Unprecedented Earthquakes: Understanding the Recent Surge in Seismic Activity

[The_Absolute]

First Haiti, then Chile, and now http://news.yahoo.com/s/ap/as_taiwan_earthquake" what the hell is going on here? Why are there so many earthquakes, happening so fast? Is there a scientific, geological explanation for why there are so many earthquakes, more than we would usually see? Are the tectonic plates shifting?

There could be another reason for this, but I can't discuss those matters on this forum without being warned or banned by the moderators. Which I am now on the verge of being banned.

 

[DaveC426913]

The same reason train wrecks and other disasters come in waves: preferential news reporting.

You'll note that the Taiwan quake was kid stuff. No deaths. This happens a zillion times day around the world and never makes the news. Until it's news.



Strange article. Contradictory.

This [6.4] is the biggest quake to hit this region in more than a century...

[said Kuo Kai-wen, director, Central Weather Bureau's Seismology Center].
Then later in the article:

However, a 7.6-magnitude temblor in central Taiwan in 1999 killed more than 2,300 people.

 

[Aquafire]

First Haiti, then Chile, and now http://news.yahoo.com/s/ap/as_taiwan_earthquake" what the hell is going on here? Why are there so many earthquakes, happening so fast?

It's just your impression.

Fact is, the rate has remained relatively steady.

What HAS INCREASED is the number of ground stations beingable to record these seismic events.

Information is available to read here.

Are Earthquakes Really on the Increase ?

http://earthquake.usgs.gov/learn/topics/increase_in_earthquakes.php"

And here for more general stats.

http://earthquake.usgs.gov/earthquakes/eqarchives/year/eqstats.php"

 

[DaveC426913]

 [PLAIN]http://earthquake.usgs.gov/learn/topics/increase_in_earthquakes.php

[/PLAIN]

More data is available here.

[PLAIN]http://earthquake.usgs.gov/earthquakes/eqarchives/year/eqstats.php

[/PLAIN]

Er, you want to be lookin' for this icon: https://www.physicsforums.com/Nexus/editor/createlink.png ,[/URL] not this one: https://www.physicsforums.com/Nexus/editor/code.png

 

[Aquafire]

Dave thankyou.

My coding skills are not what they used to be.

Apologies to Mods. I will correct those posts.

Cheers

 

[ThomasEdison]

First Haiti, then Chile, and now http://news.yahoo.com/s/ap/as_taiwan_earthquake" what the hell is going on here? Why are there so many earthquakes, happening so fast? Is there a scientific, geological explanation for why there are so many earthquakes, more than we would usually see? Are the tectonic plates shifting?

There could be another reason for this, but I can't discuss those matters on this forum without being warned or banned by the moderators. Which I am now on the verge of being banned.

The Richter Scale Wiki.
http://en.wikipedia.org/wiki/Richter_magnitude_scale

I wish I could highlight the chart of frequency of quakes but I don't know how.


Anyhow scroll down a bit and check out the frequency chart on the wiki. An average year for Earthquakes means many large quakes.

 

[billiards]

The distribution of earthquakes is thought to obey fractal statistics. This means that over the long term the distribution of earthquakes is quite well behaved, in accordance with the basic law that you have lots of small earthquakes and few large earthquakes over a long period of time. However the law says nothing about when these earthquakes WILL occur, if for example you expected a magnitude 9.0 earthquake once every 30 years, and then you got two in a week that wouldn't necessarily violate the law, because you might not have another one for 60 years so over the long term the distribution holds. Besides, the Haiti earthquake was not especially strong, it was devastating because of its location but from a geological perspective it was one of those earthquakes that we expect to occur quite frequently, same goes with the Taiwanese earthquake except this one looks to have been less devastating (fortunately); the Chile earthquake was very strong. Incidentally, the largest earthquake you can possibly get is about is about a magnitude 9.2 (measured in degree of shaking), increasing the energy input will simply go into tearing up the rocks near the hypercenter and won't propagate as seismic waves.

 

[Count Iblis]

There could be another reason for this, but I can't discuss those matters on this forum without being warned or banned by the moderators. Which I am now on the verge of being banned.

