The Lisbon Structural Geologist

I am not the only one!

2011-09-16T11:57:00.000+01:00

I have just received an e-mail from a colleague of mine, suggesting me to change the title of this blog from “The Lisbon Structural Geologist” to “A Lisbon Structural Geologist”… Since I am obviously not the only structural geologist that lives and works in Lisbon, and since it is apparent that the former title could induce the readers in such a mistake, I have decided to change it in accordance.

Ken Robinson's view on this thing we call "education"

2011-05-05T10:40:00.000+01:00

This video really deserves the little time it takes to watch, particularly if you are in some way connected to the activity we call “education”.

About the new(?) armies of low-paid PhD researchers

2011-01-13T09:38:00.000Z

A must read paper in The Economist: "Doctoral degrees: The disposable academic"

Photos of the Swiss Alps #1: geologists climbing the mountain

2010-12-10T11:40:00.001Z

The academic semester is ending soon. So I hope I will have time to resume my blogging activity, and to share with you all the geology photos of this late August Swiss Alps field trip.

Reorganization

2010-09-18T16:23:00.002+01:00

I obviously haven’t been able lately to maintain this blog, or to pay attention and read - as much as I would like to - other (geo) blogs.

A lot of other more important things got in the way. Among them: the end of my one year sabbatical license, the submission of one paper and the desperate attempt to submit another until the end of last July (before my summer vacations), a geo field trip in the Swiss Alps and, most important, the resume of my teaching activity at UL this semester.

As a result I had to reorganize myself considering what to do with the LSG blog. I decided to try to update it with at least one geo-photo post once per week, and with a more insightful contribution at least once per month.

Today’s photo depicts the famous Glarus thrust (near Flims in Switzerland) and will soon be followed by a more detailed report of the late August 5-day field trip in the Swiss Alps, to which I was invited by Prof. T. Nagel (Bonn University).

I will write about the people, the mountain, important outcrops, papers I have read concerning the several problems I was introduce to, etc.

I am planning to do this during the following semester, hopping to be able to interest UL students aiming at organizing a similar field trip in the summer of 2011 or (most probably) 2012.

Let’s see how it works out in view of my dramatic lack of time!

New header

2010-06-27T14:55:00.006+01:00

Following a comment by Silver Fox on my previous post (The amazing geobloggosphere), I have modified the blog header, besides having slightly changed the sequence by which information is displayed. I know I have to do more and better, but right now this was just what I had time to do.

Old LSG header

New LSG header

Could you tell me what do you think of it? Better or worst?

By the way, the slow load difficulties reported by Silver Fox are they general? Does it happens with everybody? (If that is the case, I am really going to try to get some help to quickly solve this. Not being able to look at other pages while this one is loading really sucks!)

I thank everybody in advance for all incoming opinions.

The amazing geobloggosphere

2010-06-24T20:53:00.001+01:00

Since I have started my (geo)blogging activity several friends and colleagues have insistently asked me why do I blog, and how can I afford loosing the amount of time it involves.

I try to explain them the incredible feeling of having discovered a whole new world.

[A world where one can find Earth-scientists from many different countries, motivated by their passion for what they do geo-related, regardless if it is geochemistry, volcanology, sedimentology, structural geology, seismology, or whatever more.

They are field geologists, industry research employees, college teachers, graduate students, post-docs researchers, university professors, etc.]

Recently, a new (to my knowledge) AGU blog: “The Plainspoken Scientist” has invited several geobloggers to explain just that, i.e.: Why do they blog, and what motivated them in the first place to start doing so.

The first three contributions (Mountain Beltaway, Magma Cum Laude and Clastic Detritus) are really worth reading, and constitute a good summary of reasons, with which I definitely can identify.

Myself, I have created a geoblog after I started to follow Clastic Detritus. I do it because I love geology and I want to enjoy it beyond the realm of the academic institution in which I work.

The opportunity to share thoughts, photos and all kinds of information and experiences related to my professional activity as a geologist with people all over the world who share similar interests, really revealed itself as a source of immense pleasure and fun. And honestly this was (and is) my prime motivation. Divulging geosciences, helping students, getting help on different subjects are all also important but, honestly, they all come second to the pleasure of knowing that there is someone out there – in fact a whole lot of people – who makes some sense of what I do (regardless of their specific opinion about whatever particular topic).

[The lyrics of an old TV-series “Cheers” conveys the feeling in the passage (perhaps better if one substitutes “troubles” by “interests”):

“You wanna be where you can see,
our troubles are all the same
You wanna be where everybody knows
Your name.”]

Finally I would like to leave a question to the (much more experienced) geobloggers (and to the others): What is the average of visitors per day of your blogs? How did this evolved over time since you have started to blog? How important is this for you guys? I’d love to have your answers on this (delicate?) matter. Thanks.

M5.0 earthquake near OTTAWA, Ontario, Canada

2010-06-24T00:37:00.002+01:00

As usual all relevant information can be consulted here.

The USGS tectonic summary talks about reverse-fault reactivation of a previous normal fault of the NW trending Ottawa graben, and explains that earthquakes of this magnitude, although having had occurred in the past, are relatively rare in this area (east of the Rockies), distant from any main tectonic boundary.

The earthquake was relatively shallow (~16km depth) and located only 56km NNE of Ottawa. So I can imagine from my own recent experience that it might have frightened quite a few.

USGS historical record of the largest events in this same area mentions a M6.1earthquake in 1935, and a M6.2 in 1732, respectively to the NW and to the east of the today's location (at a mean distance of ~200km). Only the 1732 earthquake is reported to have caused "significant damage in Montreal".

In my last post I mentioned that I have an aunt living in Toronto (located ~350km to SW of Ottawa), well judging from the project of t-shirt that she sent me only a few hours after the quake (on the left), the inhabitants of this great city sure live up to their high spirits' reputation!

I am reading… “The Earth After Us – What legacy will humans leave in the rocks?” by Jan Zalasiewicz

2010-06-20T02:41:00.006+01:00

Portugal is going through a severe financial and economic crisis. You can read all about it in the press (national and international), and I promise you this post is not about that!

But concerning this subject is very easy to read about the imminent, fatal catastrophe that will inexorable fall upon all our heads if we don’t behave.

[now I really have to restrain myself from discussing what behave means, from defending the European social security system that the same guys that caused the crisis say is not possible to sustain, etc., etc. … again: this post is not about that!]

It is about what I call the anthropocentric character of all these opinions, i.e., the inability of the vast majority of the well educated opinion makers to remember (or, I suspect, in most cases to realize!) that our species (as has happened with all the others in our planet) within a very brief interval of geological time will almost for sure disappear.

What I mean is that all geologists know that Homo sapiens sapiens will briefly (in geological terms) most probably be extinct.

For those of you non-geologists who are less familiar with geological time, a very small list of dates to trigger your interest (this is a super super summarized list of important events):

- (most) Cosmologists say the Universe started with the Big Bang at 15 000 million years;

- The age of the Earth corresponds closely to one third of that time (4600 million years);

- The first forms of life (prokaryotes) are generally thought to have appeared on the Earth between 3000-4000 million years;

- Multicellular organisms did not exist until ca. 610 million years and;

- Modern man (Homo sapiens sapiens), biped apes with big brains that love to use instruments, are only around since 200 000 years (the lack of the word million after the number is not a mistake!).

