McKenzie and Parker: testing rigid plate motion on a sphere

What is recorded here?

McKenzie and Parker modeled rigid plates as rotations on a sphere and tested a common North Pacific rotation pole against published shallow-earthquake slip directions. A plate moving on the curved Earth cannot be represented everywhere by the same flat-map translation. McKenzie and Parker used a rotation axis to organize the relative movement of two rigid plates. Transform faults run along small circles about that axis; elsewhere the relative motion can create or consume crust. They estimated a North Pacific pole from two direction constraints, then compared predicted directions with published earthquake solutions. In a Mercator map centered on that pole, compatible slip directions become parallel, making the prediction easy to inspect. Most of the tested shallow-earthquake solutions agreed within the paper's stated angular tolerance, with local exceptions discussed explicitly. The work links different fault mechanisms to one regional motion model. It describes instantaneous kinematics, rather than the forces driving plates or a verified account of every historical and worldwide motion.

Source-linked catalogue note. A detailed explanatory guide has not yet been prepared for this entry.

Scientific scope

Approximately rigid aseismic plates on a sphere; relative motion is an instantaneous Euler rotation. Transform slip gives direction, not rate; additional spreading-rate evidence is needed. Local planar velocity circuits apply rigorously only at infinitesimal junctions; global circuits use angular velocities, not summed finite rotations. North Pacific pole is constrained by San Andreas and Kodiak directions; about 80 published shallow-earthquake solutions were tested. Published data are not newly replayed; fit uncertainties and local exceptions remain. Mercator preserves local angles, not velocities near poles. Model is explicitly instantaneous phenomenology, excludes intermediate/deep-focus earthquakes and leaves driving mechanism and plate evolution unresolved. The target covers pages 1276-1280. The original header dates the paper December 30, 1967; some catalogue metadata instead displays December 1. The assessed contribution is limited to this tectonics paper. The regional field-data analysis has not been independently reproduced here.

Read the original work

• D. P. McKenzie and R. L. Parker, The North Pacific: an Example of Tectonics on a Sphere, original Nature scan, Alberta copy
• Publisher Crossref deposit for McKenzie/Parker1967 spherical tectonics

This English explanation is an editorial reading view. It does not replace the complete original work or certify its science.

People and systems

D. P. McKenzie; R. L. Parker

Source-listed contributors to this scoped work. Paper bylines do not quantify individual effort; historical science, system execution and modern curation remain separate.