Christchurch NZ Earthquake

[spiderman]

libby, you do raise an interesting question...
following are some notes excised from the usgs:
earthquake.usgs.gov/earthquakes/step/explain.php see this site for a long and fascinating explanation

"In a cluster, the earthquake with the largest magnitude is called the main shock; anything before it is a foreshock and anything after it is an aftershock. A main shock will be redefined as a foreshock if a subsequent event has a larger magnitude."

.... "As a rule of thumb, we call earthquakes aftershocks if they are at a distance from the main shock’s fault no greater than the length of that fault. [though curiously, they dont have to be on the same fault, just nearby]

aftershocks can occur DECADES after the main shock. i'd have thought that was stretching things a bit. additionally, they continue for longer if the fault line was seismically quiet.

i hope that helps a little... it will be a shaky christmas; but i feel reassured in that the pressure is off the fault so it is unlikely to give rise to another very large quake.

also see www.stuff.co.nz/national/4230460/Canterbury-earthquake-trigger-identified
for an explanation of how the 7.1 earthquake was triggered.

the spiderman

[Libby]

Thanks.

[Ross]

Band Together Earthquake Concert Christchurch
Hagley Park Sat 23rd Oct

A free concert was put on by 34 New Zealand acts for the people of Christchurch. It started at 11am and went on to 8pm.
Dame Malvina Major was a guest artist at the beginning of the show but I never saw her as I was still at work and TV 3 which broadcast the concert didn't start until 12pm.
I arrived at 4:30pm and the crowd was around 2000000 making it one of the biggest concerts in NZ.
Dave Dobbyn was the 2nd last act (for those that don't know he duetted with Hayley during her last tour of NZ).

Over $17 million dollars was raised by the TV broadcast for the Quake appeal which was fantastic for a country of 4 million people.