Thursday Video: Fracking!

The fracking issue in the United Kingdom is being reignited once again since the Chancelor George Osborne has shown in his Autumn Statement support to the the industry in this field, with tax advantages and other iniciatives.

I cannot have an opinion on this topic simply because I don't have enough information. But I find annoying how people who become specialists after reading two or three posts in a forum have a ground and solid opinion, not based on facts and data but on opinions of others.

How much of the arguments against fracking are pure myths? How much the economy really benefits from this shale production? Surely there are pros and cons, but like in many other topics, "controversy" many times is simple ignorance and fanatism. It reminds me the "controversy on evolution": There is not such controversy, full stop.
It's actually difficult to find reliable information on it.

Is Blackpool going to collapse? No.

Is fracking causing earthquakes? Perhaps Mw 2.3 or 1.5 events, but hardly anything that doesn't already occur naturally in the British Isles

Is the Large Hadron Collider kill us all? Well, do you see what I mean with "controversies". A controversy is good, it sparks debate. A "controversy" is not. I doesn't spark anything.

Most of sources are biased to one side or to the other, and hardly anyone speaks about the geomechanics behind, about the drilling technique, about the geology involved... The truth is that we consume more and more energy, and we need to get it from somewhere. We all know that oil and gas is a patch and not a permanent solution to our energy needs. But as long as we live in as we do now (heating systems based on gas, cars running on petrol), we need fossil fuels and this is not an option.

This week The Independent published a story that, in my opinion, is just bad journalism. "The great rush: Government to give green light to mass exploration for shale gas", simply don't talk about what is actually fracking. It just echoes the arguments of Greenpeace, and this is all. The media has been repeating that for two or three days now:

"They suggest more than 32,000 square miles – or 64 per cent of the countryside – could potentially be exploited for shale gas and is being considered for exploration licences."

So what? It doesn't mean that this 64% of countryside will contain profitable prospects. Most of the surface of any country is potentially open for exploration of mineral deposits, and we don't live in open pits, do we?

Unfortunately, geology is an unknown topic for the vast population. Hardly anyone stops to think "one moment... this earthquakes in Blackpool, CAN they actually be produced by some fluid injection in the rocks down my feet?"

This short clip I found in YouTube is quite appropiate for today. . It's an animation that illustrates part of a talk given by Prof. Mike Stepheson asking, precisely, for information. The public needs information, not ready-made ideas and opinions. And then, they will decide what is best.

http://www.youtube.com/watch?v=TKW4_UGVGBw

And yeah, keep wearing shorts and tshirt at home while outside is freezing. That really helps the debate.

Any opinion? Any good source of information? Let's discuss. :-)

I find the term "fracking" awesome. I think I will use it as substitute of the F word. "What do you think of this fracking shales thing, pal?"

Online plate tectonics

The Geological Society of London revamped their website a couple of months ago or so. It's basically the same site as before, but better organised and with a much nicer layout and design. Thumbs up for this!.

 

One of the things I like the most is the "Online plate tectonics" site, aimed to students aged 14 - 16 (I personally think any person will enjoy it, at any age). The site starts with an interactive introduction to the distribution of plate boundaries, volcanoes and earthquakes. It has also sections on the pioneers of plate tectonics, explanations about the geochemical and geomechanical properties of plates, and how the plate tectonics have shaped the geography of the United Kingdom. It also counts with tests and glossary areas, where the young visitor can check their knowledge and find answers to their questions.The teachers also have their area, with indications and guidelines.

A great initiative for kids, teachers and general public alike. It doesn't matter how much you know about plate tectonics, you will like this site and you will bookmark it!

Enjoy it and spread it.

http://www.geolsoc.org.uk/Home/Plate-Tectonics

6.9Mw earthquake in India, Nepal and Tibet

A 6.9 Mw earthquake hast struck India, Nepal and Tibet, causing at least 18 casualties. Much damage has occurred, and landslides have been triggered by the seismic event, blocking remote regions and breaking communication with the most affected areas.

Early calculations locate the hypocentre at 19.7 km depth, underneath the Sikkim region of India. The focal mechanism solution indicates a likely strike-slip movement in a fault which doesn't seem to be directly related with the India-Eurasia thrusting.

This earthquake is related with the convergence of the Indian subcontinent moving towards Eurasia, a phenomenon that causes the uplift of the Himalayan range.

