The Way of the Geophysicist.

I'm back

blog@dramsch.net (Jesper Soeren Dramsch) — Thu, 13 Jun 2013 09:52:03 +0200

It has been almost two months now that I posted something on this blog.
I'm sorry, life got the best of me for a bit. But I'm back with a couple nice posts about a phenomenon we call the seismic ghost and other fascinating things surrounding geophysics and science. But let's start with a little fun content:

Geology wins!

I am always delighted when some new gadget gets compared to a rock. I like rocks.
And again we have a clear winner.

via Eatliver.com

How geologists view the world.

blog@dramsch.net (Jesper Soeren Dramsch) — Thu, 11 Apr 2013 18:26:15 +0200

Just a quick reminder, how geologists view the world:

via tastefully offensive

Improve your programming; be a better geophysicist

blog@dramsch.net (Jesper Soeren Dramsch) — Sat, 30 Mar 2013 14:01:00 +0100

My personal experience with geophysics is that it's very heavy-sided towards programming.
For me this is great. I have been quite the nerd in my childhood and learned some very basic C programming on my first computer. However, I can understand if you didn't have that kind of head start. A lot of my mates in university didn't and struggled quite a bit to get some assignments done because that knowledge in programming wasn't already present. Unfortunately, our university doesn't really have a lot of courses about programming basics or alternatively they're in Fortran¹

Learn how to program

At one point in your student career, programming will come in handy. A lot of monotonous tasks can be automated by programming, so why not give it a try. Matt Hall over at Agile* has written a piece about why you should learn programming.
Seriously, teach yourself how to get those pieces of code to work. It's fun to play around, break and again fix your code. And there are various resources you can get started.

If you don't know which language to pick, I would recommend Python to start with. It's easy and focuses on readability, so you will have a big advantage when searching for errors in the code. In the end it will be best if you know different styles of programming languages, but as far as I'm concerned, I'm a geophysicist: I put the idea of the physical model into code and a software engineer will be much better translating into a language that is fast than Python. But if you're ambitious don't bother to learn something like C or C++ as well.

Getting serious

Once you get over the "just playing around phase" and actually have an assignment to do, you need to get some structure into your ideas. One of my assignments in university was coding a cooling model of a magma chamber using partial differential equations including source points. If you don't have a structure for this kind of programming laid out, you will probably go mad. Yeah, or get a Nobel prize once you free up the resources you previously needed for structuring it in your head.
You can do this with a mind map or just some pseudo code on paper, just get creative. This will be your guide through the coding jungle. It's easy to lose sight of the final problem so this road-map is your friend in structuring your creative process.

A roadmap for a simple migration routine

Continue reading "Improve your programming; be a better geophysicist"

The letter "J" [It's okay to be smart]

blog@dramsch.net (Jesper Soeren Dramsch) — Thu, 28 Mar 2013 06:26:30 +0100

Joe Hanson over at It's ok to be smart obviously has the same problem I do...

Why isn’t there an amino acid or nucleotide or element with the one-letter symbol “J”?

Because I can never write out my name in anything science and that’s just not fair.

Maximizing your Geo-knowledge in minimum time!

blog@dramsch.net (Jesper Soeren Dramsch) — Thu, 14 Mar 2013 16:40:00 +0100

Publish or perish!

This is often the case in academia. The knowledge base is ever growing and keeping up can be quite a hassle.
Checking all the different websites for valuable information or the newest papers can be very time consuming. Fortunately, the early internet has brought forward RSS. It's an acronym for Real Simple Syndication, so basically you can get all the information from different websites really simple.

I've been meaning to write this article for quite a while and I wanted to recommend the Google Service - Google Reader. However, today the big G announced that they would discontinue the service². Everyone can pack their so called feeds of websites and go somewhere else. So why still write about it? All hope is gone! Well not really and even if you have never been into RSS feeds before, keep on reading this will change your view of the internet!

My first reaction after seeing the anouncement, I tried to install a RSS Reader on my own webspace. That failed miserably so I started looking around for alternatives and they delivered. There is a very extensive list on Wikipedia, but I almost died from information overload while browsing that thing. So let me sum up what I got out of it:
You can chose between the usual desktop program or cloud-based services like Google Reader.
For me this choice was pretty easy, I work on three different computers and have a smartphone, I need something that syncs all across those devices without problems. A desktop solution wasn't an option for me. When looking for cloud-based RSS services, I found that two stuck out.

