A magnitude 4 earthquake is to strike Christchurch this morning - but this one will be man-made.
The "earthquake" is to strike at 11.30am, at QEII Stadium, at a depth of up to 12km.
The jolt is part of tests by the Earthquake commission into whether liquefaction-prone land in the east of the city can be repaired.
About 25 small underground explosives are to be placed up to 12 metres deep and set off to simulate an earthquake of about magnitude 4.
EQC Canterbury events manager Reid Stiven told Radio New Zealand the shaking from the earthquake will go on for about 10 seconds, and will be felt up to 10km away from the site.