ARCMH25: a hybrid seismic–isostatic approach for Moho structure and density contrast estimation in the Arctic

Abstract This study introduces ARCMH25, a high-resolution hybrid Moho model that combines gravimetric and seismic data to estimate two key constituents of the Mohorovičić discontinuity (Moho): Moho Depth (MD), Moho Density Contrast (MDC), along with their associated uncertainties. The model provides 1° × 1° resolution across the Arctic region, including both the Arctic Plate and adjacent oceanic zones, covering latitudes from 60°N to 90°N and longitudes from 180°W to 180°E. ARCMH25 employs a weighted least-squares inversion that integrates multiple observational constraints, including Vening Meinesz–Moritz (VMM) isostatic estimates such as the gravimetric MD-MDC product, gravimetric-seismic MDC, and seismic MDs from the Earth Crustal Model 1 (ECM1). This integrated approach enables simultaneous estimation of MD and MDC, while also providing spatially variable uncertainty fields. Model results show significant lateral variation in MD, ranging from 10 to 20 km beneath the central Arctic Ocean to 50–60 km under continental interiors and Greenland. Similarly, MDC values vary from 100 to 200 kg/m 3 in the oceanic regions to 500–600 kg/m 3 over continents and Greenland. The model also quantifies uncertainty, with MD errors below 2 km in oceanic areas and up to 6 km on land, while MDC uncertainties remain under 50 kg/m 3 offshore and increase to approximately 90 kg/m 3 in continental regions. Comparisons with existing models demonstrate ARCMH25’s enhanced sensitivity and resolution, especially in tectonically transitional zones. The model effectively captures lithospheric variability across ocean basins, continental shields, and rifted margins, providing new insights into Arctic geodynamics. Moreover, the ARCMH25 framework is adaptable and can be applied to other seismically under-sampled regions for crustal and tectonic studies.