If you’re not a geologist take a break to think about these numbers. Compare 200ky with 100My that corresponds approximately to the time of dominance of dinosaurs on the Earth. Take your time, think about it.

How do you feel? Getting a grip of how hugely insignificant we are in geological terms now? Take it easy we’re not extinct yet, and mean while I recommend the use of a small parcel of the time we have left to read the beautiful book by Jan Zalasiewicz “The Earth After Us – What legacy will humans leave in the rocks” (an offer from an aunt of mine that lives in Toronto, who has paid me a visit in Lisbon a few weeks ago).

(left) - Dr. Jan Zalasiewicz (photo from here)

The book uses, as an excuse to explain the geology of our planet, the premise of an intelligent alien civilization finding Earth one hundred million years from now – i.e. long after our extinction as a species - and their efforts to learn about our planet through reading its history on the rocks.

What impact would we have left? What impression would we have made? What would be our legacy in the eyes of these alien guys?

The book which was first published in 2008 (many of you might have read it already), is not a science fiction book; make no mistake about it. Although its main premise is speculative enough (alien civilization finding our planet, etc.), it functions merely as a pretext to explain with unbelievable simplicity some major concepts of modern geology.

How and why is an important parcel of the history of our planet preserved in the strata? How rare is this compared with other solar system planets? What is plate tectonics, and why does it exist on Earth, and not on Venus or Mars? What are the implications of this for the existence of life? These are all examples of interesting discussed topics, always contemplated with the concern of making sophisticated concepts accessible to everyone with a curious mind: one of the most productive ways to shake the depressive feeling arising from realizing our (nevertheless quite obvious) finitude as a species!

[Then again we are the product of thousands of millions of years of evolution. One strange product since in our case, through such an evolution, matter has acquired at least some degree of consciousness of itself, and of its surroundings. There is absolutely no precedent in the history of the Earth (and elsewhere in the Universe?). So maybe, just maybe, this will make a difference, and one hundred million years from now we will be exploring other stars. At least that’s what I like to think about it when I look at my kids]

A bad day of work (thoughts on the war inside your head when you're writing a paper)

2010-06-18T18:20:00.003+01:00

(left) – This is me standing next to a poster, during the last GeoMOD meeting (Florence 2008), where I first presented the ideas I am writing about in the paper I am struggling with in the present moment.

Sometimes after an involuntary break (usually some type of bureaucracy) I find it very difficult to resume my work, particularly when I am writing a science paper.

When I am writing, I am constantly reviewing every step of the way inside my head, often taking forever to be reasonably satisfied with one particular way of expressing an idea, or describing an observation. It a harsh, recurrent and instantaneous interior conflict, a constant fight between what I keep expecting to able to do, and the result that in fact I am being able to produce.

I suppose everyone involved in any kind of creative intellectual activity, scientific or artistic, is more or less familiar with this (or similar) tension (ask PhD students writing their thesis and they’ll probably start talking about its potential destructive nature!).

So, when you are submerged within this private battle – often a bitter, vicious one – and you have to interrupt this pungent activity to take care of, for instance, learning the new rules for applying for funding of next semester science projects, as important as this might be (and it is!), it is a totally different world form the one you’ve been inhabiting in your preceding writing moments (minutes, hours?).

It is often such a brutal break that it feels like something is lost inside your brain. The awakening to the mundane world of everyday tasks bears with it the price of not remembering - at least not so well and not as fast - all the tiny details through which we were intending to explain a certain thought. It’s like a certain degree of familiarity, or a certain flavor of a particular important idea is, at least momentarily, lost.

As a result, resuming the writing is difficult. It takes time to regain a certain momentum, and a strong concentration. Sometimes – in what I call bad days of work – I find myself incapable of doing so…

… as in this precise moment (hence I blog!)

It is starting to look like Middle Age!

2010-06-16T11:22:00.005+01:00

The easiest way to make everyone forget the governmental responsibilities in minimizing the destructive consequences of natural catastrophes like earthquakes is to blame the scientists!

What about providing information to the population in high risk areas, repairing old buildings and constructing new ones according with the approved standing rules, promoting specific school educational programs, etc.?

Well the awnser seems to be: Sorry to expensive, it's cheaper to prosecute the scientists who were unable to predict the catastrophe!

Against this unacceptable reasoning that seems to be making its course in Italy (see here), I invite you all to sign the following "Letter of support for Italian earthquake scientists indicted for failing to predict the L'Aquila Earthquake". You can use the foolowing link: http://www.mi.ingv.it/open_letter/, and I reproduce the text below.

"Dear colleagues and friends,

Two weeks ago the L'Aquila Prosecutor's office indicted of manslaughter the members of the National High Risk Committee that met in L'Aquila one week before the Mw6.3 earthquake.

The charges are for failing to provide a short term alarm to the population before the earthquake struck, killing more than 300 people.

The president of INGV, Enzo Boschi (member of the High Risk Committee), and the director of the National Earthquake Center, Giulio Selvaggi (just accompanying Boschi to the meeting as technical specialist), are among the scientists in seismology and earthquake engineering now under investigation together with some civil protection officials.

We think that the allegations against the scientists are completely unfounded and we look for support on this from the international scientific community working on earthquakes and in the Earth sciences in general.

We invite you to sign the letter addressed to the President of the Italian Republic, published at the the www.mi.ingv.it/open_letter/ . We also would be glad if you could extend this invitation to other seismologists that can possibly share our initiative.

We hope that by this action we can increase the awareness of people on earthquake risk reduction through education, preparedness, and a long term program of building reinforcement.

Thank you in advance for your support

Daniela Pantosti
Alberto Michelini
Alessandro Amato
Massimo Cocco
Ingrid Hunstad
Warner Marzocchi
Claudio Chiarabba
Massimiliano Stucchi"

What does dinosaur extinction has to do with industrial activity?

2010-06-05T12:36:00.004+01:00

New Zealand geologist, Mark Harvey, reports new scientific data according to which classic indicators of industrial activity, found in the K-T boundary (Cretaceous-Tertiary extinction), allow the discarding of global fires as being associated to the dinosaurs end, 65My ago. Instead, the Chicxulub asteroid is thought to have hit massive oil or coal deposits. Read more about it here.

(left) - KT boundary exposed by erosion in badlands near Drumheller, Alberta. Photo by G Larson (obtained from Wikipedia)

No relation with geology... but too important and too good to ignore!

2010-06-04T13:20:00.004+01:00

Everyday stuff amid sunny hot weather

2010-06-04T12:38:00.000+01:00

Left - Cape S. Vicente SW of Portugal (view from North)

I have been without posting for a while now (since I have returned from the Vienna EGU meeting) but I will now resume my blogging activity. It has been a rough period with a lot to do.

I am presently working in two papers concerning the tectonics of the Gulf of Cadiz region (i.e. the Iberia-Nubia plate boundary in the SW Iberia offshore). They both involve analogue modeling, and one of them also includes some 3D numerical modeling results. Both papers are the result of a wide collaboration with different colleagues of different institutions, and I’ll let you know all about it as soon as I submit the work (my mental dead-line is 1^st of August, and at least one of them WILL be submitted before that, as for the other one I am fighting hard… I am fighting hard…)

Left - Sand ripples in Beliche beach near Sagres (SW Portugal).

