Earthquake at Christchurch

By Grant Jacobs 23/12/2011

(This brief report may be updated periodically.)

Geonet reports magnitude 5.8 earthquake at 1:58pm just offshore to the east of Christchurch, at a depth of 8km. This was followed by a magnitude 5.3 and just a few minutes ago (3:18pm) another aftershock that looks to be over magnitude 5. USGS is reporting both larger aftershocks to be magnitude 5.8, reporting both to be at an estimated depth of  just under 5km.


With goods falling of shelves and the general chaos that happens, this will have put a spanner in the works of anyone trying last-minute Christmas shopping in Christchurch.

Those that follow my earthquake report thread will know this is the first event over magnitude 4 in quite a while. Here’s hoping for not too much damage and that everyone is fine. Initial comments from informal sources suggest there is little major damage and no loss of life, with only one injury reported thus far.

Telecom NZ has called for mobile calls to be limited to emergency use.

An initial Police report is available, reporting ’no serious injuries or widespread damage at this stage.’

Items on #eqnz (twitter) – please note that many of these are unconfirmed (comments in square brackets are my own):

@PatrickNZ (Patrick)
All flights grounded in NZ due to evacuation of air traffic control in Chch [Other reports say flights are diverted from Christchurch, which sounds more realistic to me.]
@BreakingNZ (Breaking News)
#EQNZ ALERT — Liquefaction has begun taking place in localised areas of Christchurch.
@publicaddress (Russell Brown)
Opened a thread for our #chch Public Address people to check in and report, and for the rest of us to bring hugs: #eqnz
@JoyReidTVNZ (Joy Reid)
Can hear sirens an alarms whirring all over the city!!!
@OrionNZ (Orion New Zealand)
Some power is out in #chch after the 5.8 #eqnz. We will assess the situation & provide an update asap
@dchengnzh (Derek Cheng)
Police say initial reports following this afternoon’s earthquake indicate no serious injuries or widespread damage at this stage [Several other tweets say similar.]
@dchengnzh (Derek Cheng)
Scarborough rockface has suffered some collapse but this has been contained by the containers at the foot of the cliff.
@danaavk (Dana)
wine bottles broke, now my kitchen smells like an AA meeting
@ktflood (Katie Flood)
Dad @ CHCH airport, lots of broken glass & shaken ppl but apparently hoping to re-open at 3 acc to Civil Defence [Other reports suggest re-opening later in the day.]
@five15design (Paul Le Comte)
just had report form my lame uncle in CHCH who literally just dodged a collapsing brick wall on the sidewalk in Linwood #EQNZ #TooClose
@CERAgovtnz (CERA)
Confirming that CBD red zone is closed
That was HUGE!! Smashed widows all through our house. Power out….
@JoyReidTVNZ (Joy Reid)
House collapsed in St Martins. Major holes in the road reported on Broadhaven Avenue
@rafmanji (Raf Manji)
The filing cabinet has finally given up the ghost #eqnz

I’d suggest those wanting more to use the #eqnz search on twitter themselves. As a practical matter they’re coming in too fast for me.

The NZ Herald has some updates.

4:15pm – I have to leave this at this point. To those in Christchurch: Kia kaha

[Updated to add image, 24-Dec 10:40am.]

[Update links to USGS, 29-Sep-2013 11:05pm; thanks to Katie Cook for drawing this to my attention.]

0 Responses to “Earthquake at Christchurch”

  • Loose notes in a moment of free time:

    Some banks will be closing their offices tomorrow, e.g. Westpac reports via twitter:

    @WestpacNZ Westpac
    All #chch branches are closed tomorrow, inc. those usually open Sat. All will reopen Wed 28 Dec subject to structural engineer signoff

    Christchurch Airport has apparently just re-opened. (Unconfirmed. They’ll have a substantial backlog to get through, though.)