More info at:

http://www.bbc.co.uk/news/world-south-asia-14967812

http://www.bbc.co.uk/news/world-south-asia-14967857

http://earthquake.usgs.gov/earthquakes/eqinthenews/2011/usc0005wg6/#summary

Callan explains you the Virginia earthquake

A great post from Callan Bentley's blog, describing the geological background of yesterday's earthquake in Virginia (USA), 5.8-5.9 magnitude:

http://blogs.agu.org/mountainbeltway/2011/08/23/the-mineral-va-earthquake-of-august-23-2011/

Earthquake strikes US east coast

5.9 magnitude earthquake in the East coast of USA. Some material damages but not casualties reported:

http://www.washingtonpost.com/earthquake-rattles-washington-area/2011/08/23/gIQATMOGZJ_story.html

http://www.bbc.co.uk/news/world-us-canada-14634730

Japan Earthquake Poster

USGS has published a poster of the Great Tohoku Earthquake in Japan of 11th of March 2011. It seems that the upgrade from 8.9 to 9.0 Mw is definitive, and like that appears now in most of documents from national geological surveys. (Link to the poster a the end of the article).
The poster is very interesting, and it compiles the basic tectonic/geophysical data needed for understanding an earthquake like this.

Find the poster here: http://earthquake.usgs.gov/earthquakes/eqarchives/poster/2011/20110311.php
PDF version for printing in a plotter: ftp://hazards.cr.usgs.gov/maps/sigeqs/20110311/20110311.pdf


(Thanks to Ángela Pañeda via Facebook!)

Japan has moved

Many newspapers and websites have published during the last days that "the Earthquake has moved Japan". Interestingly, most of journalists focus on the lateral movement, but forget the vertical displacement.

More and more data comes to light after the massive earthquake in Japan last week. As Callan Bentley points out in his blog, the vertical component of the displacement vector field shows a general subsidence in all the East coast of Honshu (Japan's main island). The maximum subsidence is 75 cm, while the horizontal displacement has been of up to ca. 4.4 m (eastwards).
At first sight, it could look awkward, as the affected part of Japan is in the Okhotsk Plate, which is the overriding plate, while the Pacific plate is the subsiding element. Shouldn't the overriding plate uplift, instead of subside? Let's analyse it more in detail.

A megathrust fault is the tectonic boundary between a subsiding plate and an overriding plate. Megathrust faults are the causing element of the majority of most powerful earthquakes in the Earth. Probably, the most famous megathrust is beneath Cascadia in North America, and you can find most of the information you need about that in this great site: Giant earquakes of the Pacific NW.

Coming back to Japan, which is part of the Eurasian plate, it overrides the Pacific plate over a megathrust. This is the fault that, with its slip due to elastic rebound, caused the 9.0 Mw earthquake some days ago. But of course, the slip occurs suddenly, after accumulating energy for certain time.

As the following figure shows (taken from here), the overriding plate develops a bulge -due to strain build-up- when the upper plate locks over the subducting plate. Behaving elastically, the bulge grows as shortening continues, and the overriding plate continues accumulating strain in the bulge area. At some moment, the contraction is so strong that it exceedes the hold of friction along the fault, and an earthquake is triggered. The strain build-up relaxes, and the previoulsy uplifted region subsides. The cycle starts all over again.

This is what has happened in Japan. An example may be to imagine ourselves pushing a mat, with our feet, against another mat. One of them will form a fold in the rim, until its resistance is broken, it slips over the "subsiding" mat, and the fold disappears.

In 1700, that happened in Cascadia (http://blog.lib.umn.edu/stgeorge/geog5426/2010/11/13/Jacoby%20Geology/201997.pdf), when a massive earthquake caused the subsidence of a region, where many trees drowned and just a handful of them survived... for telling us through their ring what happend with the topographic base level. (Photo from here)

NASA has published two MODIS images, showing the coastline in Sendai before and after the eartquake. It is still early to estimate the new coastline, as in the images of this week many lands near the coastline are still flooded by the tsunami wave, and will probably not be submerged in the near future.

Before (26th Feb. 2011)After (12th March 2011)

Shorter days caused by earthquakes?

The powerful earthquake of 11th of March in the island of Honsu (Japan) has shortened the day length in 1.8 µs (microseconds, or millionths of a second), has declared Richard Gross from NASA's JPL in Pasadena, CA (USA). Gross has calculated the change in inertia moment, after the deadly earthquake has changed the distribution of Earth's mass.

The massive earthquake has also affected the geometric axis of our planet, which could have been moved up to 17 cm.

"In theory, anything that redistributes the Earth's mass will change the Earth's rotation," Gross said. "So in principle the smaller aftershocks will also have an effect on the Earth's rotation. But since the aftershocks are smaller their effect will also be smaller."