Yes, if you write something like this:

From deep within the Earth's interior, a huge http://en.wikipedia.org/wiki/Mantle_plume" .

You could be admonished by the moderators.

 

[The_Absolute]

Why were there so many more casualties in the Haitian quake than in the Chilean quake?

 

[DaveC426913]

Why were there so many more casualties in the Haitian quake than in the Chilean quake?

Surely, you know answers to this.
eg.
- location of epicenter relative to populated areas
- widespread poverty leading to substandard (or nonexistent) building codes
- etc.

 

[Count Iblis]

http://www.scientificamerican.com/article.cfm?id=massive-himalayan-earthqu"

Bilham and Molnar suggest that up to seven earthquakes in the 8.1 to 8.3 magnitude range are overdue in this region. Considering past human tolls from earthquakes and the population increases that have occurred since then, the authors estimate that 200,000 people could perish in a single quake. If a massive earthquake strikes near one of the heavily populated cities in the Ganges Plain, however, "such an estimate may be too low by an order of magnitude."

 

[malm1987]

The Absolute and SamTHorn: What exactly are you implying might be the cause of this? Please don't say that it's something like a rogue planet?

Anyhow, I thought about this specific topic (increases in earthquakes) and thought I would ask you if anyone knows why there seems to be quite an uptick in m2-m4 earthquakes since the beginning of 2000 til now?(http://earthquake.usgs.gov/earthquakes/eqarchives/year/eqstats.php )

And I know, the last two years show a drastic decrease, but only due to the fact that no m4,5 or less was registrered outside the US.

 

[Astronuc]

It does appear that the number/frequency of earthquakes is increasing, or the detection is just better, or a combination.

http://earthquake.usgs.gov/learn/topics/increase_in_earthquakes.php

http://earthquake.usgs.gov/earthquakes/eqarchives/year/info_1990s.php

I suspect it goes in waves like the climate does.

 

[Kerrie]

It does appear that the number/frequency of earthquakes is increasing, or the detection is just better, or a combination.

http://earthquake.usgs.gov/learn/topics/increase_in_earthquakes.php

http://earthquake.usgs.gov/earthquakes/eqarchives/year/info_1990s.php

I suspect it goes in waves like the climate does.

I would have to lean towards detection, plus the combination of information traveling quickly among a more populated planet. Our ability to detect earthquakes spans in such a tiny fraction of the time that earthquakes have been happening.

 

[goodscoolls]

" elastic strain energy is released and elastic waves are radiated, leading to an earthquake. Induced earthquakes may happen for a variety of reasons, including extraction of minerals from Earth and the collapse of large buildings... " so don't be so afraid of the natural phenomenon. it happens according to its own rules and it exists. so your worrying won't help!

 

[Chrisphysics%]

There is an increase in stronger earthquakes globally (M>5.0), this information is available to the public, see USGS page ( http://earthquake.usgs.gov/earthquakes/eqarchives/year/eqstats.php" ).

Why are there more stronger earthquakes? Some have hypothesized that the increase may be caused by the melting of glaciers globally. The theory states that melting glaciers will reduce the load on the Earth's crust, increasing tetonic plate movement. Melted water from the glaciers flows into the ocean and increases the load in another location. It would be this change in loading that could increase tetonic motion and increase earthquake activity. This theory was put forward by a joint NASA-USGS study http://www.nasa.gov/centers/goddard/news/topstory/2004/0715glacierquakes.html" .

It is important to note that the NASA-USGS study also shows that the melting of glaciers may increase earthquake frequency in areas that are otherwise inactive.

 

[DaveC426913]

There is an increase in stronger earthquakes globally (M>5.0), this information is available to the public, see USGS page ( http://earthquake.usgs.gov/earthquakes/eqarchives/year/eqstats.php" ).

Can you direct me to where, on that page, it actually says there is an increase and that the increase is statistically significant?

Because if not, the rest of your post is dead in its tracks.

 

[Chrisphysics%]

Earthquake statistics for 2000, 2010 and 2011 (projections) are as follows for M*>5.0:

2000: 1505
2010: 2117
2011 (projections): 3571.

