Abstract
Different kinematic models have been proposed for the triple junction between the North American, Cocos and Caribbean plates. The two most commonly accepted hypotheses on its driving mechanism are (a) the North American drag of the forearc and (b) the Cocos Ridge subduction push. We present an updated GPS velocity field which is analyzed together with earthquake focal mechanisms and regional relief. The two hypotheses have been used to make kinematic predictions that are tested against the available data. An obliquity analysis is also presented to discuss the potential role of slip partitioning as driving mechanism. The North American drag model presents a better fit to the observations, although the Cocos Ridge push model explains the data in Costa Rica and Southern Nicaragua. Both mechanisms must be active, being the driving of the Central American forearc towards the NW analogous to a push-pull train. The forearc sliver moves towards the west-northwest at a rate of 12–14 mm/yr, being pinned to the North American plate in Chiapas and western Guatemala, where the strike-slip motion on the volcanic arc must be very small.
Highlights
As an alternative model to explain the north-westward drift of the forearc sliver the slip partitioning in the subduction was proposed[8]
This paper is a comprehensive view of the Central America forearc kinematics from Chiapas to Costa Rica considering the most commonly accepted hypotheses on its driving mechanism (North American Drag or pull, drag hypothesis (DH) vs Cocos Ridge Push, push hypothesis (PH)), discussing the potential role of the slip partitioning at the subduction interface
In the view of the available data we propose a coeval push-pull driving mechanism for the motion of the Central America forearc in the context of the North American – Caribbean – Cocos triple junction
Summary
In one of the first proposals it is suggested that the relative drift of the Caribbean plate to the east gave rise to the formation of N-S grabens in Honduras while southern Guatemala and western Honduras remained pinned to North America[1] This basic model, which did not consider the existence of a forearc sliver yet, was refined, suggesting the existence of a weakness zone along the Volcanic Arc that facilitates the displacement of a forearc sliver dragged laterally, or pulled, by the North American plate motion towards the Northwest[2,3]. This paper is a comprehensive view of the Central America forearc kinematics from Chiapas to Costa Rica considering the most commonly accepted hypotheses on its driving mechanism (North American Drag or pull, DH vs Cocos Ridge Push, PH), discussing the potential role of the slip partitioning at the subduction interface. In the view of the available data we propose a coeval push-pull driving mechanism for the motion of the Central America forearc in the context of the North American – Caribbean – Cocos triple junction
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
