Latest
This post is no longer updated due to other updated information located on this site
Please refer to:
Christchurch Shakes - for a running summary of seismic developments
Christchurch -why warnings have been given - for commentary on the long term viability of Canterbury-Christchurch regarding potential future seismic hazards
Original post begins
Data sourced from the University of Canterbury's online quakemap covering the time frame March 14-April 11 2011
The red box shows the highest mag aftershock for the day in the source area.NOTES:
- this data may include events in the South Island beyond Christchurch & Canterbury, but significant ones are noted -eg March 23 the 3.9 event marked A occurred at the Alpine fault, west of the Canterbury region
- the highest magnitude event in Christchurch occurred on March 20 ( the dreaded Supermoon day)
- on April 11, a M5.1 occurred in the sea, east off the lower North Island. This is the highest mag seismic event since March 20
- from March 16 the daily totals of events are given along the bottom border
- a general downward trend is expected by seismologists, in frequency and magnitude: though Geonet acknowledges
this has been a particularly rich sequence compared with the forecasts
As a matter of interest, considering there are so many very bright minds trying to unpick the mystery of where and when quakes occur, some options you can observe:
1. The moon's maximum north (N) or maximum south (S) declination is regarded as influential on seismic activity. A few dates coming up are:
April 8 (N), April 21 (S); May 6 (N), May 18 (S); June 2 (N), June 15 (S), June 29 (N); July 12 (S), July 27 (N)
The window of influence according to Richard Nolle is 30hrs either side of the target date
2. A formula called tidal force - which combines a range of lunar factors, all of which are cyclic and therefore can merge in influence by several factors occurring within a reduced time-frame: a synergistic sun-moon effect is produced affecting the water and the crustal surface of the earth
For April the dates (column 4) from 13th to 21st are when the sun and moon together are said to exert their strongest combined force as shown by % in far right column.
This is not just a standard calculation related to New and Full Moons which are generally believed to be the strongest times of influence. In April, New Moon is 4th and Full Moon 18th
In April 2011 the full moon on the 18th coincides with a 94% tidal force, but the moon's position in latitude/declination is only a few degrees south of the equator (max south 21st) but it will be closest proximity to earth (perigee) 17th-18th. I'd expect some increase in extreme weather/seismicity affecting areas that are usually active, but not a mega-event. May and June look more powerful.
Both theories have success as quake predictors but both are imperfect in failing to get consistent results;
the Moon was near max North on March 11 - exact on March 12 -re the Japan quake
the Moon was 3 days off max South ( Feb 22 Christchurch quake vs Feb 25 max)
the Boxing Day tsunami 2004 was Moon at max North and Full Moon -but Moon was at far apogee -so the tidal % was only 11. Clearly max. declination with full moon alignment were determining factors.
the Chile quake of Feb 27 2010 had the moon being beyond max north date (23rd) but it was right on lunar perigee and 1 day before full moon. The tidal percentage was 95. So here the tidal sun-moon effect seems to have ruled.
And more could be said concerning eclipses...next time.
Update April 15
NASA Science News site item suggests 2011 is seeing more solar activity directed towards earth - the solar wind comprising electrically charged plasma interacts with the magnetic field that surrounds earth ( essentially we live on a magnet!) The interesting point here is that on March 7 the sun send a big force towards earth, taking a few days to arrive here. It's arrival on March 10 was identified by the auroral lights and their spread - down to latitude 45N in some American states.
And what happened on March 11 2011 in Japan? Some researchers are convinced that space-weather like this plays a significant role in earthquake activity.
Update April 16 a.m.
Noting an uptick in quake activity (21) events in the South Island on Friday 15th after a lull period as well as other activity in the North Island. Seeing as there are ebbs and flows in the nature of tidal behaviour the temptation is definitely there to find a link between quake activity and lunar/solar-lunar/other planetary cycles.
On Friday 15 the tidal force % was 97% -highest for the month, also 2 days before exact perigee and 3 days before full moon, then moon will be maximum south on 21st. A turbulent period would be expected in this time frame April 14-22.
What's happening globally? The M5+ records show more diverse action has been building, compared to Japan's recent near total domination of the stats. Note Tonga is quite active = closer to home. Nevada at latitude 38N, since April 10, has repeated small events like currently seen in Christchurch.
Globally the latitude bands 30-40 degrees north or south of the equator appear to be dominant as detected in a prior analysis posted by Waiheke News on worst earthquake zones
p.m. The largest aftershock since Feb 22 occurred in Christchurch at 5.49 pm, in the seafloor, Diamond Harbour, M5.3 ( prior highest was March 20)
Currently 2 days from Full Moon; tidal force is very high 96%; one day before the moon's perigee position and the moon is on the other sensitive latitude/declination in space = on the equator.
P.S. you won't hear Ken Ring go to the media this time but he did warn of this period: will post if the link can be located. Found it - a global chart indicating M5+ activity today around the world - here
Update Monday April 18
"We are locating events under Darfield, under Lyttelton, and all the way out to the coast. It is still a very active area."
The shocks are gradually becoming smaller and further apart, but would not stop completely until around February 2013.
...the probability of an earthquake of magnitude 6 or greater within the next year was roughly 6 per cent NZ Herald report April 18
Please read prior and upcoming posts on this topic to ensure you are factoring in the reality of the situation in Christchurch.
Update April 24
A M4.3 in Lincoln, Chch at 8.51pm
Update May 10
If the highest quake of the day occurred outside of Canterbury, it is indicated as Seafloor, Alpine or Marlborough. On April 30 it is shown that a 3.9 occurred in Chch, but a 5.2 occurred in the Alpine region.
This data shows the trend, with number of quakes per day along the bottom border, showing a lowering of totals and a bunching of smaller mag quakes, down to a max of M3 on May 3.
An uptick may be observed from May 5, when the energy built. The next event, which occurs the day after the 9th, ie May 10th a M5.3 in Rolleston, shows a sudden surge of energy, but this location, Rolleston saw the M4 max on May 9. So whilst the general trend is down, the recurrence of shallow events over M5 must be of concern to residents. (GNS forecast data)
Mouse-over this quake data graph as well for more info.
Update May 16
Today's events included an unusual sequence of 3 events M4.0-4.6, 2 in the seafloor, 1 south of Springston
Dec 16 2011:
The downtrend evident in the Quakelive graph [-just prior to a fourth sequence occurred]
 |
| Quakelive data - click to enlarge |
On Dec 23 2011 a fourth quake sequence began, due to a M5.8 in Pegasus Bay. Details and ongoing commentary re this location are found in this specific post
