The effect of altimetry data in estimating the elastic thickness of the lithosphere in the western Pacific Ocean

Abstract

The elastic thickness of the lithosphere (Te) is a key parameter used to describe the strength of the lithosphere. It is usually estimated by a spectral analysis between gravity and topography. In previous research on the estimation of Te, altimetry data were used on both the gravity data and topography data, which could lead to deviations. The study described in this paper analyzed the effects of using gravity anomalies derived from different data sources on the estimation of Te. Taking the western Pacific region as an example, this study analyzed the impact of the repeated presence of altimetry satellite data on the calculation of the effective elastic thickness and found that if gravity anomalies and topography model both contain altimetry satellite data, they systematically overestimate effective elasticity. For a uniform area, the difference in Te can reach up to 30%. For a Te distribution, the difference can reach up to about 16%. After eliminating this effect, the effective elastic thickness of the western Pacific region was found to be 10 km, and the statistical results of the effective elastic thickness distribution showed that the effective elastic thickness of the lithosphere in most areas of the western Pacific is about 12 km. The paper shows the importance of choosing the appropriate gravity model in evaluating the elastic thickness of lithosphere in the oceans. A figure of Te at seamounts with loading ages demonstrates that Te in the western Pacific is generally distributed within the 100–300 °C isotherm depth and does not increase with loading age.

Keywords

• The elastic thickness of lithosphere
• The western Pacific Ocean
• Altimetry data
• Spectral analysis