Besides this I have been working in other stuff like preparing the discussion of a PhD seminar to the jury of which I was invited, discussing and writing abstracts to the next GeoMOD meeting (which dead-line submission was by the way postponed to the 15 of June!), helping undergrad students with their end term reports, preparing bureaucratic academic meetings of the Faculty Assembly (of which I am a member).

Left - Crescentic scour-marks in the sands of Beliche Beach (SW Portugal)

Mean while I have been reading a lot about the tectonics of the Alps, since I will participate on a field course next August with Prof. T. Nagel and his students from Bonn University. I am really looking forward to see - with my own eyes - the beautiful structures of the most exhaustively studied European Orogen.

Right - Beliche beach in SW Portugal: the dots in the water are surfers waiting for the right wave)

In Lisbon it’s very hot! And one starts do day dream about the beaches in the south of Portugal: two more months of really hard work and I’m off with my family to 3 weeks of just that (besides the geology in those beaches is amazing, and one can even look at the outcrops from inside the water!)

A true Portuguese hero at EGU 2010

2010-05-07T16:22:00.000+01:00

The path walk connecting the nearest subway station (Kaisermuhlen VIC) to the Vienna Centre, where the EGU meeting is still taking place, has the name of a true Portuguese hero: Aristides de Sousa Mendes.

Aristides de Sousa Mendes was no geologist or geo-scientist of any kind, but a Portuguese diplomat in France who ignored and defied the orders of his own government, led by the fascist dictator António de Oliveira Salazar, guarantying the safety of thousands of World War II refugees, including thousands of Jews, seeking shelter and salvation from the Nazi German invader. “Between June 16 and June 23, 1940, he frantically issued Portuguese visas free of charge, to over 30,000 refugees seeking to escape the Nazi terror, 12,000 of whom were Jews.” (Source: Wikipedia).

Adding to my great satisfaction (in general terms) in having attending this EGU meeting (I will post an overview opinion of the meeting when I get home), it felt great to learn that a true Portuguese hero was justly being remember in Vienna.

The peak

2010-05-06T15:57:00.001+01:00

(Left) Vienna International Center across the Danube today at lunch time (around 12).

My peak moment so far in this year EGU meeting was the yesterday’s modeling session (oral and poster) concerning physical and numerical modeling of crustal processes.

I was truly impressed by the work presented by David Boutelier (GFZ Potsdam) who presented some up-to-the-date results of physical modeling, but of a totally different and fundamentally new kind (at least to my knowledge). Here’s why:

If you read the introduction to this EGU section (to which I have referred in a previous post) you’ll realize that one of the reasons why physical (analogue) modeling is considered a useful insightful tool, is that it allows a 3D characterization of the structures and geological processes at stake, which is still fairly difficult to achieve with a satisfactory efficiency through numerical modeling techniques alone.

(Left) - Surfing the net at Vienna center

On the other hand, traditionally in physical (analogue) modeling rheology is not temperature-pressure dependant since those gradients, which strongly influence the considered rheological stratigraphy (for instance at lithospheric scale), are simulated by the choice of the appropriate analogue materials (for instance: sand is generally chosen to represent the brittle behavior of the upper crust, silicone putty is often used to mimic the mechanic behavior of natural salt, etc).

Well, the novelty of D. Boutelier’s work is that he preformed 2D and 3D thermo-mechanical laboratory experiments on subduction and exhumation processes (check the abstract here), comparing these new models with purely mechanical ones and showing the significant differences involved. This is an advance kind of physical modeling involving materials which P-T dependant properties approach the scaled rheology profile of the lithosphere. In the presented experiments the materials reflected the change in the mechanical properties that rocks endure during subduction. The technical details are also exciting and comprise a complex lab apparatus in order to achieve differently heating of the materials from beneath (a kind of electrical heater) and from above (some kind of special lamps if I remember well).

(Left) - Down view on this year EGU vendors

I am definitely waiting this amazing piece of work to come out (David explained to me later, during the poster section, that he is in the process of writing it). Well, congratulations David and thank you for sharing your exciting results with the rest of us!

EGU meeting: I am finally here

2010-05-05T11:36:00.002+01:00

Conversely to what I had predicted I only arrived in Vienna yesterday evening.

(Left) The Vienna Center this morning at 7H45AM

Today, I arrived at Vienna Center a little before 8:00 AM and took care of my registration in a minute, got my badge, that gives me full access to the meeting premises, and my transportation pass, that allows me to travel in all public transports through Vienna during the period of time correspondent to the duration of the meeting.

During the morning of this first day I divided my time between attending to the session "GD4.2/TS5.5 Processes along passive margins and Links with Onshore Uplift" and session "TS6.1/G18/GD5.4 The Alpine-Himalayan orogeny: from the Mediterranean to SE Asia". I regret these were held at the same time. I am very much interest both in lithospheric extension and orogenic collision (and I suspect I am not the only one!). So it was kind I of annoying to “jump” between rooms 30 and 31 during all the morning.

(Left) - Entrance of room 31

As for the sessions themselves, I found most of the presentations very interesting indeed, and I really enjoyed several different angles on the tectonics of the Mediterranean (including analogue and numerical modeling approaches).

(Left) - Entrance of room 30

I only (really) regret the persistent lack of time for questions and discussion. This was almost with no exception sacrificed in the name of the (sacred?) demand “of being on schedule”. I understand this need, especially in this kind of massive meeting, but I really think some tolerance for the sake of discussion, which is really the reason why we do these reunions, should be better accommodated.

This afternoon I will attend to the crustal modeling session, which is really the main reason for me to be here. I let you know in a future post.

The LSG on the 2010 EGU meeting

2010-04-30T10:34:00.006+01:00

Next Monday I'll arrive in Vienna (Austria) where I'll attend to this year EGU (European Geosciences Union) meeting.

The Lisbon Structural Geologist was included in this year's EGU blog roll, and I'll be posting my opinions regarding the several sessions and events that I will attend to.

My attention though, will be focused on TS9.2/GD2.6 The evolution of structures in the crust: insights from analogue and numerical modeling where it will be interesting to anticipate (at least in part) the excellent discussion regarding modelling in geosciences that I expect will take place in Lisbon next September (GeoMod2010 meeting).

I will only arrive in Vienna on Monday afternoon, so my first day in the meeting will be Tuesday. If you have any suggestions regarding the several sessions or any other events in EGU please let me know. By the way, are there any other geobloggers out there participating in the meeting? Is the strong North American geoblogger community absent of EGU?

Photos of geological structures - SW Portuguese coast (#3): Boudins and tension gashes

2010-04-27T14:43:00.003+01:00

I want to thank everybody that commented on the last post and, as I promised to some of you, I am now adding some more structural details to the same problem: In the necking zones of the folded boudinaged layer (depicted in the last photo of my last post) it is possible to observe en-échelon sigmoidal tension gashes (Figs A, B and C on the left). Are these synchronous with the boudinage? Or are they caused by subsequent extension during a later event, in which dextral right-lateral shearing localized along previously formed weaker (necking) zones? Note that the tension gashes cut the axial-plane fold cleavage.

Photos of geological structures - SW Portuguese coast (#2): boudins

2010-04-23T21:33:00.008+01:00

Imagine a geological sandwich of a competent (high viscosity) layer of rock, interbedded within two low competent (low viscosity) ones.

Fig.1 - Chocolate tablet boudinage pattern in Carboniferous sandstone (Almograve beach, SW Portuguese coast)

Now imagine that you stretch this sandwich by submitting it to extensional forces (you can imagine pulling in opposite directions both edges of our geo-sandwich, or squeezing it along the direction perpendicularly to its tabular shape).

