Break-up spots: Could the Pacific open as a consequence of plate kinematics?

Abstract

The South Central Pacific is the location of an abnormal concentration of intraplate volcanism. Noting that this volcanism is present from the Kermadec Tonga trench to the Easter microplate and forms a wide east-west channel, we propose to explain its occurrence in relation to the Pacific plate geometry and kinematics. We construct 2D numerical models of stress and strain within the Pacific plate using its velocity field and boundary conditions. The models indicate a shear band, associated to a change from compressional stresses to the south to tensional stresses to the north, which develop after 10 Myr between the Australian plate corner and the Easter microplate. We propose that the Central Pacific intraplate volcanism is related to this process, and may represent the first step of a future plate re-organization which will eventually break the Pacific plate in a southern and a northern plate due to intraplate stresses. Present-day intraplate volcanism would define break up spots of the future border.