Therefore, when compared with the year 2000, there were 41% more earthquakes (M*>5.0) in 2010 and the projections yield a 137% increase for 2011, when compared with 2000. After the M9.0 in Japan there has been an increase in stronger earthquakes. Some experts say that the total number of earthquakes has not changed globally, however, these results show an increase in stronger earthquakes (M*>5.0).

Finally, it is also important to emphasize other scientific facts that support this. In the past, increasing atmospheric temperatures and melting glaciers lead to an increase in earthquake activity, see NASA-USGS article.

 

[russ_watters]

Looking at how widely the frequencies of the other magnitudes change, it doesn't look at all unusual to me to see large swings from one year to the next. Do you have an actual statistical analysis or are those numbers it?

...and have you read the parts of your own link that debunk your claims? From the link:

The USGS estimates that several million earthquakes occur in the world each year. Many go undetected because they hit remote areas or have very small magnitudes. The NEIC now locates about 50 earthquakes each day, or about 20,000 a year.

As more and more seismographs are installed in the world, more earthquakes can be and have been located. However, the number of large earthquakes (magnitude 6.0 and greater) has stayed relatively constant. See: Are Earthquakes Really on the Increase?

and:

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.

When your own source directly contradicts your assertion, it's going to be tough to get any traction on your claims...

 

[D H]

Earthquake statistics for 2000, 2010 and 2011 (projections) are as follows for M*>5.0:

2000: 1505
2010: 2117
2011 (projections): 3571.

This is bordering on misinformation.

First off, where did you get that projection?

Secondly, and more importantly, you are looking at small (less than magnitude 6.0) earthquakes here. Our ability to detect and locate those small earthquakes is on the increase. That does not mean that the number of earthquakes is on the increase. Our ability to detect and locate large earthquakes hasn't improved all that much for the simple reason that we had the ability to detect and locate almost all such events a long time ago.

From this page, http://earthquake.usgs.gov/earthquakes/eqarchives/year/eqstats.php ,

As more and more seismographs are installed in the world, more earthquakes can be and have been located. However, the number of large earthquakes (magnitude 6.0 and greater) has stayed relatively constant.​

From http://earthquake.usgs.gov/learn/topics/increase_in_earthquakes.php ,

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.​

 

[Chrisphysics%]

There was a 41% increase in M>5.0 earthquakes in 2010 versus 2000. This excludes the years 1930 and 1900. It is also important to note that this claim is concerning stronger earthquakes, that are easier to detect. Projections for 2011 yield a 137% increase in earthquake activity when compared with 2000 for M>5.0. This is not a negligable increase.

The NASA-USGS report clearly states that melting glaciers may be clearling the way for increased earthquake activity.

 

[DaveC426913]

There was a 41% increase in M>5.0 earthquakes in 2010 versus 2000. This excludes the years 1930 and 1900. It is also important to note that this claim is concerning stronger earthquakes, that are easier to detect. Projections for 2011 yield a 137% increase in earthquake activity when compared with 2000 for M>5.0. This is not a negligable increase.

And this is not an analysis. You can't draw these kinds of conclusions like that (unless you're Fox News).

 

[D H]

And this is not an analysis. You can't draw these kinds of conclusions like that (unless you're Fox News).

Since this site is not Fox News, thread closed.

 

[Astronuc]

Are Earthquakes Really on the Increase?
http://earthquake.usgs.gov/learn/topics/increase_in_earthquakes.php

There does seem to be a trend of increasing activity, but it is not necessarily unique. Certain areas may experience a local increase over historic norms, but those norms are rather short term, since we did not have the ability to monitor seismic activity in such detail until recently (i.e. the past 4 or so decades).

I made two plots (based on data from USGS earthquakestats) of the frequency of earthquake (Mag 5+). One is a semilog ordinate, the other linear, as a function of year.

I imagine the extrapolation for 2011 is based on the 812 earthquakes (Mag 5+) during YTD, and the assumption that current activity would continue throughout the year. However, this might not be a realistic assumption. We will have to wait until December to see how this year plays out.