What happens in the inner high viscosity layer? (Keep in mind that a sandwich is an ultra simplification of reality, namely because in nature we would be dealing with a much greater number of buried thick strata.)

"High viscosity" means that the rock doesn't like to flow at all. In this case it can behave elastically meaning that during a certain time it only responds to the applied extension by imperceptibly (and infinitesimally) changing its shape. During this time, if the applied extensional force ceases (i.e. if by some reason we stop pulling the sandwich) the rock completely recovers its original shape. Eventually, a limit is reached (the so called yield point) and the rock layer breaks apart in several pieces (deforms in a brittle way) - these pieces are called boudins (check Google image to learn the original meaning of this French word).

Fig.2 - Boudins of sandstone interbedded within shales in Almograve beach (Carboniferous of SW Portuguese coast)

What happens in the outer layers?

The "softer", less competent, outer layers display a completely different response (a ductile one) to the same extensional forces; as a consequence of their low viscosity they are prone to flow, i.e. to gradually change their shape along geological time. As a result, instead of breaking into pieces they get thinner, and tend to gradually contour the simultaneously forming boudins.

The result is a boudinaged deformation pattern (see photos).

In some situations the more competent inner layer isn't completely separated into several individual pieces, but instead boudins are separated by short abruptly thinned areas called “necking zones”. Concentration of fractures in these "necks" is common (since they correspond to weaker zones), and they often exhibit abundant quartz veins, tension gashes, etc.

Fig.3 - Boudins of sandstone Almograve beach (Carboniferous of SW Portuguese coast). Note that the length of the individual boudins is proportional to the thickness of the competent layers.

Boudins exhibit sharp edges and well defined geometric shapes, as oppose to more diffuse boundaries and round (barrel shaped) forms, when the viscosity contrast between the individual boudin and the matrix (i.e. the surrounding less competent rock) is extremely abrupt.

Fig.4 - A folded boudinaged layer of Carboniferous sandstone in Almograve beach (SW Portuguese coast). The fold formed before, simultaneous or after the boudinage? What is more likely to have occurred based on what is observed in the photo? (post your justified answer in the comment box below).

This is the case of the highly rotated anphibolite boudins found immersed within lower Paleozoic carbonate rocks (Ossa Morena Zone, SW Iberian Variscan orogen), which I have studied during my PhD a few years ago. We examined the rotation of these small boudins under non-coaxial deformation, and deciphered the relation of this with the generation of non-cylindrical and sheath folds in the layered carbonate matrix (here’s what we have published about it).

Iceland volcanic eruption: short interview with geologist José Madeira (Lisbon University)

2010-04-17T19:15:00.004+01:00

José Madeira is a geologist and a Professor at Lisbon University (Faculty of Science, Geology Department), and a research member of IDL-LATTEX laboratory. A substantial part of his work has been dedicated to the study of the geology of volcanic regions, namely in the Atlantic ocean where he has done significant research in Azores, Madeira and Cape Verde archipelagos.

(left) 1995 Eruption in Fogo Island, Cape Verde archipelago (foto by J. Madeira)

Since the recent Iceland volcanic crises he has been invited for several national (Portuguese) television news channels, to contribute as a specialist to the on-going debate concerning the causes and consequences of the recent Eyjafjallajökull volcanic eruption.

The Lisbon Structural Geologist (LSG) asked Prof. J. Madeira 4 questions:

LSG: Is this a normal phenomenon in this part of the Planet? Why?

JM: Yes. Iceland is a major Hot Spot, coincident with the Mid-Atlantic Ridge, so volcanism is a common phenomenon in the region. There are many active volcanoes and one characteristic of Iceland volcanoes is the occurrence of glaciers on top of the volcanic mountains as a result of the high latitude. This can cause frequent water/magma interaction, resulting in increasing explosivity, and may lead to the formation of jokulhaups (sudden release of huge volumes of water and ash mixture formed by melting of ice by an eruption).

(left) Floating lava baloons at Serreta: 1999 eruption in Terceira Island, Azores archipelago (foto by J. Madeira)

LSG: How long can this type of volcanic eruption last? Do you confirm the possibility of it lasting for months or even years, or is this just nonsense?

JM: No one knows how long an eruption can last once it starts. The best clue is to look at the volcanic history of each specific volcano. After Viking settlement and before this event, Eyjafjöll erupted 3 times: in 920 AD, 1612 or 1613 and 1821. The latter eruption lasted for 13 months. This means that a long duration is possible.

LSG: Is this type of phenomenon important for science? What new things can we learn with it?

JM: Volcanoes will always surprise geologists with unexpected things, so every time we follow an eruption new things are learned. Seeing an eruption is more informative than studying from a textbook.

(left) Faial Island (Azores) ignimbrite (1200BP, foto by J. Madeira)

Lava sample from 1808 Urzelina eruption in St. Jorge Island, Azores(photo by J. Madeira)

LSG: Can identical or similar volcanic eruptions occur in the (Portuguese) islands of Azores and Madeira archipelagos? In your opinion, are we prepared to face them (both from the logistic/social and scientific points of view)?

JM: No doubt about that. Except for the glacial context and interaction, we can expect eruptions to occur in the Azores. Since settlement, in mid 15th century, there is a record of, at least, 26 eruptions. The eruptive styles range from hawaiian/strombolian to plinian, and phreato-magmatic (including surtseyan type littoral eruptions). The dimension of the eruptive clouds of plinian and surtseyan events may also cause disruption of air traffic in Central Atlantic. As to Madeira, which is usually considered as an inactive volcano, there is evidence for Holocene volcanism in the geomorphology and volcano-stratigraphy and one ash deposit has recently been dated to be 6 to 7 thousand years old. Those facts clearly show that it isn’t an extinct volcano but rather a dormant one.

In the Azores there is already a reasonable volcano monitoring infrastructure at the Azores University (seismology, geochemistry, Geodesy, etc.) with a strong link with the regional Civil Protection, but not in Madeira. However, the logistic management of a volcanic crisis in an archipelago of small islands can be very complicated specially if coincident with bad weather conditions which are common in winter.

The LSG acknowledges J. Madeira as the sole author of all the magnificent photos presented in this post, and the author of this blog whishes to publicly expresses his gratitude for J. Madeira’s kind and prompt availability to answer all our questions. Obrigado Zé.

Eyjafjallajökull South Iceland Volcano

2010-04-15T13:43:00.004+01:00

For those friends who wonder what the hell is geology all about (and that keep asking me how can I make a living out of this thing) this has been a revealing week with a major quake in China (Qinghai province) and a sub-glacial eruption in south Iceland.

I am force to postpone a more detail post on both these issues, for I am facing a great deal of work right now, but I leave you some links with the basic information I have bee reading about, concerning the Eyjafjallajökull volcano, which forced the closing of air space in Northern Europe today:

- Beautiful images here and here

-Illustration of volcanic ash dispersion here

- Details and summary on the geological situation here, here and here

- About floods caused by sub-glacial eruptions see here

A brief explanation of what caused the volcano in south Iceland and the Qinghai Chinese earthquake will be made available in a near future post.

Taking a stand against bibliometrics’ orthodoxy

2010-04-13T11:41:00.003+01:00

A colleague of mine has just sent me an Editor’s note from the MSCS Editorial Board concerning the topic of how fundamentalism in bibliometric evaluation is destroying science making (here's the link, I can provide the pdf to those who don’t have access to it).