    Via twitter:

    @michelle74m (Michelle Maroney)
    Supposed to be feasting on paella & a Ripponvale red, instead having bbq sausage, bread and a tui beer
    [Appropriate choice of beer, perhaps? vis a vis their advertising line.]

    As per previous events, useful twitters accounts for ‘official’ information include: @CERAgovtNZ, @ChristchurchCC, @NZcivildefence and @geonet I’ve collected a few items from their tweets below.

    CERA has released an initial (& brief) statement:

    The NZ Civil Defence is up to update 4; the main additional news seem to that the National Crisis Management Centre is standing down & letting local resources manage these latest events:

    With the CDB closed, the Cathedral walkway will be closed tomorrow (via @ChristchurchCC).

    @ChristchurchCC (ChCh City Council)
    Sewer overflow into the Avon River reported, avoid contact with river/estuary for 48 hrs. City’s treatment plants working

    @OrionNZ (Orion New Zealand)
    6.15pm: Residents in #chch eastern suburbs should remain prepared for intermittent power cuts over the next few days due to #eqnz

    @AA_Traffic (AA Traffic)
    Christchurch people asked to stay off the roads unless necessary and stay away from hills

    @ChristchurchCC (ChCh City Council)
    CD says situation in the city similar to what was experienced in June in terms of damage and liquefaction

    @ChristchurchCC (ChCh City Council)
    No apparent damage to water infrastructure, Chief Medical Officer of Health not advising people to boil water at this stage.

    @christchurchlib: Libraries affected by earthquakes on Friday 23 Dec – In addition to the advertised holiday hours…

    @ChristchurchCC (ChCh City Council)
    The Lyttelton tunnel is open

  • Those familiar with my previous earthquake reports will know that I have previously noted each of the aftershocks of magnitude four or higher. I am unsure whether to continue with this or not. My aim for this had been to illustrate to readers away from the scene, particular those overseas in countries that rarely get earthquakes, that earthquakes are not events that happen and then ”that’s it”. Instead, there is a long sequence of aftershocks.

    I was up in Christchurch over the holiday break, arriving after the initial sequence. Initially aftershocks are very frequent, with the earth reminding me of a jelly that is settling from having being moved – one whose actions are stretched over the much slower geological timescale.

    For this particular aftershock series, I’ve found that I generally aftershocks of magnitude less that 4 don’t wake me. (Bear in mind I was sleeping a good ~25 kilometres away.) A consequence of them is repeatedly awakening during the night. As you might imagine that tires people and adds to any psychological stress.

    Anyway, enough rambling thoughts.

    At 10:48pm tonight there was a magnitude 4.3, 10km to the east of Christchurch (i.e. just off the South New Brighton coast) at an estimated depth of 10km.

    I haven’t recorded the earlier magnitude 4+ aftershocks.

  • Maybe I should shift the criteria slightly, raising the threshold a little? Anyway:

    Friday 4:45am Dec 30th (I did say something about awakening from sleep before…): Magnitude 4.4, just off New Brighton coast (~15km from city centre), depth ~15km.

  • Saturday 1:44pm, magnitude 4.8, approx. same location and depth as the one-before-last: ~10 east of city centre just off Sth. Brighton coast, depth ~10km. Initial report at USGS is magnitude 5.3.

  • Monday January 2nd, 2012.

    Last night was a bumpy old time for Christchurch, including a magnitude 5.1 followed later by a magnitude 5.5. Noting only those of magnitude 4.0 and greater, GeoNet is reporting a sequence of:

    10:05pm: 4.0 (depth 7km)

    1:27am: 5.1 (depth 15km)

    1:31am: 4.3 (depth 12km)

    5:45am: 5.5 (depth 15km)

    5:50am: 4.2 (depth 12km)

    5:54am: 4.1 (depth 12km)

    6:06am: 4.1 (depth 12km)

  • 9:01am sees another magnitude 4.1 (depth 12km).

