Abstract
The movement of the seawater across the earth's magnetic field produces a large-scale motional electric field. Using the Point Arena, California, to Hanauma Bay, Hawaii, unpowered HAW-1 cable, we have studied the geopotential across this distance to look for possible tsunami-induced fields that might have been produced following the April 1992 Cape Mendocino earthquake. We have used a ten-day interval prior to and including the earthquake as a reference for geopotential signals and for geomagnetic activity. We have also used geomagnetic data from Point Arena, Honolulu and Boulder as reference data. The results of the analyses show that there are tsunami-related effects in the cable geopotential data. These are (a) larger voltage prediction errors (residuals) for the interval following the main shock; (b) enhanced (compared to the 10d reference interval) geopotential spectral power following the main shock: two enhancements are larger than geomagnetically-induced spectral power enhancements in the same time interval; and (c) strong evidence for an ∼30 min “echo” in the cable geopotential signal following the main shock.
Similar content being viewed by others
References
Akaike, H., andYamanouchi, Y. (1962),On the Statistical Estimation of Frequency Response Function, Ann. Inst. Math.14, 23–56.
Chave, A. D., Luther, D. S., Lanzerotti, L. J., andMedford, L. V. (1992),Geoelectric Field Measurements on a Planetary Scale: Oceanographic and Geophysical Applications, Geophys. Res. Lett.,19, 1411.
Chave, A. D., andFilloux, J. H. (1985),Observation and Interpretation of the Seafloor Vertical Electric Field in the Eastern North Pacific, J. Geophys. Res.12, 793.
Chave, A. D., Filloux, J. H., Luther, D. S., Law, L. K. andWhite, A. (1989),Observations of Motional Electromagnetic Field During EMSLAB, J. Geophys. Res.94, 14153.
Chave, A. D., Thomson, D. J., andAnder, M. E. (1987),On the Robust Estimation of Power Spectra, Coherences, and Transfer Functions, J. Geophys. Res.92, 638–48.
Chave, A. D., andThomson, D. J. (1989),Some Comments on Magnetotelluric Response Function Estimation, J. Geophys. Res.94, 14,215–14,225.
Egbert, G. D., andBooker, J. R. (1989),Multivariate Analysis of Geomagnetic Array Data. 1. The Response Space, J. Geophys. Res.94, 14,227–14,247.
Egbert, G. D. (1989),Multivariate Analysis of Geomagnetic Array Data. 2. Random Source Models, J. Geophys. Res.94, 14,249–14,265.
Faraday, M. (1932),Experimental Researches in Electricity, Phil Trans. R. Soc.163.
Filloux, J. H.,Instrumentation and experimental methods for oceanic studies. InGeomagnetism, 1 (ed. J. A. Jacobs) (Academic Press 1987), 143 pp.
González, F. I., Satake, K., Boss, E. G., andMofjeld, H. O. (1995),Offshore and Edgewave Tsunami Modes Generated by the 25 April 1992 Cape Mendocino Earthquake, Pure and Appl. Geophys., this issue.
Goodman, N. R. (1957),On the Joint Estimation of the Spectrum, Cospectrum, and Quadrature Spectrum of Two-dimensional Stationary Gaussian Processes, Scientific Paper 10, Engineering Statistical Laboratory, New York Univ. (Also AD 134919, Defense Technical Information Center).
Kleiner, B., Martin, R. D., andThomson, D. J. (1979),Robust Estimates of Spectra (with discussion), J. Royal Statist. Soc.B41, 313–351.
Lanzerotti, L. J., Thomson, D. J., Meloni, A., Medford, L. V., andMaclennan, C. G. (1986),Electromagnetic Study of the Atlantic Continental Margin Using a Section of a Transatlantic Cable, J. Geophys. Res.B91, 7417–7427.
Lanzerotti, L. J., Medford, L. V., Kraus, J. S., Maclennan, C. G., andHunsucker, R. D. (1992),Measurements of Small Amplitude TIDs Using Parallel, Unpowered Telecommunications Cables, Geophys. Res. Lett.19, 253.
