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)

33 Responses to “Mapping quakes in Canterbury”

  • @Nathanael I wasn’t sure which way to go. I started down the storyboard path and ended up not switching. Luckily, we have John …

    @John. Nice one! ImageMagick is a brilliant. Is there anything it can’t do?

  • I’d love to see the complete (or as complete as possible) version of this. Sunday’s aftershocks have been pretty frequent.

    A more up-to-date version of the animation would be nice, too.

  • This is great. So many of us have been following the devastating events that happened in Christchurch and this really shows what happened. Thanks for taking the time and effort to put it all together.

  • Want would be really interesting is (is possible) to see how many tweets (or texts) came out of christchurch over the day and if they follow a pattern related to the earthquake activity???

  • This is great Chris, a really nice visual representation of how it ‘felt’ down here. For many the aftershocks are still a bit nerve racking, so I imagine it’s heartening to be able to literally ‘see’ them diminishing over time.

  • Thanks for the feedback everyone. I am glad that these maps helped folks understand what went on. My thoughts go out to all the people in Christchurch who have been affected by the quake.

    @Hayden I will update the maps and animation over the next day or two.

  • Phil,

    The GeoNet summary page shows the pattern of hits to their website, which follows local earthquake activity pretty well. I imagine tweets would be the same. Personally I like just looking at the McQueen’s Valley recording to get a feel for the last day in Christchurch. (Although this doesn’t give the distribution of locations.) It’s still a very “noisy” recording! One thing that shows up in your plots is the east-west line the events occur in.

  • A lovely sequence showing us what is going on with our rellies in Ch-Ch.

    Thanks 🙂

  • The times are there to see. Everybody here was too busy looking at the pretty pictures to read the information given.
    Well done, Chris.

  • Any chance of someone doing an animation with a fixed time interval of (much) less than an hour so that we can see each quake as it happens rather than an hour at a time? Any comments about the possibility that quakes may then be seen in “strings” that might be related to each other on shorter time scales???

  • @ross I am going to try and sort something out over the next couple of evenings. Bumping up the temporal resolution and extending the time period depicted are on the list.

  • Would love to see this continue into an evolving animation as the aftershocks continue and then ultimately a finished product so a true understanding of what occurred can be seen!

  • A huge thank-you from me too for taking the trouble. My daughter, who lives in Christchurch, sent me the link; until then I had been hopping between Geonet and a map of the area!

  • @Paul. That is fantastic. I just had a quick peek through the source code. Do you mind if I make a few tweaks and fire them back to you? It would be cool to make your map the subject of a post.

  • That’s a really neat site, with the animation to give an old fella like me the visuals of what’s been keeping me awke at night!

  • Chris, the maps/animation are great – really interesting to see! Keep up the good work.

  • Thanks for doing this . I live in Sumner ChCh. where we,ve been lucky so far in terms of physical damage. Out of pure nerves I try + find info after a shake + your site helps.…

  • Great work! Chris. Sad we just talked about your previous earthquake visualisation work in the conference, two days later, this one happened.

  • I would like to see a 3 dimensional map that shows the depths and magnitude. It does not need to be animated. For instance translucent different colored bubbles over lapping each other in 3d space with the ground level on top. a few locations on the surface to help with orientation. This might give a perspective of the layers and dynamics below?

  • Leave your comment here…how come there are more quakes portrayed on christchurchquakemap.co.nz than are actually stated on geonet??

  • Have the experts come to any opinion about what is happening below the earth’s crust in Canterbury? As the aftershocks appear to come closer to the surface is there a chance of a volcano?