Monday, April 19, 2010

Has the Earth moved for you?

No, I'm not doing a survey that assesses how many people share Lily Allen's sentiment in "Not Fair".

It just seems that there is a lot more seismic activity these days. In just the last week we've had an earthquake in China and the ongoing volcanic activity at Eyjafjallajokull. (For those struggling to pronounce that take a hint and shorten it to "the Eyja-fjalla glacier" - and the first bit is easier if you realise it is island falls.)

This follows on from Haiti and a slew of other earthquakes.

Now, it is entirely possible that there isn't a real increase in seismic activity, just an increase in the reporting of it. The reporting can increase both because of the extent now of seismic probes - every tremor is well documented - and the prevelance of communications and media technologies which makes reporting the event and dramatic pictures more readily achievable. The US geological survey supports the view that there is no increase in numbers just an increase in the ability to locate them. (at time of writing their page was last modified Page Last Modified: October 27, 2009 14:01:59 UTC aand said;

Although it may seem that we are having more earthquakes, earthquakes of magnitude 7.0 or greater have remained fairly constant.

A partial explanation may lie in the fact that in the last twenty years, we have definitely had an increase in the number of earthquakes we have been able to locate each year. This is because of the tremendous increase in the number of seismograph stations in the world and the many improvements in global communications. In 1931, there were about 350 stations operating in the world; today, there are more than 8,000 stations and the data now comes in rapidly from these stations by electronic mail, internet and satellite. This increase in the number of stations and the more timely receipt of data has allowed us and other seismological centers to locate earthquakes more rapidly and to locate many small earthquakes which were undetected in earlier years. The NEIC now locates about 20,000 earthquakes each year or approximately 50 per day. Also, because of the improvements in communications and the increased interest in the environment and natural disasters, the public now learns about more earthquakes.

According to long-term records (since about 1900), we expect about 17 major earthquakes (7.0 - 7.9) and one great earthquake (8.0 or above) in any given year.

They even record a list of them.

Another expert claims an increase in seismic activity could occur through global warming as even few degrees increase in rock temperature softens the joints between geological plates. When the sea level rises, pressure of the water may also release energy between plates in tension. We are coming out of an ice age so this will happen anyway, global warming is just accelerating the process.

This asame person notes there is an "apparent" increase in the number of recorded earthquakes but that is due to the increase in the amount of research stations. Further, earthquakes and tsunamis will seem to get worse as the world population explodes, more people getting effected by seismic activity than before, and media or television coverage becomes more dramatic.

So it seems like the conspiracy theory about the large hadron collider is wrong.

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