There is Newsblur, which looks pretty much like Google Reader and will be fine.

However there was another option called Feedly.

It's more of a magazine style feed reader and I like the style very much. Especially for News feeds this can be a nice addition. They reacted very quick to Google Reader closing down and provided a guide for new ex-Google users that will show you through the import of your feeds. It's a two-click process then you're done! Just allow them to connect to Reader and that's it all your feeds are there.
For the true minimalists that liked the Reader design a lot, they can just use the "Tile View" that will give you the same plain Google Reader interface³.

I used this little switch to Feedly to clean up my feeds and I would very much like to share some of them with you.
Some other bloggers published their lists of publications they follow⁴ ⁵ ⁶ ⁷. I will present some highlights from the list, however I have taken the freedom to compile files that you can simply import in your favorite reader. They're called OPML-Files and if you're not sure how to import them into your reader you can google it. I have uploaded five different files that include:

Continue reading "Maximizing your Geo-knowledge in minimum time!"

An Introduction to productivity

blog@dramsch.net (Jesper Soeren Dramsch) — Wed, 13 Mar 2013 06:16:58 +0100

This part of The Way of the Geophysicist is brand new but none the less an important part.

If you ever felt yourself struffling for productivity or asked yourself why you couldn't just be more disciplined, this will be exactly the section for you.
I myself have been struggling with myself for quite some time.
I have questioned my willpower, discipline, productivity or sometimes even sanity for that matter.

"Why can't I just do the work?"

For me this was a pretty easy answer, I wanted to much and I wanted it yesterday. Within the last years I have learned some important lessons and I would very much like to share them with you. The quote that gave name to this section is inspirational to me:

Motivation is what gets you started,
Habit is what keeps you going.

There's no discipline or willpower in that quote and there's a good reason for it.
Luckily the authors over at ASAPScience have compiled a wonderful explanation of productivity. I'll leave you with this for now, this will give you a head start.

Moh's Scale updated

blog@dramsch.net (Jesper Soeren Dramsch) — Thu, 21 Feb 2013 06:51:13 +0100

When it comes to minerals, they have certain properties. One property is the hardness. Back in the day German mineralogist Friedrich Mohs had the idea to introduce a scale, where you basically take two minerals and have a look which one can put scratches into the other. This scale has ten levels from extremely soft to hard like a diamond, however we might consider to update this scale especially when we consider that Thor's Hammer obvisously looks like this:

Anyone who ever owned a Nokia should be able to relate to this.

via IFLS

Nevertheless, if you really do want to see a material that is harder than diamond, read up on these awesome aggregated diamond nanorods!

In soviet russia...

blog@dramsch.net (Jesper Soeren Dramsch) — Sat, 16 Feb 2013 13:34:41 +0100

A short introduction into seismics

blog@dramsch.net (Jesper Soeren Dramsch) — Sat, 16 Feb 2013 13:07:00 +0100

The basic concept of seismic is pretty easy.
We send sound into the ground and listen what comes back to the surface. There are a lot of sources we can use to make this sound. A very basic but effective approach is to use a sledgehammer and bang it on a steel cap on the ground. This works well to get some acoustic waves into the top layers of the subsurface, but there are even some ways to get images from the boundary between Earth's crust and the mantle. We need more sophisticated ways that get this amount of energy into the ground.

The easiest way to do this is to bust out the big guns and hammer more energy into the ground. We could call this the mythbusters approach.

But once we start to use a charge of explosives that is big enough something like this might happen.

‘Sir George Grey Special Collections, Auckland Libraries’, 7-A16471

We also have to consider that using explosives isn't exactly the green way to go. The environment will get damaged and it will obviously be harder to justify the use of explosives. However, if we can't use brute force there is another way to go. Instead of sending a big amount of energy into the ground at once we can send less energy over a sustained time.
This is a method called Vibroseis. A hydraulic system mounted on a truck sends vibrations into the ground. This vibration will usually last twelve seconds and change in frequency. I have attached a video of one of these trucks below. It's not too spectacular but don't underestimate that truck it weighs around 30 tons.

