Natural Resources CanadaGovernment of Canada
 
 Français ÿ  Contact us ÿ  Help ÿ  Search ÿ  Canada site
 ESS Home ÿ  Priorities ÿ  Products &
 services
ÿ  About the
 Sector
ÿ  Site map
Satellite image of Canada
Natural Resources Canada
Geodynamics
.Home
.Overview
Earthquake processes
.Overview
.Episodic Tremor and Slip (ETS)
.Earthquake cycle
.Cascadia Subduction Zone
.Cascadia Subduction Zone in action
.Mega-thrust earthquakes
.North Cascadia margin deformation from GPS measurements
.Measuring crustal motions in coastal British Columbia with continuous GPS
.Postglacial rebound at the Northern Cascadia Subduction Zone
GPS/WCDA
.Overview
.Absolute gravity
.Monumentation
.WCDA site logs and data
.Map
Global change
.Overview
.Antarctic ice sheet balance
.Ice sheet modelling
.Mid-continent tilt project
Earthquake information
.Earthquake Information - Western Canada
.Earthquakes Canada
Related links
.GPS/GNSS links
.GSC Pacific (Sidney)
ÿ


Geological Survey of Canada
Geological Survey of Canada


Proactive disclosure


Print version Print versionÿ
ÿStrong and safe communities
Natural Resources Canada > Earth Sciences Sector > Priorities > Strong and safe communities > Geodynamics
Geodynamics
Simplified subduction thrust earthquake cycle

The subduction-thrust earthquake cycle can be simplified into two stages:


1. Interseismic period or between earthquakes (100's of years)

Interseismic Period

  • Plate convergence is on-going but the two plates are locked over some width of the subduction thrust fault, resulting in both uplift and horizontal shortening of the overlying plate margin;
  • the inland extent of the deformation and the location of the areas of maximum deformation are determined by the extent and the location of the locked zone; conversely, the width and location of the locked or seismogenic zone can thus be constrained from the patterns of surface deformation.

2. Coseismic period or earthquake rupture (a few minutes)

Coseismic period

  • once the accumulating stress exceeds the strength of the fault, the locked zone fails and a great earthquake occurs;
  • during the rupture, stored elastic strain is released resulting in coseismic subsidence & horizontal extension in those region where slow uplift & horizontal shortening had accumulated.

2006-04-26Important notices