    Should add that these, like all the recent aftershocks, are all immediately to the east of the city – i.e. just off the coast.

    No reports of damage; lots of grumps about lack of sleep, including one sarcastic wit reframing the aftershocks in a mock weather report and another reporting that their rooster woke early. (Hmm.) Japan has also experienced a sizeable aftershock (magnitude 6.8).

  • Thursday 5th Jan., 8:28am: 4.8, same area and depth.

    This photostream has a mix of the good and some coverage of the central city from behind the barricades on the central city walk:

    No serious damage (as is typical for the latest after shocks). Those writing on twitter express general annoyance and there are a number of complaints about Christchurch City Council chief executive Tony Marryatt’s 14+% pay rise* but there’s also this more poetic take:

    @CherylBernstein That one had the power lines bouncing up and down. Then the silence. Then the birds start singing again.

    (* The rise itself is more than most take home.)

  • Tuesday, 10th Jan. 2012.

    As I mentioned in an earlier comment one of my original motivations behind reporting each somewhat larger aftershock was to convey that major earthquakes are not ‘one bang’ events – aftershocks go on for quite a while.

    I’m going to now only report those that are magnitude 4.5 or greater. This latest series of aftershocks are a little deeper and are just off-shore (i.e. not immediately under the city) – with that in mind raising the threshold a little (in a completely arbitrary way!) seems sensible. I may raise the threshold further later.

    I’ve been away over the past few days. During that time there has been (all located 10-20km east of city centre just of New Brighton coast):

    Jan 6th, 2:20pm. Magnitude 5.0, depth ~5km.

    Jan 6th, 5:10pm. Magnitude 5.1, depth ~33km.

    Jan 6th, 8:04pm. Magnitude 4.7, depth ~11km.

    Jan 7th, 1:21am. Magnitude 5.2, depth ~15km.

    Jan 7th, 2:02pm. Magnitude 4.5, depth ~8km.

    There is also news of a short memorial service on February 22nd to note this anniversary. (The first earthquake was on Sept. 4th 2010 but no lives were lost.)

  • Jan 15th, 2:47am. Magnitude 5.0, depth ~9km.

    Lots of chatter in the wee hours on twitter; no reports of damage. First time that I have seen no report at all on the stuff and nzherald websites for a magnitude 5+. Seeing general comments that now the CBD has an excess of car parking through reuse of the land where buildings have been demolished, whereas it previously had a shortage.

    There’s a long article on the issue of heritage buildings in the NZ Herald:

  • Monday Jan 23rd, 6:46 am. Magnitude 4.5, depth ~12km.; ~ same area. General muttering on twitter about early starts (along with comments about Marryatt’s pay rise), but not many people tweeting.

  • This article discusses increases in costs of insurance in the wake of the earthquakes. The cite and average rise of ~30%. My own insurance costs rose 50% last year – I’m not in Christchurch but Dunedin, one of the lower risk parts of the country for earthquakes. There’s more than Christchurch affected by this.

  • Updating this late, as for some reason I wasn’t informed through the usual feeds:

    Friday, January 27, 8:42 pm. Magnitude 4.6, depth ~11km. Location: to west of Rolleston.

    Unlike most of the ones reported over the part few weeks, which were offshore to the east of the city, this is to the west, nearer to the location of the original magnitude 7+ of Sept. 4th 2010. A lot of people on twitter reported prolonged shaking, along with some ridiculous jokes as usual. (e.g. “Did Gerry Brownlee fall over?” (bad taste, but he’s a politician and it comes with the territory, I guess) or “Reading the twitter stream after a #eqnz is getting to be a bit like a wine tasting. “bit of a shake followed by a wobble.”” @RogoNic)

  • The link below points to an eloquently written protest (for want of a better word) by Dr Ann Brower, a senior lecturer of public policy at Lincoln University, who testified this month at the Royal Commission of Inquiry into Building Failures in the Christchurch Earthquake. The wall of a building known to be at serious risk of collapse fell on 13 bus passengers & nearby pedestrians. Of these she was the sole survivor –

  • The first aftershock of magnitude 4.5 or greater in over a month occurred early this afternoon, Tuesday May 15th 1:27pm: magnitude 4.5, depth 11km, just off the New Brighton coast (about 10km NE of the city centre), followed a few minutes later by a magnitude 3.5. Accompanied by the “usual” chatter on twitter (via #eqnz ). Among other things the aftershock, apparently, gave some builders up on scaffolding a bit of a hurry-up.

