Upper mantle P wave velocity structure and transition zone thickness beneath the Arabian Shield
Upper mantle P wave velocity structure and transition zone thickness beneath the Arabian Shield
复制标题
阿拉伯地盾下上地幔 P 波速度结构和过渡带厚度
DOI：
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
H. Gurrola
中科院分区：
文献类型：
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作者：
M. Benoit;A. Nyblade;J. VanDecar;H. Gurrola
我们使用 P 波断层扫描和接收函数分析对阿拉伯地盾下方上地幔的热异常性质进行新的限制。在上地幔中发现了广泛的低速异常，其特征是具有较强的横向速度梯度，峰峰值异常至少为 4-6%，从红海向东延伸到地盾内部。速度最低的是红海附近地区，该地区的海拔比阿拉伯地盾其他地方高出 1 公里多。我们推断，阿拉伯地盾下方存在较大的横向温度变化，这与红海附近的较高海拔有关。从 410 公里和 660 公里间断处进行的 P 到 S 转换的接收函数堆栈并不表明过渡带变薄，这表明广泛的低速异常可能仅限于比 410 公里浅的深度。
We use P wave tomography and receiver function analysis to place new constraints on the nature of the thermal anomaly in the upper mantle beneath the Arabian Shield. A broad, low velocity anomaly is found in the upper mantle characterized by a strong lateral velocity gradient, with a peak to peak anomaly of at least 4–6% extending from the Red Sea eastward into the interior of the shield. The lowest velocities are found under the region adjacent to the Red Sea where elevations are more than 1 km higher than elsewhere in the Arabian Shield. We infer that large lateral temperature variations exist beneath the Arabian Shield associated with the higher elevations near the Red Sea. Receiver function stacks of P to S conversions from the 410 and 660 km discontinuities do not indicate thinning of the transition zone, suggesting that the broad, low velocity anomaly is likely confined to depths shallower than 410 km.