Very low shear wave velocity at the base of the mantle under the South Pacific Superswell
Very low shear wave velocity at the base of the mantle under the South Pacific Superswell
复制标题
南太平洋超级涌浪下地幔底部的剪切波速度非常低
DOI：
10.1016/s0012-821x(02)00918-4
复制
发表时间：
2002
影响因子：
5.3
通讯作者：
S. Tanaka
中科院分区：
文献类型：
--
作者：
S. Tanaka
利用SKKS-SKS和S(Sdiff) -SKS差分传播时间研究了南太平洋超级井地幔底部S波速度的非均质性。将SKKS-SKS和S(Sdiff) -SKS相对于初步参考地球模型（PREM）的残差与最近发表的三维横波速度模型预测的残差进行了比较。我们得到了一个能很好地解释S(Sdiff) -SKS残差的三维模型，并将该模型应用于SKKS-SKS残差的校正。校正后的SKKS-SKS残留在南太平洋超级井下仍然很大且为正值。正演模拟表明，这些残差可以由地幔最下方~ 200公里处横向范围约为500公里的5-7%的低速区来解释。虽然速度降低的幅度和异常区的厚度相互抵消，不能唯一地确定，但在地幔底部存在一个非常低的s波速度区域是一个强有力的特征。该特征靠近西南太平洋下方p -速度数据确定的超低速度带（ULVZ），位于南太平洋超级井下方2300-2700公里深处的下地幔2-3%低s -速度体下方。
S-wave velocity heterogeneity at the base of the mantle beneath the South Pacific Superswell has been examined using SKKS–SKS and S(Sdiff)–SKS differential travel times. The residuals of SKKS–SKS and S(Sdiff)–SKS with respect to the preliminary reference Earth model (PREM) are compared to the residuals predicted using recently published three-dimensional S-wave velocity models. We have obtained a three-dimensional model that explains the S(Sdiff)–SKS residuals well, and applied this model to the correction of the SKKS–SKS residuals. The corrected SKKS–SKS residuals beneath the South Pacific Superswell remain large and positive. Forward modeling reveals that these residuals can be accounted for by a 5–7% low velocity region with a lateral extent of about 500 km in the lowermost ∼200 km of the mantle. Although the magnitude of the velocity reduction and the thickness of the anomalous region trade off against one another and cannot be uniquely determined, the existence of a very low S-wave velocity region at the base of the mantle is a robust feature. This feature lies close to the ultra-low velocity zone (ULVZ) identified by P-velocity data beneath the southwestern Pacific, and is located just below a 2–3% low S-velocity body in the lower mantle at depths of 2300–2700 km beneath the South Pacific Superswell.
H.264编码器DCT的硬件实现及其评估
DOI：
--
发表时间：
2009
期刊：
影响因子：
--
作者：
Choong Geun Lee;V. G. Moshnyaga and K. Hashimoto;宮田康治
通讯作者：
宮田康治