THREE-DIMENSIONAL SEISMIC STRUCTURE OF THE CRUST AND UPPER MANTLE BENEATH THE OROGENIC BELTS IN SOUTHERN HOKKAIDO, JAPAN
THREE-DIMENSIONAL SEISMIC STRUCTURE OF THE CRUST AND UPPER MANTLE BENEATH THE OROGENIC BELTS IN SOUTHERN HOKKAIDO, JAPAN
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日本北海道南部造山带下地壳和上地幔的三维地震结构
DOI：
10.4294/jpe1952.30.87
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发表时间：
1982
期刊：
影响因子：
--
通讯作者：
T. Takanami
中科院分区：
文献类型：
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作者：
T. Takanami
利用AKI和Lee(1976)发展的方法，利用千岛弧线和日本弧线交界处附近的日达卡山脉及其周围的11个台站记录的50个地方地震的P波到达时间数据，进行了反演，以构建三维结构。震源深度约为30至160公里。目前的分析揭示了日达卡地区地壳和上地幔结构的横向不均质性。在日达卡山脉西侧之下，上地幔出现了一个明显的、约束良好的低速带，而高速带则被认为存在于该山脉的中部和东部之下。这两个带都与日中山脉的轴线平行。这些带状构造延伸到至少90公里的深度。这种上地幔速度差异可以用鄂霍次克海与欧亚板块碰撞的影响来解释。尽管该造山带之下没有明确的岩石圈-地温圈边界，但区域速度变化与该造山带内的一般地质特征有很好的相关性。
P-wave arrival time data, collected from 50 local earthquakes recorded at 11 stations located in and around the Hidaka range, near the junction between the Kuril and the Japan arcs, were inverted to construct the three-dimensional structure utilizing a method developed by AKI and LEE (1976). Hypocenter depths ranged from approximately 30 to 160km. The present analysis reveals the lateral heterogeneities in the structure of the crust and upper mantle beneath the Hidaka district. A distinct and well-constrained low-velocity zone in the upper mantle appears beneath the western side of the Hidaka range, while the high-velocity zone is suggested to be present under the central and eastern side of the range. Both zones are parallel to the axis of the Hidaka range. These zonal structures extend to a depth of at least 90km. Such a velocity contrast in the upper mantle may be explained by the effect of the collision between the Okhotsk Sea and the Eurasian plates. Although there is no clear lithosphereasthenosphere boundary beneath this orogenic belt, the regional velocity variations correlate well with the general geological features within the belt.