Ground motion information and field reports have become available from the magnitude 6.3 Mw earthquake that caused extensive damage to Christchurch, New Zealand and the surrounding areas at 12:51pm local time (23:51 UTC) on February 21, 2011.
Day 1 Report of Damage from Christchurch Earthquake (pdf file, 4.1 MB) by Kenneth J. Elwood, Associate Professor, Department of Civil Engineering, University of British Columbia. Professor Elwood happened to be in Christchurch during the earthquake for a seminar on seismic assessment of existing buildings, and continues to send observations from the damaged region.
Strong-motion records are available from the Center for Engineering Strong Motion Data.
Comparing the ground motion from the Feb 2011 and the Sept 2010 earthquakes (Version 2) (pdf file, 635 KB) by Dr. Brendon Bradley, Lecturer, Civil and Natural Resources Engineering, University of Canterbury – UPDATED 02/24/2011
For information on the September 2010 Darfield Earthquake (M7.1) near Christchurh, view EERI’s Darfield Earthquake Clearinghouse