How does this give us any information about the subsurface?

All the time I have been talking about sound in the subsurface, but when we look at sound it is basically an acoustic wave. This wave travels through the ground just like our favorite piece of music travels from the speaker to our eardrum. The air that transports the sound of music is fairly homogenous, however the ground beneath us had 4.54 ± 0.05 billion years to form and a doesn't mix quite as well as air. There is quite a lot of history hidden under our feet. Over time the depositional patterns change and additionally we have processes like tectonics that cause unconformities in the subsurface. When an acoustic wave encounters a change in the subsurface part of it will be reflected and another part will be transmitted. The part that was transmitted will be reflected at another change in the subsurface and so on. On the surface we record the reflected waves with something called geophone and through thorough analysis, we may obtain an image of the subsurface. Just take a look at the picture of the grand canyon. You can easily identify different layers of rock just like seismics would in the subsurface.

CC-BY Tobias Alt

Marine seismics

This works very well on land, but 71% of the Earth are covered by water and those trucks don't swim too well.
Fortunately water can transport acoustic waves as well, so we just need to find a suitable source to send sound into the water that travels down into the subsurface. This works quite well with something we call airgun. It injects a bubble of air into the water that collapses. This collapse will create the acoustic wave we need.
Listening for that wave is the next thing we have to solve. Ships create a lot of vibration, so we have to record the acoustic waves somewhere else. The listening devices are stored in something we call streamer that gets dragged behind the ship.

Seismics is pretty easy, when we boil it down to its core.
You send sound into the ground with some sort of source and then have devices that will record the reflected waves back at the surface.

Beasties of fur and of feather

blog@dramsch.net (Jesper Soeren Dramsch) — Tue, 22 Jan 2013 08:00:07 +0100

Our world long ago with lands joined together
when first appeared beasties of fur and of feather.

Artistic view on the life in the triassic period by Richard Morden. Get it here!
(All copyright belongs to him!)

This artistic map shows the supercontinent Pangaea and the Tethys ocean.
It's a surprisingly accurate depiction where the landmasses of today were in the triassic period.

Pangaea 250 to 200 million years ago

Pangaea resulted from the collision of the two major continents Gondwana and Laurussia, surrounded by the great panthalassic ocean.
We're looking at a time after the Perm-Triassic extinction. It took another 30 million years¹¹ for life to redevelop into it's beautiful diverse complexity and it was the start of an era. The dinosaurs inhabited Earth. They're not quite drawn to scale but that's artistic freedom. We can find Ichthyosaurus South-East of the lettering Tethys Ocean, which was a highly succesful marine predator. Down in "Antarctica" South of Pangaea you can find a shark-like lifeform. In case you didn't know, yes sharks are some animal that happens to be around a little longer.¹²
On land we can find the first known flying reptile, the pterosaurs, just between Europe and North America. The other species on two or four legs resemble quite a few images I found of Proterosuchus, Cynognathus, Coelophysis and the famous Plateosaurus. However, I'm not an expert here and someone else would probably be better at pointing out the different species that resemble those drawings.

But there is more!

When we look outside of the map we find the header with two reptile heads. Our scaly friend on the left would be the beasty of fur, whereas the head on the right is the beasty of feather. For the old folks that haven't played with dinosaurs for a while, yes dinosaurs most likely had feathers.¹³

xkcd - feathers CC-BY-NC 2.5

And on the bottom we see a couple of plants. On the left those resemble the first "palm ferns" (Cycads) which depict the rise of gymnosperms in the Trias and there are even some Pleuromeia. On the left we see different species that can be placed in the marine flora.

This map is incredibly detailed and a wonderful artistic interpretation of the state of science on the Triassic period.
You can get it in print from Richard Morden on redbubble.

I will go and read up on the PLoS collection on paleontology you can follow me or have a look over to itsokaytobesmart.com where I found this piece of art.

Dangerous cargo and magnetic prospection

blog@dramsch.net (Jesper Soeren Dramsch) — Sun, 20 Jan 2013 18:27:14 +0100

This week a boat in Hamburg was carrying dangerous cargo.
It was an unexploded grenade that had been found on a building site. Now it might seem weird that this kind of cargo is being transported on a boat on the largest lake in Hamburg, but a time fuse made it impossible to defuse the bomb. The safest way to handle this, was to carry the grenade out into deeper water and explode it under controlled circumstances.

