iizuka, M. Sawada, A. Yamagiwa, Y. Kikuta, J. M. Johnson, and C. Rocken, Improvement of the Analysis Strategy of GEONET, Bull. Geogr. Surv. Inst., 49, 11–37, 2003.

  18. Ishikawa, T. and M. Fujita, Inverse method and precision improvement for seafloor positioning, Rep. Hydrogr. Oceanogr. Res., 41, 27–34, 2005 (in Japanese with an English abstract).

  19. Jackson, D. D., The use of a priori data to resolve nonuniqueness in linear inversion, Geophys. J. Roy. Astr. Soc., 57, 137–157, 1979.

  20. Kawai, H, Hydrography of the Kuroshio Extension, in Kuroshio—Its Physical Aspects, edited by H. Stommel and K. Yoshida, University of Tokyo Press, 517 pp., 1972.

  21. Matsumoto, K., T. Takanezawa, and M. Ooe, Ocean tide models developed by assimilating TOPEX/POSEIDON altimeter data into hydrodynamical model: a global model and a regional model around Japan, J. Oceanogr., 56, 567–581, 2000.

  22. Matsu’ura, M., Bayesian estimation of hypocenter with origin time eliminated, J. Phys. Earth, 32, 469–483, 1984.

  23. Miura, S., T. Sato, A. Hasegawa, Y. Suwa, K. Tachibana, and S. Yui, Strain concentration zone along the volcanic front derived by GPS observations in NE Japan arc, Earth Planets Space, 56, 1347–1355, 2004.

  24. Mochizuki, M., M. Sato, M. Katayama, T. Yabuki, Z. Yoshida, and A. Asada, Construction of seafloor geodetic observation network around Japan, Recent Advances in Marine Science and Technology, 2002, 591–600, 2003.

  25. Mochizuki, M., M. Fujita, M. Sato, Z. Yoshida, M. Katayama, T. Yabuki, and A. Asada, Repeated trials of seafloor geodetic observation around Japan, Recent advances in marine science and technology, 2004, 11–18, 2005.

  26. Obana, K., H., Katao, and M. Ando, Seafloor positioning system with GPS-acoustic link for crustal dynamics observation—a preliminary result from experiments in the sea, Earth Planets Space, 52, 415–423, 2000.

  27. Osada, Y., H. Fujimoto, S. Miura, A. Sweeney, T. Kanazawa, S. Nakao, S. Sakai, J. A. Hildebrand, and C. D. Chadwell, Estimation and correction for the effect of sound velocity variation on GPS/Acoustic seafloor positioning: An experiment off Hawaii Island, Earth Planets Space, 55, e17–e20, 2003.

  28. Sagiya, T., Interplate coupling in the Tokai District, Central Japan, deduced from continuous GPS data, Geophys. Res. Lett., 26, 2315–2318, 1999.

  29. Sato, M. and M. Fujita, Effects of sound velocity profiles in the seafloor geodetic observation, Techn. Rep. Hydrogr. Oceanogr., 22, 42–49, 2004 (in Japanese).

  30. Sengoku, A., A plate motion study using Ajisai SLR data, Earth Planets Space, 50, 611–627, 1998.

  31. Spiess, F. N., Suboceanic geodetic measurements, IEEE Trans. Geosci. Remote Sens., 23, 502–510, 1985.

  32. Spiess, F. N. and J. A. Hildebrand, Employing geodesy to study temporal variability at a mid-ocean ridge, EOS Trans. AGU, 76, 451, 455, 1995.

  33. Spiess, F. N., C. D. Chadwell, J. A. Hildebrand, L. E. Young, G. H. Purcell, Jr., and H. Dragert, Precise GPS/Acoustic positioning of seafloor reference points for tectonic studies, Phys. Earth. Planet. Inter., 108, 101–112, 1998.

  34. Suwa, Y., S. Miura, A. Hasegawa, T. Sato, and K. Tachibana, Spatiotemporal change of interplate coupling in the Northeastern Japan subduction zone, J. Seismol. Soc. Jpn., 56, 471–484, 2004 (in Japanese with an English abstract).

  35. Tadokoro, K., R. Ikuta, M. Ando, T. Okuda, S. Sugimoto, K. Takatani, and K. Yada, Repeated observation of sea-floor deformation at Kumano Basin, Japan (2), Abstr. Joint Meet. Earth Planet. Sci., J062–007, 2005.

  36. Toyama, S., Analysis for acoustic data in sea bottom geodetic observation, Techn. Rep. Hydrogr. Oceanogr., 21, 67–72, 2003 (in Japanese).

  37. Wessel, P. and W. H. F. Smith, Free software helps map and display data, EOS Trans. AGU, 72, 441, 445–446, 1991.

  38. Yada, K., R. Ikuta, M. Ando, T. Okuda, K. Tadokoro, M. Kuno, S. Sugimoto, and K. Takatani, Spatial variations in acoustic velocity at Kuroshio region for the accurate ocean-bottom positioning, EOS Trans. AGU, 85(47), Fall Meet. Suppl., Abstract G21A–0147, 2004.

  39. Yamada, T., M. Ando, K. Tadokoro, K. Sato, T. Okuda, and K. Oike, Error evaluation in acoustic positioning of a single transponder for seafloor crustal deformation measurements, Earth Planets Space, 54, 871–881, 2002.

  40. Xu, P., M. Ando, and K. Tadokoro, Precise, three-dimensional seafloor geodetic deformation measurements using difference techniques, Earth Planets Space, 57, 795–808, 2005.

Download references

Author information



Corresponding author

Correspondence to Masayuki Fujita.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Fujita, M., Ishikawa, T., Mochizuki, M. et al. GPS/Acoustic seafloor geodetic observation: method of data analysis and its application. Earth Planet Sp 58, 265–275 (2006).

Download citation

Key words

  • GPS/Acoustic
  • seafloor geodetic observation
  • linear inversion
  • Off Miyagi
  • intraplate deformation