Lanzerotti, L. J., Sayres, C. H., Medford, L. V., Kraus, J. S., Maclennan, C. G., andThomson, D. J. (1993),Statistical Study of Induced Voltages Across Oceanic Telecommunications Cables, Proc. 1992 Solar-Terrestrial Pred. Conf.1, 224.
Larsen, J. C. (1989),Transfer Functions: Smooth Robust Estimates by Least-squares and Remote Reference Methods, Geophys. J.99, 645.
Larsen, J. C., andSanford, T. B. (1985),Florida Current Volume Transports from Voltage Measurements, Science227, 302.
Larsen, J. C. (1992),Transport of the Florida Current at 27° N Derived from Cross-stream Voltages and Profiling Data: Theory and Observations, Phil. Trans. R. Soc. Lond.A338, 169.
Lilley, F. E. M., Filloux, J. H., Mulhearn, P. J., andFerguson, L. J. (1993),Magnetic Signals from an Ocean Eddy, J. Geomagn. Geolectr.45, 403.
Meloni, A., Lanzerotti, L. J., andGregori, G. P. (1983),Induction of Currents in Long Submarine Cables by Natural Phenomena, Rev. Geophys,21, 795.
Munk, W. H., andCartwright, D. E. (1966),Tidal Spectroscopy and Prediction, Phil. Trans. R. Soc. Lond.A259, 533–581.
Oppenheimer, D., Beroza, G., Carver, G., Dengler, L., Eaton, J., Gee, L., González, F., Jayko, A., Li, W. H., Lisowski, M., Magee, M., Marshall, G., Murray, M., McPherson, R., Romanowicz, B., Satake, K., Simpson, R., Somerville, P., Stein, R., andValentine, D. (1993),Cape Mendocino, California, Earthquakes of April 1992: Subduction at the Triple Point, Science261, 433.
Prandle, D., andHarrison, A. J. (1975),Recordings of the Potential Difference across the Port Patrick-Donaghedee Submarine Cable, Rep. Inst. Oceanog. Sci. Bidston Obs.21.
Segawa, J., andToh, H. (1992),Detecting Fluid Circulation by Electric Field Variations at the Nankai Trough, Earth Planet. Sci. Letts.109, 469.
Shumway, R. H.,Applied Statistical Time Series Analysis (Prentice Hall, Englewood Cliffs, NJ 1988).
Sutarno, D., andVozoff, K. (1989),Robust M-estimation of Magnetotelluric Impedance Tensors, Exploration Geophys.20, 383–398.
Thomson, D. J. (1977),Spectrum Estimation Techniques for Characterization and Development of WT4 Waveguide, Bell System Tech. J.56, Part I, 1769–1815, Part II, 1983–2005.
Thomson, D. J. (1982),Spectrum Estimation and Harmonic Analysis, Proc. IEEE,70, 1055–96.
Thomson, D. J., andChave, A. D.,Jackknifed error estimates for spectra, coherences, and transfer functions, Ch. 2. InAdvances in Spectrun Analysis (ed. S. Haykin) (Prentice-Hall 1990).
Thomson, D. J., Lanzerotti, L. J., Medford, L. V., Maclennan, C. G., Meloni, A., andGregori, G. P. (1986),Study of Tidal Periodicities Using a Trans-Atlantic Telecommunications Cable, Geophys. Res. Lett.13, 525.
Wertheim, G. K. (1954),Studies of Electrical Potential Between Key West, Florida, and Havana, Cuba, Trans. AGU35, 872.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Thomson, D.J., Lanzerotti, L.J., Maclennan, C.G. et al. Ocean cable measurements of the tsunami signal from the 1992 Cape Mendocino earthquake. PAGEOPH 144, 427–440 (1995). https://doi.org/10.1007/BF00874376
Received:
Revised:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00874376