This is quite a problem in Hamburg and Germany in general, when there is a building site, it's quite common to find blind shells from WWII. It can be quite risky to just start building somewhere without knowing the subsurface.
So geophysics knows a solution to this problem¹⁴. Ironically, this solution was developed for the purposes of war.
When submarines were in vogue for sea battles, people obviously wanted some way to find those sneaky machines. Since they're built of metal there was an easy way to detect them using some form of magnetic anomaly detector. These could be used from an airplane to search the seas for a threat.

Grenades, bombs and submarines have one very important thing in common. They're made from metal.
When searching for blind shells we could just use these planes that were used before, right?
Unfortunately we cannot. Submarines are a little bigger than blind shells. Another "problem" is that geophysicists like to be paid for their work, so a lot of building sites use an "on-the-fly prospection", which basically means they start digging and have a look for unwanted surprises, instead of doing a proper inspection beforehand. This can be quite expensive when the entire building site has to be evacuated but many builders are willing to take the risk. However, some people take the precaution and this is how a magnetic measurements work.

We all know the comparison of the Earth's magnetic field to one of these old magnets with two poles. However, the global magnetic field underlies some variations over time. Every five years a global model is issued to account for the newest measurements. This is called the International Geomagnetic Reference Field (IGRF)¹⁵

International geomagnetic reference field

When a magnetic measurement differs from this IGRF we call this an anomaly, which could be an indicator for metal in the subsurface. But how do we even take this measurement?
Continue reading "Dangerous cargo and magnetic prospection"

How to survive a temporary long-distance relationship.

blog@dramsch.net (Jesper Soeren Dramsch) — Thu, 10 Jan 2013 08:00:00 +0100

Are you going abroad and your loved one has other obligations?
Well here are some ideas to cope with that situation.

I live in a 2.25 year relationship and 6 months of this time I have spent in other countries. One year into the relationship I went to Oslo, Norway to have an internship at Fugro Seismic Imaging and another year later I visited London to work with Western Geco / Schlumberger.
This hasn't always been easy, I admit.

Two months seemed like a long time and it was, but you can make the best of it.
Then four months seemed like a time our relationship would never survive, but we are closer than ever and happily ever after.
So what's the trick of a temporary long-distance relationship?

First off: Keep it temporary!

By all means, I am a firm believer that long-distance relationships do not work. If you're separated for a time that is endless, you will probably not make it. Knowing that I will be back in a fixed amount of time, saved me a good amount of nerves. I knew exactly, which flight I would take even before I was in London or Oslo to come back to Hamburg.

Communicate!

It will be an entire new level of communication you have to do when you can only talk to be close. It will take a lot of effort but it is worth it.

Use technology!

It's so easy to make a video call for free these days. Do it. Make it a ritual even. When I woke up at 6 in the morning first thing I would do is fire up the computer and call home for half an hour. This way we could have breakfast together and start our day. Personally I gained experience with two different providers and three services. Google has implemented two different approaches for video chats. There is the commonly known Google Hangout, this probably isn't as suitable for you. The base functionality of hangouts are group chats and there is just too much stuff going on for a normal two-person chat. Then there is a two-party video chat implementation in the normal Google Talk chat. This works quite well and doesn't need big setups. However, we had some feedback loops and noise canceling isn't quite good. Sometimes you had the feeling that the chat had a feedback loop with itself. Also the chat is implemented in a web service and can be called over Google Plus or Google Mail, which is convenient at first but it happened more than once that we closed GMail and the chat was accidentally gone.
My personal favorite is the standalone program Skype. The sound quality is very good if both parties use decent hardware and we had almost no feedback or background noise. The video quality gets adjusted to your bandwidth, so it is hard to compare but when you don't do anything but chat, the quality is magnificent. One of the main benefits is that there is almost no way to accidentally close Skype. This can be annoying at other points of time, when you want to close Skype but then again, yeah who cares. Also one thing we found very convenient is a little gadget Skype implemented. You do not have to have the window open to see the video chat. When the main Skype window isn't active, a small window pops up with the video chat that stays on top of almost anything. This way you can play games together and share the experience or maybe watch a movie over Lovefilm - you imagine the possibilities. However, you might want to consider that Skype is a closed source system and the Google video chat goes through Google services as well. Skype has (had) some security issues and some serious privacy issues¹⁸. Google's services are mainly open source but you still chat through a system run by one of the biggest data mining corporations, just be careful what you talk about. When you go more low-level, maybe use part of your lunch break for a quick text chat to talk about your day. The chat integrated into the Google services works on most company networks, because they will not block Google. Facebook chat might be blocked on many work sites and I am not a big fan of sharing sensitive information through a service that is known to sell anything, they can get a grip on – but that's your choice.

