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Another big quake in the next month? GeoNet's three scenarios for lower North Island

GeoNet and Geoscience released new projections this morning showing a quake over a 6.0 magnitude is only 10% likely during the next month near Eketahuna.

Researchers released three scenarios with less frequent aftershocks being the most likely scenario over the next 30 days.   

The chances of a big one hitting have decreased since a magnitude 6.2 quake struck 15 kilometres east of Eketahuna on Monday afternoon.

GeoNet received more than 9000 reports from the public who felt the damage, which rattled through a seismically active area of the country that extends from Wellington to the Gisborne region. Reports of damage include a Hobbit movie eagle sculpture which fell from the Wellington airport’s ceiling.

Since Monday the area has registered more than 850 aftershocks, most of which are below 3.0 magnitude.

Researchers say there is a 9% chance of a 6.0 to 7.0 magnitude quake in the next 30 days and less than a 1% chance of big quake over 7.0 in magnitude.  

GeoNet calls the area “geologically complex” where the Pacific tectonic plate is being forced sideways and downward into the mantle below the Australian plate at a rate of about 42 millimetres per year.

Since 1940, there have been 31 earthquakes of similar magnitude in the area. Only two of these have been followed by quakes of a similar or greater size.

In June 1942 a magnitude 6.5 earthquake near Masterton was followed by a magnitude 6.8 in August and a magnitude 6.0 in December that year. 

In February 1990 a magnitude 5.9 earthquake near Weber and Porangahau was followed by a magnitude 6.2 earthquake in May 1990 in the same area, which damaged buildings near Weber.

Comments and questions
4

Geonet scientists and weather forecasters - two groups that should stick to what has happened rather than what is going to happen as neither has much sucess in forecasting stakes!

Geonet are typical state scientists - lots of detail and percentages, but no real information that anyone can use to prepare themselves.

Ken Ring on the other hand, tells people to be aware of strange weather patterns, animals misbehaving and masses of beached whales. He also has an in depth understanding of the phases of the planets and particular the moon and the stresses it places on the earth's crust. It's not rocket science, as every keen fisherman knows the tides are influenced by the moon and tidal charts exist for that reason. The Maoris were also using the same patterns for centuries to predict storms and bad weather in advance.

Ken Ring warned that the period between 16 -23 of Feb 2011 was a high risk period. Early on the morning of Feb 22 we had a purple sky, and 101 beached whales on Stewart Island the day before. We also had a buildup of small shocks at 3am in one area, rather than spread over a wider area.

The two days before this recent earthquake, we had a buildup of repetitive small shocks around the middle of NZ. We had a major pod of whales that beached, released and re-beached. We also had the strong weather from coming down from the north west . I predicted the North Island or Wellington / Marlborough are likely to get a big shock. If I can guess, why can't Geonet with their quasi-million dollar funding?

The Japanese and others have built equipment that monitors changes in the atmospheric electrical balance that are a pre-cursor to an earthquake, as pressure builds up on the ground, sometimes days in advance. The pressure builds up and the piezo electric effect creates an electric charge, which is also responsible for the sky colour changes and the strange lighting effects we see when the earthquakes happen at night.

Instead of spending money running numbers on probabilities, they should invest in real technology and have it ported to their website so that the public can be informed and make their own decisions.

The 9% chance they have given of a 6.0 or a 7.0 is based on previous shock patterns. As we know with both the Chch quakes and this latest one, that earthquakes do not conform to a pattern. They were unexpected as there were no previous major fault lines.

Earthquakes are not performing elephants, they can't be controlled or act to a pattern. Statistics after the event are meaningless. Focus should be on early warning, not statistics.

Ken Ring? Seriously? Not forecast? Seriously? You both need to study some geology.

I appreciate your sincerity Gary, but the predominant forces on the earth's crust are gravitational. Both from internal gravity and external gravity from the moon and other planets. The internal forces of gravity and it's associated magnetic tides setup internal forces.

The gravitational force between the earth and the moon from the moon is 1.985 x 10 to the power of 20 newtons. Which converts to 20242386543865980 tonnes. Probably explains why oceans rise and fall (tides) twice a day, by up to a metre or two. A lot of water don't you think huh?? Looking solely to geology for the cause is short sighted, The geology tells us what has happened, but only partly explains the cause.

Ignoring the force of 20242386543865980 tonnes is like two ants studying a golf ball and theorizing it's cause of movement while being completely ignorant of the existence of the golfer who is the real cause of its movement.