A new approach to assess isostatic compensation of topography in continental domain from GOCE gravity gradients

• Published in: Geophysical Journal International
• Main Authors: Cadio, Cecilia, Saraswati, Anita, Cattin, Rodolphe, Mazzotti, Stephane
• Other Authors: Géosciences Montpellier, Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2016
• Subjects: Satellite geodesy; Gravity anomalies and Earth structure; Continental margins: convergent; North America; Numerical approximations and analysis; [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph]; [SDE.MCG]Environmental Sciences/Global Changes; Canada; Northwest Territories; Yukon; Yukon Plateau; Yakutat; Alaska
• Online Access: https://hal.science/hal-01467540; https://hal.science/hal-01467540/document; https://hal.science/hal-01467540/file/cadioGJI2016.pdf; https://doi.org/10.1093/gji/ggw281

International audience Estimating how topography is maintained provides insights into the different factors responsible for surface deformations and their relative roles. Here, we develop a new and simple approach to assess the degree of isostatic compensation of continental topography at regional scale from GOCE gravity gradients. We calculate the ratio between the radial gradient observed by GOCE and that calculated from topography only. From analytical and statistical formulations, simple relationships between this ratio and the degree of compensation are obtained under the Airy–Heiskanen isostasy hypothesis. Then, a value of degree of compensation at each point of study area can be easily deduced. We apply our method to the Alaska-Canada Cordillera and validate our results by comparison with a standard isostatic gravity anomaly model and additional geophysical information for this area. Both our GOCE-based results and the isostatic anomaly show that Airy–Heiskanen isostasy prevails for the Yukon Plateau whereas additional mechanisms are required to support topography below the Northwest Territories Craton and the Yakutat collision zone.