Here are some quotations from the text that should make us all think:

“If used unwisely, as is increasingly the case, [the Citation Indexes – CIs] discourage people (young ones in particular) right from the outset from daring to think, from exploring new paths: how is it possible to find a job today in the field of science or to get tenure without the inertial consensus of the majority, of the largest research areas, imposed by CIs? So the avalanche effect inhibits or even eliminates variety, which is at the core of culture and science. And the preventive effect against novelty is what we particularly fear.”

“At Ecole Normale Supérieure, in Paris, the departments of Mathematics, of Physics, and of Computer Science have expressed their firm opposition to the increasing use of CIs as a tool for scientific evaluation, or for characterising scientifc laboratories. Note that eight out of the nine Fields Medals obtained in France have been given to former students and/or teachers from this Mathematics department (…). The Physics department counts two Nobel Awards and has an extraordinary scientific history.”

“…we all believe that the use of CIs, as a spreading international phenomenon, is one step further away from a balanced mix between a ‘culture of knowledge’ and a ‘culture of results’ towards a pure culture of results: in the field of science, this is an assured path to having no more results.”

Editors' note: bibliometrics and the curators of orthodoxy

MSCS Editorial Board

Math. Struct. in Comp. Science (2009), vol. 19, pp. 1-4. 2009 Cambridge University Press

DOI: 10.1017/S0000000000000000 Printed in the United Kingdom

In view of this, the image of the Russian Mathematician, Grigory Perelman, who has repeatedly refused the several science awards that he has won, including the Fields Medal (a distinction equivalent to the Nobel Prize in Mathematics), definitely comes to mind. He is an example of an outsider producing enduring, profound, scientific results, which he refused to submit to any ISI magazine.

Grigory Perelman

Don’t get me wrong I struggle every day to publish my work in ISI magazines, and I strongly support the concept of peer revision. It’s the distorting of its original intention, associated to an increasing fundamentalism towards bibliometrics that should make us all think.

Structural Geology: The geo-CSI analogy

2010-04-10T11:34:00.006+01:00

Fig.1 - Geology student at work in Cretaceous limestone to the South of Sintra Batholith (West of Lisbon)

As a geologist what I like the most is to be in the field, to look at rocks, to study all kinds of structures at different scales. I think most geologists share this preference, regardless of being structure geologists, petrologists, sedimentologists, etc.... it all starts in the field, looking at rocks and asking how did this form?

Sometimes, like when we work in Marine Geology, we have to collect data indirectly through geophysical methods (swath bathymetry, reflection/refraction seismics, etc.), but really those are just alternative indirect ways to look at different aspects of rocks, its geometry, its rheology...

I sometimes tell first year students who are just starting their mapping of Mesozoic rocks in the north of Lisbon (part one of Field Geology course) that the job of a structural geologist is a kind of nature CSI:

The crime scene is the outcrop (no matter its scale);

Collecting evidence is absolutely crucial (although the crime scene has probably been messed up for millions of years), and in this case is done by measuring everything with a compass to fully characterize the geometry of all observable structures (in the vast majority of the situations it all comes down to measuring lines and planes);

Fig. 2 - Vertical bedding (Cretaceous limestone) in the northern contact of the Sintra Batholith (West of Lisbon)

Then it is necessary to figure out what is it that the evidence is telling us. This might correspond to interpret the kinematics eventually ascribed to the observed structures, i.e. to guess what changes in position along geological time produced the presently observed geometries. Sometimes it is also possible to say something about the forces (mostly its orientation) that originated these structures;

Fig.3 - Track of dinosaur foot-prints in the same Lower Cretaceus limestone depicted in Fig.2

When this is done for all individual structures, the really hard work (but also the most exciting) starts: the geo-CSI has to try to establish a hypothetical chronological sequence of events leading to the final result he is witnessing. This is done mostly by considering the geometric overprint relationships between structures: if bedding is folded, and if the fold hinge is offset by a fault, which in turn is cut by a dyke intrusion (not affected neither by the fold nor the fault), then the sequence of events is probably (schematically): 1- Horizontal bedding; 2 – Fold; 3 – Fault; 4 – Dyke intrusion.

Very important is to realize that squeezing rocks (that’s really what this is all about instead of murdering people!) mostly involves time, pressure and temperature (fluid circulation also helps). This means that the rocks can be modified as a function of these factors during the deformation they endure, since its minerals change to be in a more stable energetic equilibrium with those conditions. This is the realm of metamorphism and chemical thermodynamics. For geo-CSI structural geologists the critical point is: if we are dealing with high grade metamorphic terranes, to come up with a good hypothesis of succeeding chronological events, it is necessary to combine the recognition of geometric overprint relationships with metamorphic overprint ones (better recognized at microscopic scale). This will eventually lead to chronological reconstructions that are refer to by geo-scientists as PTt (Presure-Temperaure-time) paths. Combined with solid structural data at different scales, these can result in good interpretative models of what is going on.

Fig.4 - Geology students at work near the sub-vertical Cretaceous limestone close to the northern contact of the Sintra Batholith (West of Lisbon). Beautiful load casts can be seen (central-upper part of the photo) showing stratigraphic polarity is normal (older strata to the right)

Finally, as in the case of a Court Law during a murder trial, all the sequence of hypothetic events leading to the dramatic outcome can be staged, to evaluate how robust and well supported by evidence they are. Similarly, the geo interpretative models can also be tested: physical (analogue) modeling combined with numerical modeling is one way of doing it.

Analogue modeling #1

2010-03-28T00:56:00.006Z

Analogue modeling (Fig.1) is a technique in which artificial/laboratory materials are employed to simulate the mechanical behavior of deforming rocks in nature.

Two types of materials are generally used: frictional materials (e.g. sand and other finer powders), to simulate the brittle (Coulomb-Mohr) behavior of upper crustal rocks; and viscous materials (e.g. different types of silicone putties, plasticine, honey, glycerin, etc.) to simulate the ductile behavior of middle crustal rocks or the asthenosphere.

The main limitation of analogue modeling is its incapacity of thoroughly reproducing the thermo-mechanical properties of natural rocks; things like geo-thermal or pressure gradients of the lithosphere for instance, are impossible to directly ascribe to analogue models.

However, the choice of materials with the proper scaled rheological properties can (and often does) provide a very good approximation of the natural example at stake.

The great advantage of analogue modeling is the 3D insight that it easily provides when compared with the difficult that such three dimensional approach still poses in numerical modeling.

Modeling of natural geological processes is thus probably going to be increasingly based on a coupled approach, encompassing both analogue modeling, to get a first more qualitative 3D insight on what’s going on, and a numerical approach to obtain more detailed generalizations.

I will be posting photos of analogue models of wrenching, thrusting and extensional tectonic structures obtained in the LATTEX-IDL Analogue Modeling Lab (Univ. of Lisbon).

The photos on the left (Fig.2) concern wrenching and thrusting. They depict a sand-box analogue model of the morpho-tectonic pattern that characterizes the interference between a dextral strike-slip fault (along the length of the photo), and several thrusts (facing the observer, oblique to the strike-slip fault). Note the several subsidiary structures (like Riedel faults – R’) that are theoretically expected to form in a brittle medium. For comparison an aerial photo of the San Andreas fault is also included (San Andreas Fault in the Carrizo Plain, aerial view from 8500 feet altitude, author and copyright holder Ikluft, photo obtained in Wikipedia here).