  • Sunday May 20 2012 at 5:06: magnitude 4.8, depth 8 km, of the coast of the estuary/Sumner region (a little south of the previous aftershock reported above).

  • Friday 25th May, 2012, at 2:24pm there was a magnitude 5.2 event off the Brighton/New Brighton coast (10 km east of the city centre), depth estimated at ~11km.

    This story on Stuff reports that the city centre was temporarily closed down, but there were not reports of (significant) damage or injuries.

  • Aftershock this afternoon, September 21st: magnitude-4.3 quake at 1.35pm, 15 kilometres east of Christchurch, depth ~12km.

  • October 10th, 11:51 am: magnitude !4.1, depth 13km, again 15 kilometres east of Christchurch. (Can’t give more location details as GeoNet server is not responding

    A couple of tweets:

    This from Anna Turner, ‏@AnnaTurner22: Was in the dairy and the owner yelled and dived under the counter- slightly off-putting

    And this from Kathy Lowry, ‏@binkle: Haven’t felt one quite that wibbly for ages. Heart pounding. Poo!

  • Yes, they’re still getting them.

    Last night, at 3:17am, saw a magnitude 4.1 ~20 km east of the city centre, depth ~8km. (Off the coast to the east of the city.)

    Usual noise on twitter. This time featuring complaints about disrupted sleep, as you might expect!

  • Sat Jan 19 2013 9:15 PM (NZDT): Quake 20 km west of Christchurch, intensity strong, approx. M4.6, depth 10 km

    More details at:

    Civil Defence advises that there have been no reports of damage. Felt widely in North Canterbury (from eye-balling tweets on #eqnz).

    A sample of the tweets (unattributed, sorry – out of time):

    “Well that rattled my crockery”

    “These things have turned me into an adrenaline junkie.”

    “That one had my daughter running into our room in Timaru…”

    “felt like my desk chair had a pneumatic malfunction”

    “That aftershock was like going over a cattle stop at high speed.. Yes, I was driving”

    “That was a punch from below; felt the floor rise to meet me.”

    “Dammit, first breakage since Feb 2011”

    “11000 and still going strong, With form like that Wonder if #eqnz is eligible for the BlackCaps??”

  • Keeping up the reports/record of earthquakes of magnitude ≥ 4 …

    Wed Jan 30 2013 3:43 PM (NZDT): 35 km west of Akaroa, magnitude approx. 4.2, depth 19 km. Further details at geonet:

    #eqnz fairly ho-hum about it.

  • Mon Feb 4 2013 4:44 PM (NZDT): 10 km east of Christchurch, intensity strong, approx. M4.1, depth 5 km

    (Apparently later down-graded to magnitude 3.6. Twitter crowd on
    #eqnz not to agreeable to that! Way too much spam in #eqnz.)

    “AdrienneRewi: OK… let’s have a sweepstake to see whose Twitter #eqnz comment will be quoted in The Press/Stuff”

  • Sun 19 May, 2013:

    Geonet reports a magnitude ~4.0, strongly felt, on Friday 3:59pm, ~6km depth, 25 km west of the city (immed. south of Rolleston). Followed by a series of ≥ M3 events.

    This image has a map of all the events in the Christchurch area to date shown by depth (colour) and magnitude (radius of circle). (US Navy data it seems.)

    CERA reports increasingly removing the cordoned-off areas of the central city.