## Plate Motion Calculator

This "Plate Motion Calculator" calculates the relative and absolute plate motion direction and speed at any point on the earth. Plate models used in this site describe "geological current" plate motions, i.e.  million years averaging velocities. The prototype of web-based plate motion calculator was developed by K. Tamaki. This calculator is a revised version by K. Okino using perl-CGI script.

New!  MORVEL and NNR-MORVEL are available now!  2012

Method of Calculation: Select plate motion model, plate (or plates) and input latitude and longitude of the point, then press the "Execute calculation" button.

plate geometries for NUVEL models(left) and for MORVEL (right, figure from DeMets et al., 2010)

Plate Model: (see references below)

#### Longitude[deg]:(East: positive, West: negative (ex. -116.5))

References of Models:

NUVEL-1:(relative motion, Pacific plate fixed)

DeMets, C., R. G. Gordon, D. F. Argus, and S. Stein, Current plate motions, Geophys. J. Int., 101, 425-478, 1990.

NUVEL-1A:(relative motion, Pacific plate fixed)

DeMets. C., R. G. Gordon, D. F. Argus, and S. Stein, Effect of recent revisions to the geomagnetic reversal time scale on estimate of current plate motions, Geophys. Res. Lett., vol. 21, no. 20, 2191-2194, 1994.

Please note that the model parameters for Philippine Sea Plate are based on Seno et al. (JGR, 1993)

Please note that the velocity calculated based on NUVEL-1 and NUVEL-1A may be 4.5% and <2% faster than those measured by space geodetic methods by using VLBI/SLR (Gordon, Nature 1993)

NNR-NUVEL-1:(absolute plate motion, no-net rotation)

Argus D.F., R.G. Gordon, No-net-rotation model of current plate velocities incorporating plate motion model NUVEL-1. Geophys. Res. Lett. (18) 2039-2042, 1991.

NNR-NUVEL-1A:(absolute plate motion, no-net rotation)

DeMets. C., R. G. Gordon, D. F. Argus, and S. Stein, Effect of recent revisions to the geomagnetic reversal time scale on estimate of current plate motions, Geophys. Res. Lett., vol. 21, no. 20, 2191-2194, 1994.

HS3-NUVEL-1A:(absolute plate motion, relative to hotspot frame)

Gripp, A.E., and Gordon, R.G., Young tracks of hotspots and current plate velocities, Geophys. J. Int., 150, 321-361, 2002.

MORVEL: (new relative motion model for 25 tectonic plates, spreading rates and fault azimuths are used to determine the motions of 19 plates, and GPS station velocites and azimuthal data for 6 smaller plates with little or no connection to the mid-ocean ridges)

DeMets, C., R. G. Gordon, and D. F. Argus, Geologically current plate motions, Geophys. J. Int., 181, 1-80, 2010.

NNR-MORVEL: (absolute plate motion, no-net rotation, for MORVEL 25 plates and Bird(2003) 's 31 plates)

Argus, D.F., Gordon, R.G> and DeMets, C. Geologically curren motion of 56 plates relative to the no-net rotation reference frame, Geochemistry, Geophysics, Geosystems , 12, doi:10.1029/2011GC00375., 2011.

Bird, P. An updated digital model of plate boundaries, Geochemisty, Geophysics, Geosystems, 4, 1027, doi:10.1029/2001GC000252, 2003.

Used Equation:

• rotation vector
• MƒÖF= MƒÖP - FƒÖP = (ƒÖx, ƒÖy, ƒÖz)
• rotation pole
• plat = atan(ƒÖz / sqrt (ƒÖx*ƒÖx+ƒÖy*ƒÖy))
• plon = atan(ƒÖy/ƒÖx)
• rotation rate
• rate = sqrt(ƒÖx*ƒÖx+ƒÖy*ƒÖy*+ƒÖz*ƒÖz)
• velocity at a point (tlat,tlon)
• Vew = radius * cos (tlat)*rate*(sin(plat)-cos(plat)*tan(tlat)*cos(plon-tlon))
• Vns = radius * rate * cos(plat)*sin(tlon-plon)
• Velocity = sqrt (Vew*Vew + Vns*Vns)
• Direction = atan(Vew/Vns)

Last revised : 19 Jun, 2013, bug report to okino at aori.u-tokyo.ac.jp