Not even 24 hours have passed since the deadly 8.9 Mw earthquake in Honshu, Japan, and already conspiranoics, cranks and even some broadcasters are opening the door of the panic room in the internet: Are we having more earthquakes now than some years ago? Is the end of the world approaching? Is Gaia trying to get rid of us?
The answer to all these questions is a big NO.
As most of people know, an earthquake is the sudden slip on a fault, and the consequent instantaneous emision of energy in the shape of seismic waves that was previously accumulated in a fault. There are many reasons for that, and many different types of faults in many different parts of the world, but the Ring of Fire in the Pacific is certainly one of th most hazardous areas in our planet in terms of seismicity.
The USGS, even though is the national geological survey for the USA, registers earthquakes in all the planet and publishes statistics about them. So, are earthquakes from frequent lately? The answer is in the facts, as usual in this topics.
Take a look to these graphs, where the number of earthquakes, classified by number and per year, is depicted. It is clear and obvious that the frequence of quakes of magnitud over 7.0 stays pretty constant:
But, we may think: "Every year it seems that more people die because of natural catastrophes". Well, it may seem like that until we take a look to the statistics, and then this idea simply vanishes.
What happens is a mixture of not so natural phenomena.
In first place, we have instant communications around the whole of the planet. And this didn't existed before. We switch on the TV when we get up, and we see in the news in UK or USA or Finland what is happening at the moment in Japan, tens of thousands of kilometres away.
Secondly, the network of seismograph stations is more complete every year, and therefore the amount of earthquakes located is higher (and also the amount of smaller earthquakes detected. In 1931 there were 350 seismograph stations in the world. Today, there are more than 8000. Of course, that information is easily available and fills the media constantly. It is far more easy now to report an earthquake of 5.0 or 6.0 Mw, than it was in 1985.
In the last years, big quakes have occurred in populated areas, being more relevant. Sumatra, Haiti, Chile, Japan... But do we care when an earthquake happens in the Aleutians? Hazard is not synonym of risk! Risk involves exposure of human lives, of economically valuable places.
And of course, the Mayans didn't predict anything
(Fonte : Structuralgeology.org )
The answer to all these questions is a big NO.
As most of people know, an earthquake is the sudden slip on a fault, and the consequent instantaneous emision of energy in the shape of seismic waves that was previously accumulated in a fault. There are many reasons for that, and many different types of faults in many different parts of the world, but the Ring of Fire in the Pacific is certainly one of th most hazardous areas in our planet in terms of seismicity.
The USGS, even though is the national geological survey for the USA, registers earthquakes in all the planet and publishes statistics about them. So, are earthquakes from frequent lately? The answer is in the facts, as usual in this topics.
Take a look to these graphs, where the number of earthquakes, classified by number and per year, is depicted. It is clear and obvious that the frequence of quakes of magnitud over 7.0 stays pretty constant:
But, we may think: "Every year it seems that more people die because of natural catastrophes". Well, it may seem like that until we take a look to the statistics, and then this idea simply vanishes.
What happens is a mixture of not so natural phenomena.
In first place, we have instant communications around the whole of the planet. And this didn't existed before. We switch on the TV when we get up, and we see in the news in UK or USA or Finland what is happening at the moment in Japan, tens of thousands of kilometres away.
Secondly, the network of seismograph stations is more complete every year, and therefore the amount of earthquakes located is higher (and also the amount of smaller earthquakes detected. In 1931 there were 350 seismograph stations in the world. Today, there are more than 8000. Of course, that information is easily available and fills the media constantly. It is far more easy now to report an earthquake of 5.0 or 6.0 Mw, than it was in 1985.
In the last years, big quakes have occurred in populated areas, being more relevant. Sumatra, Haiti, Chile, Japan... But do we care when an earthquake happens in the Aleutians? Hazard is not synonym of risk! Risk involves exposure of human lives, of economically valuable places.
And of course, the Mayans didn't predict anything
(Fonte : Structuralgeology.org )
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