• Title/Summary/Keyword: Upward/down continuation

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Extension for Downward Continuation of the Method of "Upward Continuation of Potential Field on Spherical Patch Area" ("구면부분지역에서 퍼텐셜마당의 상향연속"의 하향연속 확장적용)

  • Na, Sung-Ho;Chung, Tae Woong;Shin, Young Hong
    • Geophysics and Geophysical Exploration
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    • v.16 no.1
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    • pp.59-62
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    • 2013
  • We formerly reported a new method for the upward continuation of potential field on spherical patch area including Earth's curvature, which has been neglected in most studies on rectangular area with flat Earth assumption. This new method is applicable to downward continuation as well by only assigning corresponding value for the ratio of two radii; $r_2/r_1$, i.e., target radius $r_2$ versus datum radius $r_1$. In addition, the inherent problem of this method due to spherical surface geometry is described, and its one possible remedy is given.

Separation-sounding Filter for Potential Data (퍼텐셜 자료의 깊이 분리)

  • Park, Yeong-Sue;Lim, Mu-Taek;Rim, Hyoung-Rae
    • Geophysics and Geophysical Exploration
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    • v.15 no.2
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    • pp.51-56
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    • 2012
  • One of the most critical and essential procedures in the interpretation of gravity and magnetic data is to separate the anomaly due to the specific geologic structure from the summation of effects from a broad variety of geologic sources, especially those of different depths. Separation of the residual anomaly from the regional field is the most simple case of the vertical separation. If the anomaly due to a layer of specific depth can be separated or the depth of the separated layer can be quantitatively determined, it may deserve the separation-sounding. We suggest a wavelength filter whose cutoff frequency is determined by log-power spectrum analysis, as a separation-sounding filter. We applied this filter both to synthetic and real gravity data acquired at Heunghae area, and compared the results with those of Jacobsen's upward continuation filter. These showed that the proposed separation-sounding filter could be a useful tool for interpretation of the vertical geologic structure by stripping the gravity effects of geologic sources down to the desired depth.