Gross had also calculated in the past displacements of our axis and variations of our day length, following large earthquakes in Sumatra and Chile.

My question is: Does this actually happened? Do this calculation involve astronomical measures that certify the change, and if so, its magnitude? Is this earthquake strong enough to vary the angular inertia of the planet?

Any insight? Please, comment.

You can read the full story at SPACE.com,

Are there more earthquakes in our days? Is the end of the world here?

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. Note that the graphs DO actually show an increase, but this increase is more probably related to the number of registered earthquakes, and not to the actual seismic activity.
• 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!

Source of the graphs: http://earthquake.usgs.gov/earthquakes/eqarchives/year/graphs.php

Honshu earthquake and tsunami in Japan, 8.9 Mw

One of the strongest earthquakes in recent history ( 8.9 Mw) has struck Japan some hours ago, and surely you are well informed by now. In any case, you can find up to date information in the following websites:

English:
http://www.bbc.co.uk/news/world-middle-east-12307698
http://www3.nhk.or.jp/nhkworld/

Japanese:
http://www3.nhk.or.jp/

Spanish:
http://www.elpais.com/

The tsunami alert has been extended to most of the Pacific, where people are strongly advise not to stay along the coasts.


Tectonic Summary
The 03/11/2011 earthquake (preliminary magnitude 8.9) near the east coast of Honshu, Japan, occurred as a result of thrust faulting on or near the subduction zone interface plate boundary between the Pacific and North America plates. At the latitude of this earthquake, the Pacific plate moves approximately westwards with respect to the North America plate at a velocity of 83 mm/yr. The Pacific plate thrusts underneath Japan at the Japan Trench, and dips to the west beneath Eurasia. The location, depth, and focal mechanism of the March 11 earthquake are consistent with the event having occurred as thrust faulting associated with subduction along this plate boundary. Note that some authors divide this region into several microplates that together define the relative motions between the larger Pacific, North America and Eurasia plates; these include the Okhotsk and Amur microplates that are respectively part of North America and Eurasia.

The March 11 earthquake was preceded by a series of large foreshocks over the previous two days, beginning on March 9th with an M 7.2 event approximately 40 km from the March 11 earthquake, and continuing with a further 3 earthquakes greater than M 6 on the same day.

The Japan Trench subduction zone has hosted 9 events of magnitude 7 or greater since 1973. The largest of these was an M 7.8 earthquake approximately 230 km to the north of the March 11 event, in December 1994, which caused 3 fatalities and almost 700 injuries. In June of 1978, an M 7.7 earthquake 75 km to the southwest caused 22 fatalities and over 400 injuries. In December of 2008, a sequence of 4 moderate earthquakes (M 5.3-5.8) occurred within 20 km of the March 11 event. In the first 12 hours following the March 11 earthquake, the region has experienced over a dozen aftershocks of M 5 or greater, the largest being M 5.7.


Scientific data about the earthquake, from USGS

11/03/11 5:46:23

Epicenter: 38.321 142.369

MW 8.9

USGS/WPHASE CENTROID MOMENT TENSOR

11/03/11 05:46:23.00

Centroid: 37.321 141.769

Depth 24 No. of sta: 89

Moment Tensor; Scale 10**22 Nm

Mrr= 1.16 Mtt= 0.18

Mpp=-1.34 Mrt= 1.33

Mrp= 2.17 Mtp=-0.10

Principal axes:

T Val= 2.88 Plg=55 Azm=313

N = -0.08 11 205

P = -2.79 32 108

Best Double Couple:Mo=2.8*10**22

NP1:Strike=162 Dip=17 Slip= 45

NP2: 28 78 102

Source: http://earthquake.usgs.gov/earthquakes/eqinthenews/2011/usc0001xgp/#details

Geological map of Middle East and Arabia

One of the areas in the world where I work the most doing geological maps from satellite images or constructing balanced cross sections from our own maps or from seismic lines, wells, etc, is the Middle East (chiefly in the Kurdistan Region in Iraq, in Iran, in the whole of Turkey, Syria, Yemen...).

This morning, looking for a nice map to put up of my wall in the office, I found this link, which surely will be very useful to anyone looking for a small scale* geological map of Arabia and the Middle East.

Commission for the geological map of the Middle East: http://www.cgmme.com/

The link includes jpeg and pdf versions of tectonic, geological and seismic maps of the Middle East and Arabia.

I hope this is useful for you.

*Remember! 1:1.000.000 is a smaller scale than 1:25.000!

Strong earthquake hits New Zealand

A 7.0 earthquake has shaken New Zealand today, two hours ago. More information at BBC.

