Earthquakes 1963-1995; mb > 4

Stein and Wysession, 2003

INTRAPLATE

NARROW BOUNDARIES

DIFFUSE BOUNDARY ZONES

• From seismicity and current deformation patterns

Inferred plate boundaries

Gordon and Stein, 1992

Color scale:

Green & Black: Stable

Red: Unambiguous current deformation

Orange: Likely current deformation (earthquakes)

Yellow: Maybe current deformation (from plate cicuits)

relative plate velocities based on seafloor spreading rates and directions plus directions from earthquake slip vectors

NNR-NUVEL-1A

http://sps.unavco.org/crustal_motion/dxdt/dxdt.html