[G04-4] Earth rotation and geodynamics IV

[G04-4-01] Actual Continuous Kinematic Model (ACKIM) of the Earth Crust based on ITRF2014

^○Hermann Drewes (Technical University Munich, Munich, Germany)

The global kinematics of the Earth crust is traditionally represented by geophysical rigid plate models (e.g. NUVEL-1A, DeMets et al. 1994) integrating their motions linearly over geologic time scales (millions of years). The present-day plate motions and deformations in boundary zones are based on these models deriving the plate rotation poles from geodetic station velocities as actual plate kinematic models (e.g. APKIM, Drewes 2009). The denser the geodetic station distribution becomes, the more different plates and inter-plate and/or intra-plate deformation zones are detected. The model PB2002 (Bird 2003) includes 52 plates (instead of 14 in NUVEL-1A) and 13 orogenic zones. But even this increasing structure does not reflect the true crustal deformation obtained from geodetic observations. Larger plates (e.g. North American, Caribbean) do not move rigidly but they are split and present significantly varying motions in different regions. Smaller plates (e.g. Peru, Puna Sierras-Pampeanas, Okhotsk) show strong regional deformations. This paper presents an actual continuous kinematic model (ACKIM) instead of a rigid plate model. Crustal motions in a global 1 deg. x 1 deg. grid are derived from ITRF2014 station velocities in a least squares collocation approach. A no-net-rotation condition with respect to horizontal motions over the entire Earth's surface is included in order to get the model consistent with Earth rotation. The model reflects much better the present-day deformations of the Earth crust than any plate kinematic model.