Short interview with the author of the “crescent-shaped giant scours” paper

2010-03-22T23:27:00.003Z

Brief foreword:

I feel that blogging makes more sense if I can use it to divulge the work and ideas of young guys dealing with different problems in the realm of Earth Sciences. Plus I think most readers would also be interest to know a little bit more about the person behind the paper (e.g. what are his/hers motivations, why do they like science, what other interests do they have, etc.). So I hereby initiate with João Duarte (the first author of the Gulf of Cadiz scours paper) a series of short (4 question) interviews. As a rule, these will always be about someone who hasn´t yet finished his/hers PhD, and will forcefully follow a preceding post about a paper written by that someone. I´ll try to maintain some kind of periodicity, but I suspect that’s going to be kind of difficult… we’ll see.

Scientific crew of the MATESPRO cruise, posing in front of the NRP D. Carlos I vessel of the Portuguese navy. This was the mission during which the “giant scours” where discovered.

João Duarte (front row, first on the left) is a geologist doing his PhD at University of Lisbon, dealing mostly with the tectonics of the Gulf of Cadiz (Africa-Euroasia plate boundary, SW Iberia/West of Gibraltar Straits). He has just published one paper in which he and his co-authors try to understand the process of formation of kilometric, crescent shaped, giant scours carved in the seafloor at ca. -4000m depth. João is also a blogger, regularly writing in his native Portuguese language about geology and other, mostly science and music-related, subjects. We made him four short questions:

Lisbon Structural Geologist (LSG): As a young researcher working in geosciences what is your main motivation? What moves you as youngster who deals with science?

JD: Well, like a known scientist said before, I would say that I’m just extremely curious. I found on science the most complete, organized and logical body of knowledge. Finding patterns, put them together, discover things is just an amazing game! On other hand, science has this strange capacity of challenging our intuition. For example, for thousands of years people thought that the Earth was flat. It seemed obvious, but it was wrong. I think today, in some aspects, we are still in the same situation. We have just started to unravel some of deepest secrets of our planet and surrounding Universe. I choose geology because I always loved to walk on the field. However, I see science as a whole and the apparent frontiers between different disciplines is, in my opinion, a bit fake. This is particularly truth in marine sciences and tectonics.

LSG: Did you really enjoy your work regarding the “giant scours” of the Gulf of Cadiz? Or did the paper correspond more to the simply important need of publishing the results of your research? From your experience how compatible/incompatible are these two things?

JD: I see the writing as an important part of investigating/understanding processes. We do not really understand something until we are able to explain it to other persons. I always learn a lot about a subject when I have to write about it. On other hand, the best thing to do when you are studding something is to share it with other persons/scientists because they usually make you look to the problem from different perspectives. Science is a kind of Lamarckian process, only works if we transmit our knowledge to the others. Otherwise, your work may turn into a dead end. From this perspective publishing is almost a moral obligation (in the good sense of the concept). And of course it is amazing when you see the result!

LSG: Are you exclusively focused on geology and tectonics or do have other interests in science? Can you name any science books unrelated to Earth Sciences that you might have liked?

JD: As I said before, I see science as whole. I think we cannot really enjoy geology and tectonics if we do not like the other scientific disciplines like maths, physics, chemistry, biology, etc. Geology is the discipline that studies the planet Earth. We cannot take a lot of it if we are only studying rocks (stricto sensu). Rocks are like a book. They can tell you a lot of things about the past (and also the present and future). But to have a good reading on it one must have an open mind on other disciplines. On my free time I love to read about physics and maths, and recently I found myself applying a lot of the knowledge I gained in my work, as was the case of the “giant scours” paper. Following this perspective on science, I would recommend the book “Isaac Asimov's Guide to Earth and Space”, written by one of the most productive genius in science communication.

LSG: As a geologist where on earth would you like to go right now? What place would you elect as your immediate favorite for a geo-visit?

JD: I always felt fascinated with the Scotia Highlands. I never had the opportunity to go there but I hope to visit as soon as I have the time to fully enjoy it.

Crescent-shaped giant scours

2010-03-20T12:26:00.001Z

I have been without blogging for a while now, but I like to think it has been for a good reason. A paper in which I have worked with my PhD student and first author J.Duarte, among other co-workers, for almost a whole semester last year has just come out, after we have dealt with requested moderate revisions by the reviewers.

It concerns some mysterious giant crescent-shaped scours (ca. 5km diameter) that we have discovered in the Gulf of Cadiz sea floor at a depth of about -4000m, and in one of my previous posts about mud-volcanoes I had already mention them.

We propose a model for its origin encompassing the specific hydrodynamics of turbiditic currents at high depths, and the occurrence of hydraulic jumps triggered by blind thrusts.

I’m suspect, but I think of course it is worth reading. Here’s the science direct link, or if you don’t have access to it just send-me an e-mail.

Photos of geological structures - SW Portuguese coast (37º39'31.85''N, 8º48'07.06''W)

2010-03-06T19:16:00.004Z

This is intended to be the first of a series of posts about the great variety of geological structures that it is possible to observe in the beaches of SW Portuguese coast, where late Carboniferous rocks magnificently outcrop.

Most of the depicted structures will be possible to observe life during the field trip of the next GeoMod meeting that is going to be held in Lisbon next September (see all relevant information in here).

A brief description of the observed structures will be provided, and readers are encouraged to comment, add and discuss whatever they might consider relevant in the photos.

Symmetrical folds of of mudstone and sandstone beds.

Detail of a hinge zone in the folded sandstone.

Axial plane cleavage (fan-like geometry) is clearly observed, and a fault offsets the uppermost beds of the hinge zone seen in the photo, getting downwards progressively parallel to the bedding in the right hand limb of the fold.

Axial plane cleavage is geometrically refracted across beds of alternate competence; making a lower angle (almost being transposed) with the bedding in mudstone layers, and a much upright almost orthogonal angle in the more competent sandstone.

8.8M Chilean earthquake

2010-02-27T15:52:00.000Z

A magnitude 8.8 earthquake occurred this morning (3:34 AM local time) in the eastwards dipping subduction zone limiting the Nazca and the South American Tectonic Plates. As usual all the detail information is available here.

The focus of this earthquake was located offshore, ca. 115km to the NNE of Concepcion, the nearest important Chilean town and 82 death casualties were reported so far (actualization in here).

The first images and accounts of destruction are already impressive.

Although this earthquake was of a higher magnitude when compared with the recent Haitian one (M 7.0), a lower number of victims and material destruction is expected. This is probably due to a more “favourable” and less shallow (35km depth) location in this case, when compared to the Haitian catastrophe located at mere 25km from Port au Prince and at 13km depth.

Another difference is that in the Haitian case the earthquake was generated in a strike slip fault (see here a previous post), whereas in the present case, as referred above, it was generated in a subduction zone (see another sketch e.g. in here and didactical explanation here).

Accordingly with BBC a peri-Pacific Tsunami alert was launched (Hawaii, Australia, New Zealand, Central America and Pacific island nations). Latest photos.

