The 21st Century has seen the occurrence of 17 great earthquakes (Mw>8), including some of the largest earthquakes ever recorded. Numerical modelling of the earthquakes shows that nearly half of the Earth’s surface has undergone horizontal co-seismic deformation >1 mm, with the 2004 Sumatra-Andaman earthquake dominating the global deformation field. This has important implications for both the realisation of a terrestrial reference frame and in the interpretation of regional tectonic studies based on GPS velocities.
The accumulated global deformation field shows that two regions, Australia and the north Atlantic/Arctic Ocean, have been largely undeformed by these great earthquakes, with accumu lated deformations generally <0.5 mm.
The purpose of this web site is to permit the calculation of the co-seismic horizontal deformations at any location using the models published by Tregoning et al .
We derived model estimates of static co-seismic deformation using a spherical layered model [Pollitz, 1996]. Surface deformation is calculated assuming the PREM elastic stratification [Dziewonski and Anderson, 1981], with a spherical harmonic expansion from degrees 1 to 1500. Please cite Tregoning et al.  if you use this site for computations.
Enter site coordinates (e.g. -65.2, 254.34 ) to calculate the horizontal deformations at the site caused by each of the 15 great earthquakes.
Tregoning, P., R. Burgette, S.C. McClusky, S. Lejeune, H. McQueen and C.S. Watson, 2013, A decade of horizontal deformation from great earthquakes, J. Geophys. Res., 118, doi:10.1002/jgrb.50154 pdf