From the USGS.gov website:

New Zealand earthquake occurred as a result of strike-slip faulting within the crust of the Pacific plate, near the eastern foothills of the Southern Alps at the western edge of the Canterbury Plains. The earthquake struck approximately 50 km to the west-northwest of Christchurch, the largest population center in the region, and about 80-90 km to the south and east of the current expression of the Australia:Pacific plate boundary through the island (the Alpine and Hope Faults). The earthquake, though removed from the plate boundary itself, likely reflects right-lateral motion on one of a number of regional faults related to the overall relative motion of these plates and may be related to the overall southern propagation of the Marlborough fault system in recent geologic time.
Today's earthquake occurred approximately 50 km to the southeast of a M7.1, surface-rupturing event in Authur's Pass, on March 9th, 1929, which caused 17 fatalities. More recently, two earthquakes of M6.7 and M5.9 occurred in June 1994 approximately 40 km to the northwest of today's event, but did not cause any known fatalities or significant damage.

http://earthquake.usgs.gov/earthquakes/eqinthenews/2010/us2010atbj/

Free papers on Chile and Haiti provided by The Geological Society of London

The Geological Society of London has made freely available two sets of papers at their website, related with the earthquakes ocurred in Haiti and Chile in the past weeks and months. Together with these papers, you can also download a series of publications related with the bicentenary of Charles Darwin:

http://www.geolsoc.org.uk/gsl/publications/lyellcollection/page7188.html

These papers will be available for free until the end of March (Darwin and Haiti topics) and until the end of April, in the case of Chile.

¡Arriba Chile!

More than 700 casualties have been counted so far due to the earthquake of last Saturday. Now is the moment to contribute with any help you can give: Remember that any amount of money is useful. "A beach is made of grains of sand".

If you want to help contributing online, use the Google Crisis Response site dedicated to this earthquake:

http://www.google.com/relief/chileearthquake/

You can also visit your local/national Red Cross organisation:

http://www.icrc.org/

Please, help and forward this message to your contacts and friends.

http://www.boston.com/bigpicture/2010/02/earthquake_in_chile.html
AP Photo/Roberto Candia

Earthquake in Chile, 8.8 Mw

Chile has been shaken this night by a 8,8 Mw earthquake, as reported by www.usgs.gov (http://earthquake.usgs.gov/earthquakes/eqinthenews/2010/us2010tfan/#details). There is not much information so far. Bachelet, president of Chile, has reported 6 casualties already. USGS informs of potential several structural damages in central and southern Chile.

The epicenter has been located at 35 km offshore Concepción, and Santiago de Chile, at more than 300 km, has been left in a blackout. In Valparaiso, the quake has been felt, but apparently no major damages have been reported.

Chile has been always, and will be, one of the most seismologically active areas in the world. In 1960 a 9.5 Mw earthquake devastated the region of Valdivia, killing 1655 people.

http://earthquake.usgs.gov/earthquakes/eqinthenews/2010/us2010tfan/#scitech

M6.3 earthquake in Taiwan

If you have been listening to the news in the last hours, you probably know already that a M6.3 earthquake has struck offshore Taiwan. As usual, the best information comes from the USGS.

The event happend at 18.05 UTC, and we don't yet have a focal mechanism solution for it. Anyway, in the attached figure you can have an idea of what is going on in there.

Taiwan is located in the boundary between the Phillipine Sea and the Eurasian plates. There is an approximated convergence rate of 80 mm/yr to the SE. What is really especial about this island is the presence of two subduction zones: One, where the South China Sea subducts beneath Eurasia, and another one, where Eurasia subducts beneath the South China Sea, forming both zones approximately a right angle.

You can see a great introduction (including the previous explanation) to the geology of Taiwan in the dedicated website of the California Institute of Technology:

http://www.tectonics.caltech.edu/taiwan/regional.htm


Sources:

- http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/us2009jabu.php
- http://www.tectonics.caltech.edu/taiwan/regional.htm

Earthquakes in Google Earth

A good habit I have acquired during the last months is to take a look to the recent seismic activity of a region before starting to work in there, in order to get a quick idea of what is going on. This habit can be more illustrating that it initially seems.

USGS provides a KMZ file with a very friendly and attractive interface for Google Earth. It loads the major earthquakes in our planet for the last 7 days, classified by time (Last hour, Last day, Last week), and by magnitude (from 1 to 8). If you click on each individual earthquake, you will open a box with its basic information and the url link for opening in your browser the complete information about it.