Lecture by Thorsten Nagel (University of Bonn)

2010-02-21T22:01:00.003Z

Thorsten Nagel is a geologist and Professor at the University of Bonn, visiting the University of Lisbon (and the analogue modelling lab of LATTEX-IDL) during next week. He is the supervisor of a MSc Student presently doing some work in our analogue modelling lab. In recent years T. Nagel work was focussed on mountain building and high-pressure metamorphism, rifting and extension (opening of the South Atlantic). Last fall he has been on a cruise dedicated to the study of continental breakup in the Woodlark Basin, where he specifically deals with the problematic of detachment faulting (Moresby Seamount Detachment) and rifting mechanics.

All students interested in the above subjects are strongly advised to attend his lecture. Enjoy!

IDL Seminars 2010

2010-02-14T16:43:00.002Z

Lectures on EARTH SYSTEM MODELLING

FACULTY OF SCIENCES | UNIVERSITY OF LISBON

C6 BUILDING | ROOM 6.2.53

THURSDAYS

from 11:00 am to 1:00 pm

During this semester IDL is organizing a set of seemingly tremendously interesting seminars with top specialists on Earth system modelling from several European institutes (ETH, Zurich; IPGP, Paris; IC, London and ENS Lyon).

Attending these seminars is a rare opportunity for all students and Earth-Science researchers to learn about different state of the art subjects with top scientists. Don't miss it!

Next lecture:

February 18: Andrew Jackson (ETH, Zürich)
«Understanding the Earth’s magnetic Field through
observation and theory.»

Death Valley: an ongoing field trip by a geologist in western US

2010-02-14T15:56:00.001Z

The possibilities of internet and blogging never stop to amaze me: here's a blog from a Geology teacher in the western US, who is presently blogging from the Death Valley and posting beautiful photos (apparently there is web access in the region!).

What is this thing shaping nature?

2010-02-07T17:14:00.001Z

I found the (absolutely must-see) video below in here. It is about Radiolarians, but really when I watched it I recognized the same feeling of amazement and fascination that I always experience before any other kind of natural wonder. What is this? How does it works? Why? How small are we before the immensity of nature? And how unique considering we correspond to a portion of matter which has evolved to the point of having had developed (at least some degree of) conscienceness?

VSA

2010-02-07T10:19:00.002Z

Following my previous post on mud volcanoes, an old colleague of mine presently working for BP, sent me this link of a Virtual Seismic Atlas, with magnificent examples of a great variety of different kinds of structures and geological features, imaged through seismics reflection and multi-beam bathymetry. I have to say I really find it extremely interesting and useful.

(Thank you Carlos!).

I some times think about... mud volcanoes!

2010-02-05T20:10:00.003Z

Reading a recent post of Chris Rowan in his excellent blog, remind-me of my (very limited) experience with mud volcanoes. I first got in touch with the concept when examining the Gulf of Cadiz swath bathymetry, where aligned arrays of some of these features exist seemingly tectonically controlled by major faults. Then, also in the Gulf of Cadiz (GC) the study of kilometric crescentic depressions carved in the sea floor at ca. 4000m, called again my attention to these structures since one hypothetical way of explaining these gigantic crescentic features was to assume that they could correspond to collapsed mud volcanoes or similar vent structures (pock-marks).

(Crescent shape features and one possible mud-volcano in GC sea-floor at ca. -4km.)

But to be honest I was not particularly impressed until I saw some of these features onshore, in the foreland base of the Northern Apennines, as illustrated in the pictures below. Venting out, warm muddy fluids were permanently bubbling in the mouth of these metric-scale structures, which fed my imagination to consider what happens in the GC sea-floor with kilometric structures of the same type.

(metric scale onshore mud-volcanoes in the foreland of the Northern Appenines)

Geology with the sole of your boots

2010-01-26T22:24:00.007Z

In the call for abstracts of the session: “Crustal-scale processes: Insights from analogue and numerical modeling” of the next EGU meeting, Guido Schreurs (University of Bern) and Susanne Buiter (Geological Survey of Norway) perfectly summarize what I think is the relative importance of analogue and numerical modeling for Earth Sciences today: “Analogue and numerical modelling techniques are widely applied to simulate geological processes (...). The methods are partly overlapping and partly of a complementary nature: Analogue models have traditionally been strong in visualizing the mechanical behavior of processes in 3D, but are still limited in their ability to quantify observables or use more complicated material rheologies. These are better achieved by using numerical models, which are often only 2D but whose 3D resolution has improved in recent years.” I totally subscribe the view about the complementary nature of both - analogue and numerical - instrumental approaches, and stress the fact that indeed we are talking about instruments, pointless in the absence of geological data (based on whatever kind of field work).

The old saying “Geology is mostly done with the sole of your boots!” always pops into my mind, no matter how sophisticated my boots might be, i.e. even when I am interpreting seismic profiles, or rotating multi-beam swath bathymetry images using Fledermaus.

PS - The guys in the photo are looking at the Triassic-Carboniferous unconformity that appears in the this blog "front page". I guaranty it is a tremendous sensation! So much so that Shakespeare comes to mind: "We few, we happy few, we band of brothers" (Henry V)

In September 2010 Lisbon is the place to be

2010-01-26T19:11:00.001Z

You mustn't miss GeoMod2010 meeting! Here is your excelent excuse to come to Lisbon next september:

Click on the image to do your pre-registration

"2010 in Lisbon, Portugal. The main objectives are to present the latest results of analogue, analytical and numerical modelling of the main geological processes currently under investigation, and to set new problems and discuss perspectives and strategic prospective. GeoMod will also pay attention to benchmarking within the same method, and among the different methods used in modelling in Geosciences." From Geomod 2010 official site

In a symmetric version of the same tectonic scenario...

2010-01-16T19:32:00.002Z

... a 5.6M earthquake just hit Carupano about 300km East of Caracas, Venunzuela. Apparently, the seismogenic source is one of the right-lateral strike-slip faults that accomodates the ongoing eastwards movement of the Carrabean plate. A symmetric version of the same scenario that originated the recent Haitian catastrophe.

Haitian devastating quake: Magnitude 7.0, 15km SW of Port-au-Prince

2010-01-13T12:22:00.011Z

BBC talks about hundreds of casualties, people injured bleeding in the streets, no electricity, no telephone, no help in the hours following the main shock. This was clearly a devastating earthquake, even more since it hit one of the poorest countries in the world. Last month a magnitude 6 earthquake was felt here in Lisbon, its epicenter was more than 250km away and its depth about 31km. Still, it frightened a lot of people, including my self. Now imagine a magnitude 7.0, at a shallow depth, only 15km away (keep in mind that the Richter magnitude scale is logarithmic, i.e. an increase of one degree corresponds to a shaking amplitude 10 times larger!).

The earthquake occurred in a left-lateral strike-slip fault, functioning as a northern transference fault of the frontal subduction zone, which accommodates the ongoing convergence between the Caribbean Plate and the North America Plate

source of Fig.

PS - I´ve just found this excellent post about the general tectonic setting in which the quake occurred.

Does any one knows what this might be?

2010-01-12T11:07:00.003Z

These photos are from Zavial Beach (37 02' 44.53''N, 8 52'07.25''W) in South Portuguese coast. We can observe a "structure" that initially seems made by man: thin fence-like horizontal and vertical walls bound coarse clastic convoluted material (no primary or otherwise structures are observed inside). So we thought it could be a kind of an ancient anthropomorphic oven (help from possible Anthropologists readers is required please!)

