| 講演要旨(和文) | | 海陸にまたがる地震波探査において，地震波動の相反定理が成り立つかどうかを実験調査した．まず陸上バイブレータ発震-海上ハイドロフォン受振記録と海上エアガン発震-陸上ジオフォン受振記録を比較し，両者の波形は良く一致することを確認した．次に，陸上ダイナマイト発震-海上ハイドロフォン受振記録と海上エアガン発震-陸上ジオフォン受振記録を比較し，この両記録に関しても両者の波形は良く一致することを確認した．以上より，相反定理が実験データを通じて成立することが証明された．従って，震源波形が既知であるバイブレータとエアガンの記録に最小位相変換を施せば，バイブレータ，エアガン及びダイナマイト等の異種震源の種別に依存しない共通発震記録及び受振記録の構築が，海陸横断調査において可能となる．また，海上取得データを陸上取得データによって内挿する等のデータ補間処理を通じて地震探査結果の高精度化に繋がることが期待される． |
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| | 講演要旨(英文) | | An experimental study was conducted in order to verify whether seismic reciprocity in transition-zone survey is obtained. Firstly, the comparison was made for the time-series recorded between an onshore geophone (vertical velocity) and an offshore airgun (explosive) source with these between an offshore hydrophone (pressure) and an onshore vibrator source (vertical force). Two of the waveforms were found to be very harmonious with each other. Moreover, a similar outcome was observed in a relationship of the time-series recorded between buried array of multi-component geophones (dilatation) and an offshore airgun source (explosive) with these between an offshore hydrophone (pressure) and an onshore dynamite source (explosive). The above experiments demonstrated that the seismic reciprocity in transition-zone survey was obtained. Data from different sources including vibrator, airgun and dynamite can be integrated to a full range shot- or receiver-gather from single source type. It is noted that a minimum-phase conversion should be added to data of the signature-known airgun and vibrator sources. Further studies are expected to gain more sophisticated approaches through advanced processing methods such as the data integration or interpolation using seismic reciprocity. |
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