Invest in your relationship!

Investing in your relationship is quite a metaphor in most cases. This time I mean it literally. Put some money aside and invest in your relationship.
We visited each other regularly, which made the time less "long distance". Booking a cheap flight well ahead of time will save you some serious money and maybe your relationship. It isn't always that easy. You are probably restricted to weekend flights and this will increase the price significantly, compared to a flight in the middle of the week. Head over to Swoodoo and compare prices. Also check if it's cheaper for you to fly back home or for your loved one to come visit you. I had some magnificent times in Oslo and London, when my darling visited me. We did some trips to the most beautiful places around and those will be good memories. Reviewing this text I realized that there are probably some people out there that have to live in different places that can be reached by train. Don't get me wrong and please don't make that assumption yourself, visiting by train is just as hard as flying, maybe even harder. In case of flying you have different opportunities and price comparison sites, Hamburg-London took 1.25 hours one way, which is absolutely ok and gives you some quiet time. Taking the train can be much harder, there isn't a lot of competition, the seats aren't as comfortable and a lot of people are running around disturbing your quiet. The most important thing though, although you're physically much closer, the time and effort to take the train are basically the same. Appreciate the visit just as much as a flight arriving with your darling. Always collect them from the airport/train station, it's the best feeling of a warm welcome.
You could also send some flowers for little money. Make your loved one happy with just 10 to 20 Moneys¹⁹. I can only tell about my experience in Germany, but that will be transferable to possibly anywhere. There are two big differences in flower delivery systems. There are deliveries like Blume2000 that have a couple central flower preparation centers and ship the flowers with a normal parcel service. Some reviews state that the flowers arrived wilted, however Blume2000 has a guarantee that the flowers stay nice and fresh for a week or two. Personally I never had problems with this service and it is fairly cost effective. Once I had a problem with the parcel service, being lazy and not delivering the flowers although my darling was at home the entire day, stating they could not find her. One call to Blume2000 solved the problem and also had the side effect that we get every parcel delivered without problems now. One main advantage is that every bouquet looks like the picture on the website.
The other system was introduced by Fleurop. They have collaborations with local florists all over the world and distribute the orders accordingly. Personally, I think this is a much nicer way to go. Although there is a slight difference in price, you strengthen local florists and have a bouquet of very fresh flowers delivered. Another difference is that the pictures on the Fleurop website are only ideas or inspirations how those flowers might look like. Once I ordered some flowers in the other end of the world, Australia, which was a very interesting experience. This bouquet wasn't like the picture at all. The local flora wouldn't have made it possible to include the same flowers as in Germany, but it was a very nice gift and the bouquet was very individual and absolutely stunning. Often you can even include some stuff "women like". I am deeply sorry for the stereotype – when I click through the collection of additions, my perception is that some guy sat down and tried to imagine the most cliche gifts, but I guess some Belgian Chocolates won't hurt. So what excuse do you have to forget Valentine's day while being abroad?

Share and keep some hobbies!

