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| | Abstract | | The wedge type events were interpreted as deeply situated consolidated magma in the seismic survey of the Akinomiya geothermal area in the Akita prefecture in northern Japan. For its verification, the gravity and air-magnetic data was analyzed integrally. The cross plots of the Bouguer gravity anomaly and the air-magnetic anomaly show the regional trend which reflects the magnetic effects from the magnetization difference between basement rocks and overlying tuff rocks. By applying the formula representing the trend, the portion of magnetic anomaly reflecting only from the underground non-magnetized magma can be extracted and analyzed. The results are encouraging to assess and draw the distribution and uneven surface of the magma and the sills and intrusions as well, mainly situated on basement high areas rather than those of depression and connecting well to the areas of currently active volcanos. The results of the estimated consolidated magma thickness also fit satisfactorily in the results of seismic interpretation. |
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