More earthquakes?

8 May 2010

Hello everybody,

Let’s rock! 🙂

Are there now more earthquakes than normal ?

Earthquake activity in the last 8 to 30 days
Here is a bit of info about the No Trend in Earth’s Earthquakes:
1) A nice colour graph with all the raw data from the US Geological Survey (USGS):
Earthquakes Located by the NEIC 1990 to present

2) Are Earthquakes Really on the Increase?

We continue to be asked by many people throughout the world if earthquakes are on the increase. 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.
Are earthquakes getting worse? No
” …  it turns out that large earthquake frequency has not changed at all over the last 20 years”
Ian Saginor, Ph.D., is a volcanologist and professor of geology at Keystone College.
His research is on the evolution of volcanoes in Central America.
“The bottom line is that Weisman’s claims that earthquake frequency is increasing and that earthquakes in Haiti and Chile are caused by global warming are unsupported by the scientific articles he uses to form his conclusions. The effect of his article is to take several well-meaning, preliminary, cautious and limited scientific studies and create unnecessary fear and confusion in the general public”
” Most scientific papers do not lend themselves to sound bites or headlines. That means the media needs to do a much better job understanding them. For their part, scientists need to be willing to confront these errors before they spread. Whatever effect climate change has on our planet in the future, inaccurate reporting of research leaves the public at a huge disadvantage and cannot be tolerated.

Scientists say seismic surge is only a media theme
“It might appear quakes are happening more frequently, but media attention, rather than a surge in seismic activity, could be the reason. Richard Luckett, a seismologist with the British Geological Survey, said earthquakes as large as the one that struck Qinghai happen somewhere in the world every few weeks. “This is definitely not a spike,” Luckett says. Attention has instead been drawn to quakes recently by their “unusual severity and unfortunate geography”.”
4) And a few more of the same opinion:
And something with a bit more vocal disagreement 🙂
Sov Gott! 🙂

PS But the world of Geology still has magnificent surprises for us:

Mexico’s Cave of Crystals stunned geologists when it was first discovered in 2000. The underground chamber contains some of the largest natural crystals ever found – some of the selenite structures have grown to more than 10m long.
Iain Stewart in the cave of crystals

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