1887
Volume 40, Issue 1
  • ISSN: 0812-3985
  • E-ISSN: 1834-7533

Abstract

On Aogashima Island, a volcanic island located in the southernmost part of the Izu Seven Islands Chain, vector magnetic anomalies were obtained in a helicopter-borne magnetic survey. The purpose of this study was to understand the volcanic structure of Aogashima Island in order to mitigate future disasters.

Commonly, to obtain the magnetic structure of a volcanic island, total intensity anomalies () have been used, even though they have intrinsic errors that have not been evaluated correctly.

Because the total intensity magnetic anomaly () is not a physical value, it does not satisfy Maxwell’s Equations, Laplace’s Equation, etc., and so is not suitable for any physical analyses. In addition, it has been conventionally assumed that is the same as the projected total intensity anomaly vector () for analyses of . However, the effect of the intrinsic error ( = –) on the analysis results has not been taken into account. To avoid such an effect, vector magnetic anomalies were measured so that a reliable analysis of Aogashima Island magnetization could be carried out.

In this study, we evaluated the error in and used vector anomalies to avoid this erroneous effect, in the process obtaining reliable analysis results for 3D, vector magnetization distributions. An area of less than 1 A/m magnetization was found in the south-west part of Aogashima Island at the depth of 1–2 km. Taking the location of fumarolic activity into consideration, the lower-magnetization area was expected to be the source of that fumarolic activity of Aogashima Island.

© 2009 ASEG
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2026-01-22

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References

  1. Baranov V. 1957 A New Method for interpretation of aeromagnetic maps: PSEUDO-GRAVIMENTRIC Anomalies: Geophysics 22359 383 doi:10.1190/1.1438369
    [Google Scholar]
  2. Bhattacharyya B. K. 1964 Magnetic anomalies due to prism-shaped bodies with arbitrary polarization: Geophysics 29517 531 doi:10.1190/1.1439386
    [Google Scholar]
  3. Blakely R. J. 1995, Potential theory in Gravity and Magnetic Applications: Cambridge University Press, 441p.
  4. Hughes D. S. Pondrom W. L. 1947 Computation of vertical magnetic anomalies from total magnetic field measurements: Transactions – American Geophysical Union 28193 197
     [Google Scholar]
  5. Isezaki N. 1986 Anew shipboard three component magnetometer: Geophysics 511992 1998 doi:10.1190/1.1442054
    [Google Scholar]
  6. International Association of Geomagnetism and Aeronomy (IAGA) Division V Working Group VMOD: Geomagnetic Field Modeling 2005 The 10th-Generation International Geomagnetic Reference Field: Geophysical Journal International 161561 565 doi:10.1111/j.1365-246X.2005.02641.x
    [Google Scholar]
  7. Kato H. Isezaki N. Park C. H. Kim C. H. Nakanishi M. 2007 Characteristics of crustal magnetic structure in the Tsushima (Ulleung) and Japan Basins from vector magnetic anomalies: Earth, Planets, and Space 59887 895
     [Google Scholar]
  8. Lourenco J. S. Morrison H. F. 1973 Vector Magnetic anomalies derived from measurements of a single component of the field: Geophysics 38359 368 doi:10.1190/1.1440346
    [Google Scholar]
  9. Makino M. Nakatsuka T. Okuma S. Kaneko T. 1988 Aeromagnetic Anomalies over the Izu-Oshima Volcano: Bulletin of the Volcanological Society of Japan, Second Series 33217 223
     [Google Scholar]
  10. Nabighian M. N. 1972 The analytic signal of two-dimensional magnetic bodies with polygonnal cross-section, its properties and use for automated anomaly interpretation: Geophysics 37507 517 doi:10.1190/1.1440276
    [Google Scholar]
  11. Okuma S. Makino M. Nakatsuka T. 1989 Two-layer Model Inversion of Magnetic Anomalies using Pseudogravity and Reduction to the Pole: An application to the analysis of aeromagnetic anomalies over Izu-Oshima: Geophysical Exploration (Buturi-Tansa) 4282 96
     [Google Scholar]
  12. Okuma S. Makino M. Nakatsuka T. 1994 Magnetization intensity mapping in and around Izu-Oshima volcano: Japan Journal of Geomagnetism and Geoelectricity 46541 556
     [Google Scholar]
  13. Pelto C. R. Elkin T. A. Boyd H. A. 1968 Automatic contouring of irregularly spaced data: Geophysics 34424 430
     [Google Scholar]
  14. Takada A. Oshima O. Aramaki S. Ono K. Yoshida T. Kajima K. 1992 Geology of Aogashima Volcano, Izu Islands: Bulletin of the Volcanological Society of Japan 37233 250
     [Google Scholar]
  15. Tokyo Disaster Prevention Council 1990, The reports for the property of volcanic eruption at Izu Island Arc (Aogashima): the booklet of earth science, 233–250.
  16. Ueda Y. , Kumagaya K. , Koyama K. 2008, Air borne magnetic surveys and their significaces for the monitoring of volcanic activities: Japan Geoscience Union Meeting, O220–004.
  17. Yamamoto M. Seama N. Isezaki N. 2005 Geomagnetic paleointensity over 1.2 Ma from deep-tow vector magnetic data across the East Pacific Rise: Earth, Planets, and Space 57465 470
     [Google Scholar]
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Magnetization structure of Aogashima Island using vector magnetic anomalies obtained by a helicopter-borne magnetometer
Exploration Geophysics 40, 17 (2009); https://doi.org/10.1071/EG08112
/content/journals/10.1071/EG08112
/content/journals/10.1071/EG08112
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  • Article Type: Research Article
Keyword(s): Aogashima Island; helicopter-borne vector magnetometer; vector magnetic anomalies; vector magnetization

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