A newby question..

[Alkemac]

If the earths axis moved by 25cm because of the quake in Japan, what (how much) effect will this have on variation, and GPS accuracy ?

http://www.dailymail.co.uk/sciencetech/ ... -25cm.html

[Stephan van Tonder]

probably 25 cm?

[V]

Interesting question! My first thought would be that the direct effect will be none, because the Earth's axis, the magnetic and geographic poles are all different and only the axis has moved. All these, including the continents are in constant, albeit gradual, motion anyways and deal with this, maps and the GPS systems are working on a mathematical model that is fixed to a specific date. There are lots of map datums, but the most commonly used is WGS84. That's ways over 20 years old. The changes due to the quake, if any, will be well within the error margins of the current maps and positioning systems.

Secondary effects, absolutely no idea.

I guess, the changed coast line will give some work for the Japanese mappers for some time to come, though. However, dealing with their cracked and leaky nuclear power plants might be a little higher on the priority list.

Cheers,

V.

[Alkemac]

Thanks V..

Stephan, I gathered that much - it's the secondary effect that is not always so obvious.