Mapping quakes in Canterbury

By Chris McDowall 05/09/2010 33

I awoke yesterday morning to a stream of tweets and news articles reporting a massive earthquake near Christchurch. I followed the coverage throughout the day, reading the surreal accounts of everyday scenes turned upside down. Every so often an aftershock would ripple across Twitter and I would get a sense of the rhythm, if not the magnitude, of the event.

This morning I decided to try and map the data myself. I downloaded the seismic activity data from the GeoNet data portal. GeoNet is a joint geological hazard monitoring project between GNS and the Earthquake Commission. One of the great things about GeoNet is the fact that their data is freely available for researchers and members of the public to download and analyse.

Late this morning I wrote a short programme to parse the GeoNet data and generate a storyboard of maps to visualise the pattern of seismic activity for Canterbury on September 4. Each map represents one hour. The circles represent seismic events, centered on the quake’s epicenter. The larger the circle, the higher the quake’s magnitude. I have neglected to include a legend – it’s Sunday afternoon now and my dogs are begging to be walked – but the magnitudes can be inferred by examining and comparing the maps’ “largest magnitude” values.

If people are interested I can update the maps later this week to include the many aftershocks that occurred today.

UPDATE (Sunday) : John Fouhy has threaded the maps together into a cool animation. Nice!

UPDATE (Tuesday) : Paul Nicholls has created an animation of the last few days. It’s definitely worth checking out.

See the original set of quake maps below.

Seismic activity in Canterbury (Sunday, September 5)
Seismic activity in Canterbury (Saturday, September 4)

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