利用多元回归分析反演西南印度洋区域海底地形

针对海底地形与重力异常和重力异常垂直梯度在相应频段呈现强线性相关的特点,引入多元回归分析技术,提出并详细推导了联合多元重力数据的海底地形建模方法。然后,在西南印度洋SWIR(Southwest India Ridge)所在部分海域开展了海底地形反演试验及地形地貌分析研究。试验结果表明:6种海深模型中,基于多元回归分析技术构建的海深模型(BDVG模型)检核精度最高,相较于S&S V18.1模型和ETOPO1模型精度分别提高了11.51%和57.81%左右;2000 m以上水深海域,各个海深模型的检核精度较高,相对误差波动较小,反映了深海海域具有良好的反演效果;地形起伏剧烈海域或者浅海海域,BDVG海深模型,相较于以重力异常和重力异常垂直梯度作为单一输入源建立的BDG模型和BVGG模型相对误差及相对误差波动变化较小,反映了BDVG模型拥有更好的稳定性,从而体现了联合反演的必要性和优势。Indomed FZ—Gallieni FZ上唯一轴部缺失裂谷洋脊段(27洋脊段)目前属于岩浆供应充足阶段,构造作用的海底扩张对其影响较小;同时由于对称裂离方式影响,27洋脊段沿轴南北对称分布有地形隆起。

Predicting bathymetry by applying multiple regression analysis in the Southwest Indian Ocean Region

Considering the fact that the sea floor topography and gravity anomaly or vertical gravity gradient anomaly show strong linear correlation in the corresponding frequency bands, the method based on using multivariate regression analysis technique to combine multi-gravity data to construct the seafloor model was proposed. Then, the inversion test and analysis were carried out in the part of SWIR(Southwest India Ridge) in the Southwest Indian Ocean. The results showed that the bathymetry model (BDVG model) based on multiple regression analysis has the highest accuracy compared with other models, which is 11.51% and 57.81% higher than the S&S V18.1 model and ETOPO1 model respectively. The accuracy of each bathymetry model is higher, and the relative error fluctuation is small where the water depth is above 2000 m, reflecting the good inversion effect in the deep sea area. In places where the seafloor is fluctuated drastically or in shallow seaarea, BDVG model has less variation in relative error and relative error fluctuation than BDG model and BVGG model established by gravity anomaly and vertical gravity gradient anomaly as a single input source, reflecting the BDVG model has better stability and the necessity and advantage of joint inversion. The only shaft-deficient rift oceanic ridge section (27 oceanic ridge section) on the Indomed FZ-Gallieni FZ is currently in the stage of sufficient magma supply, and the seafloor expansion has less influence on it. At the same time, due to the influence of the symmetric splitting, several rises are symmetrically distributed along the north and south of the axis.