You can load this file in your Google Earth from the dedicated USGS website for seismology:

http://earthquake.usgs.gov/

It is on the left, "Google Earth KML". Anyway, the direct link to the file is:

http://earthquake.usgs.gov/eqcenter/catalogs/eqs7day-age.kmz

The interface also loads plate boundaries and convergence rates, measured in mm/year. I haven't found the source of the rates, but let's accept that if the data comes from USGS, should be fine. The plate boundaries included in the KMZ file are:

- Subduction zone.
- Oceanic transform fault.
- Oceanic spreading rift.
- Oceanic convergent boundary.
- Continental transform fault.
- Continental rift boundary.
- Continental convergent boundary.

Of course, don't expect a very precise location for the plate boundaries! It is just an indication of the global tectonics of each area, in order to put the earthquakes in a correct geodynamic context.

Personally I find this KML file very useful, not only for the very up-to-the-date information given, but also for the boundaries, the rates... Useful thing when we have to prepare a simple figure in Corel or Freehand for a report.

Again, the links:

http://earthquake.usgs.gov/
http://earthquake.usgs.gov/eqcenter/catalogs/eqs7day-age.kmz

There are more KML's and KMZ's providing similar information, but that will be for another day.

Enjoy!

Mw 6.3 Earthquake in Italy

We got up this morning with the terrible news from Italy, where last night an earthquake affected significantly the location of L’Aquila in the Central Apennines region resulting in more than 90 killed (so far, at 14.00 GMT, and surely the number will increase in the next hours).

The Apennines are an accretionary wedge formed as consequence of the subduction of the Adriatic microplates under Italy from east to west, whilst from the south to the north the convergence of Africa against Europe builds the Alpine orogen and opening the Tyrrhenian sea to the west of the Italic peninsula.  

I won’t extend much in this entry; you can read better and more updated information in the news:

Powerful Italian quake kills many (BBC website)

Magnitude 6.3 – Central Italy (USGS website)

"Eine verlässliche Vorhersage war es auf keinen Fall“ (Tagesschau.de, in German)

Sadly an Italian geophysicist predicted the event –kind of–. We cannot rely on predictions. We cannot expect –yet– to trust correlations between indirect measurements and seismic phenomena. What we can do?

What we can do as geologist is help the authorities educating people, promoting the knowledge of geohazards and how to behave in the case of an Earthquake. Authorities have in their hands the power of approve correct standards for construction. A 6.3 earthquake shouldn’t have caused any fatality in a rich country like Italy. Why it has been like that? Seismicity in the Central Apennines is not new. Historic earthquakes include the one  of 1997 (Mw 6.0) which includen in a period of 2 months several M5.0 events (the Umbria-Marche seimic sequence).

Our support to the people in despair for this earthquake.

(Later I will update this article with some images and corrections... I am sending this from my email!)

Tonga and bad science

In the recent weeks we have witnessed through the media the eruption of the Tonga submarine volcano reaching the oceanic surface. Spectacular images make us feel small in this wonderful planet. The volcano is emerging day after day and, as reported by Associated Press, it is located at 10 km from the main island, Tongatapu, in a cluster of nearly 60 other volcanoes.

A few days after after the volcano got protagonism, the media also informed of a relevant earthquake in the area, happened on the March 19th, 2009. A 7.6 magnitude earthquake shaked the conctact between the Pacific, also in the vicinity of Tonga.

Well. No. Not really. I mean, yes, it happened, but not in the "vicinity of Tonga". It happened 260 km of the location of the volcano. Anyone with a slight knowledge of geology would think: "Yeah, they are close, relatively, but surely not related at all".


This thought didn't pass through the mind of the responsible of choosing the title of the news in the BBC website...: Quake may have caused eruption. Well, why do they choose this title if the video doesn't make any connection between both events? Very few people would have seen the video (hey, it's science, not a celebrity in Cannes), and most of the readers have kept in mind just that: The earthquake and the volcano may be related.

It is hardly explainable how an earthquake in such a tectonic framework (an oceanic convergence) can cause, or trigger, or affect a volcano 250-300 km away. Both phenomena are perfectly understandable if we take them independently. So, why the story in the news? Possibly is easier to sell the story like that.

I remember how difficult is to explain people how two events can happen at the same time but be absolutely independent: "Sorry, are you saying that the tsunami in Sumatra is not related with global warming? but... surely is related. We destroy our planet! And anyway, you work with satellites, you haven't been in the field". Argh.

Anyway, the good news is that there is not any material harm, and general news are talking about geology. Woohoo.

(Reading about the Tonga volcano and the earthquake I got know the blog of Maria Brumm, "Green Gabro". Take a look, is well worth doing it)