However, outside (to the right in the pictures) bedding seems to be folded - dragged - upwards as a result of (liquefied?) material escape in the same direction; seemingly as in the case of sedimentary clastic dyke like structures.

Any opinions on what this might be? Does anyone knows any similar features?

The forgoten role of a certain kind of stupidity

2010-01-02T17:20:00.000Z

A friend who is about to finish her PhD in Univ. Lisbon sent me an e-mail with this text attached. A few days later I also received it from my PhD student JD. I guess the subject is popular among hard working researchers.The question seems to be: how important is it to feel stupid in a certain way while working in science? Could the answer be: If you don't feel stupid at all then... there must be something wrong with your research?

(fell free to send me your views on this)

Will we ever inhabit lava tubes in the Moon?

2010-01-02T16:39:00.001Z

"NASA is reportedly working on plans to return to the moon by 2020 and to set up a temporary lunar colony by 2025 as part of the Constellation Program." And guess where humans will probably live...

Could major quakes be aftershocks?

2010-01-02T16:35:00.000Z

I didn't have a chance yet to take a look at the actual paper but this seems really interesting.

Merry Christmas everybody: to all of you that love our beautiful planet, and who are lucky enough to make a living out of trying to understand it!

2009-12-23T20:03:00.006Z

"...So happy Christmas I love you baby I can see a better time When all our dreams come true"!

17 December 2009 Earthquake

2009-12-22T01:15:00.002Z

Last Thursday 17, at 1:37 AM I was at home watching television (I live nearby Tagus River in East Lisbon, in the 3rd floor of a modern building) when all of a sudden I felt the building shaking! I understood immediately what was happening and rushed to put on my shoes, to grab my three children (which were completely asleep and realized nothing) and exit . When I had finished with the first shoe, the earthquake was over.

It turn out to be a magnitude 6 earthquake located near the St. Vicent Canyon, offshore SW Portugal at ~31km depth (data from the Portuguese "Instituto de Meteorologia"), and although at a distance more than 250km away I clearly felt it! As I found out the following morning a lot of people did, and in my case it was enough to question my self, during short period of time it lasted (~10 seconds?), if what I was feeling could be in fact only the beginning of something worst.

I should know better, I am presently doing some analogue modelling work of some important active faults in that same region (see Fig. below)!

In future posts I will publish three short interviews (4/5 short questions) to Earth scientists (geologists and geophysicists) who have long been studying the tectonic evolution and seismicity of the Gulf of Cadiz region.

Speaking of lists...

2009-12-21T23:52:00.002Z

This one is not so bad either.

"The List"

2009-12-21T23:27:00.001Z

How many of these geological wonders have you faced already? Well hurry up! You live in a time when is actually possible to see them all. Sure your grandfather couldn't say the same!

If you have already seen some, I invite you to share your experience here in the LSG with our readers. Send-me your account!

On the right side of the Atlantic?

2009-12-19T00:03:00.007Z

For someone who works on a Gulf on the opposite side of the Atlântic (Gulf of Cadiz) it is interesting to learn that in the opposing Gulf there is also still a lot to be discovered...

It seems that to get funding what you guys need is a major earthquake in your Gulf...

Arizona Paleo-Piranha movie?!

2009-12-18T23:32:00.003Z

From the blog of the state geologist of Arizona comes the stunning news: a new film is being prepared, staring Richard Dreyfus (well known from his acting work in "Close Encounters" and "Shark"), and Scott Adams who plays a diving geologist dealing with horrific prehistoric Piranhas in the bottom of a lake!

Why is it that the mixtures between geology and movies - from dinosaurs to volcanoes - always "taste" like this?
Mercy please!

Why do we love beer?

2009-12-18T23:11:00.001Z

I think everybody does. We just fight harder for it... hence we get it in geo-meetings!
Here's confirmation from the ongoing AGU meeting in SF

Geomod 2010 meeting: pre-registration is now open

2009-11-30T16:20:00.005Z

From Geomod 2010 official site

Lisbon and Earth Sciences: the catastrophic connection

2009-11-30T16:05:00.006Z

In November the 1st 1755 a major earthquake (estimated magnitude of M= 8.5 to 8.7), followed by a devastating tsunami and several lethal fires of huge proportions, destroyed almost completely the capital of the fervent catholic Portuguese Empire; the city wherefrom more than 250 years later I write these lines: Lisbon.

Images from the Kozak Collection, Earthquake Engineering Research Center (fair use policy)

This happened in All Saint’s Day, in the morning, killing a great number of devoted people inside the congested churches and, ironically, leaving intact the street then known as the main location for the “oldest business on earth”.

It was no ordinary catastrophe. The earthquake was felt through all over Europe (as far as Finland), and the tsunami was reported to have reached several peri-Atlantic margins far away such as southern Brazil, the Caribbean and Scotland.

In the Europe of the XVIII^th century the impact of the abrupt destruction of one of the more important European cities at the time was tremendous. Immanuel Kant in 1756, one year only after the disaster, wrote about explosions in huge subterranean caves linking the Alps to the western European coast in one of the first attempts to explain the phenomena, while religious leaders hesitated between God and the devil in their own interpretation exercise of what had happened.

Portuguese historians compare the effect of the Great Lisbon Earthquake in the society of the time with the recent attacks on the twin towers, or with the Sumatra earthquake and tsunami of December 26, 2004.

Unlike the Sumatra earthquake however, until recent years, no major correspondent geological structures were known in the Portuguese offshore to account for the source of such a large earthquake and tsunami.

Main bathymetry features of the Gulf of Cadiz area:offshore SW Iberia, Euroasia-Africa plate boundary (Back ground image from Google Earth).

It was only in the beginning of the previous decade that a massive new amount of data (bathymetry, seismic reflection and refraction, side-scan sonar, etc.) has been acquired offshore SW Iberia, in the so called Gulf of Cadiz (Euroasia-Africa plate boundary), and since then, several major tectonic structures (mainly thrusts and strike-slip faults) have been discovered.

The so called Gorringe Bank for instance is a submarine mountain equivalent to the “Mont Blanc” in the Alps, located offshore the southwestern tip of Portugal: its top is at merely 25m beneath the water surface, whereas its base is at around 5km depth!

Further reading and related internet sites:

http://nisee.berkeley.edu/lisbon/

http://www.fordham.edu/halsall/mod/1755lisbonquake.html

http://nearest.bo.ismar.cnr.it/

http://www.mundiconvenius.pt/2005/lisbon1755/default.htm

Students' protest in University of California

2009-11-22T13:41:00.003Z

They call it tuition. It´s a fee that has to by paid by students, and that has been abruptly increased (32%) by the university. The last sentence reads: "Students eligible for financial aid and whose families make less than $70,000 will have their tuition covered...". I wonder if this is enough to avoid good students dropping their high education efforts because they simple cannot pay. The governments worldwide hesitated very little (or nothing at all) to pay for the gross financial errors and crimes that sunk the economy. What about education, do they think it does not count?

Why in English? Why not in Portuguese?

2009-11-21T01:19:00.000Z

Because since I will write mostly about (earth) sciences, writing this blog in Portuguese would in fact make absolutely no sense, and would merely be impeditive of a broader audience to read whatever will be posted here. Science has no frontiers, neither has Geology. Like it or not (myself I don’t mind particularly), the nowadays international language is English, a kind of modern times Latin. That is the language we use to write and read science papers, and the language we use when we go to a science conference anywhere in the world. That’s why.