This will seem odd, because how can you still share a hobby when you're several kilometers apart?
When you are living long-distance and you phone regularly you will soon realize a discrepancy between the time you want to talk and the things you can talk about. I was working full-time in Oslo and didn't have a lot to talk about but my need for a close relationship was just the same. Sometimes we would run out of things to talk about. Yes the first couple weeks are exciting and you have a lot to tell, don't worry about those weeks they're easy. But you can take some preparations for the time after.
My darling and I used to play board games a lot and it just so happened that I was pointed to a web page where we could play some of our favorite board games over the internet while being on the computer. This part is even easier if you're a couple that plays computer games together, you figure that one out yourself. Also you can still "go to the movies together", when you consult a streaming service for movies and watch your favorite movie together.
This part gets a bit tricky, when you used to do non-computer related hobbies together. Let's assume you went rock climbing together, sharing this immediately might be a bit too much. But you can take pictures and share the experience. You will have something to talk about on the phone later on. But you need some tact in this situation, remember you did this together before and now you substituted your darling for another climbing partner. Make sure that he/she can engage in an activity too. It will not always be easy but it will be a possible solution. Technology has made sharing very easy, a whole industry is built around sharing your meal with a sepia-filter²⁰ so why not make sharing private again?

Have something to look forward to!

When I visited back home, we had something planned. Be it a nice dinner or some sort of party, we had something to look forward to other than just the pure presence of the partner. This was also something to talk about and to share. Make your visit worthwhile. The weekends we spent together weren't as relaxing as I would have liked them to be. You have to get used to each other after a period of absence, you have a lot of things planned, you want to spend quality time. Go figure. However, those are weekends you feel alive. You'll need the Monday at work to recover a little, and have an extra coffee, but the energy invested in that weekend is energy invested in your relationship and your health of mind.

Build rituals!

I mentioned it before when I told you to use technology but this is something I want to stress.
Build rituals with each other. Waking up in the morning and calling home, was one of the best ideas we had. It made a huge difference to start the morning together. We had to take compromises to make it every time, while I had to wake up at 6 am, my darling sometimes had to run to catch the train because we took too long to say goodbye and send the best wishes for the day ahead. We also called in the evening but this was a bit more flexible. When either one of us had something planned with friends or colleagues, we skipped the evening call and made up for it the coming evening.
Another wonderful ritual was built around me visiting home. We have a nice restaurant two train stations from home that has a Happy Hour right around the time my plane would land. We would just go there for the evening I arrived and have dinner and some cocktails together. This was a great measure to get used to each other again.

Get used to each other!

Now this is something that you will probably start to understand after the first two weeks of absence. You are living two separate lives and although you are doing your very best to stay close and still maintain that relationship, you are going to alienate a little bit. I think I have to elaborate on this, because it might make it seem like all those things stated before are worth nothing, but think about it this way: The less you do for your relationship, the more you will alienate, while the maximum alienation is a break-up. If you are a person that can transition from long-distance to short-distance within a blink of an eye, I salute you. I can't and I am quite good at rationalizing things which would make it easier on my part. You will get used to each other within the first couple of hours and it will get a tad easier to transition when you have gained some experience in this kind of change. But you will always need some time and you should take that kind of time.

Temporary long-distance relationships are manageable, but they are a lot of work.
Give it your best shot if it's worth your relationship.

My darling has endured six month with me living abroad and we both weren't sure we could do it, but in the end I would say we both grew from the experience and we are closer than ever.

Happy New Year!

blog@dramsch.net (Jesper Soeren Dramsch) — Thu, 03 Jan 2013 14:25:00 +0100

A new year starts and suddenly a lot of people are concerned about their gravitational attraction to the Earth.
In January new subscriptions to the gym spike compared to every other month. Weight watchers and a lot of the other programs for weight reduction invest in every commercial break on TV.

Gravity is a very well-known physical process, in a sense that everyone knows gravity exists. Some old indian guys even wrote about it before Aristotle. However, we have a couple of problems describing gravity. On Earth, we stand on a huge ball of mass. So the first descriptions of a gravitational force were pretty simple that an object will always fall down towards Earth.
This of course is not wrong, yet it took quite some time to figure out that gravity does not only have things fall down but in general have objects attract each other proportional to their mass. So in principal when we look at the Earth as a gravitational object, the Earth does not only attract us but we also attract Earth - At least a tiny bit. We trust a mechanical device to measure this attraction and tell us our weight.
This weight would be the same on every place of the world, right?
No. I'm not talking about kilogram, pound or stone here, it's something quite different. When we measure ourselves on a scale, this scale measures the attraction of the mass below us to the mass we put on the scale, our body weight. If the Earth was a homogeneous ball that had the same density and material at every single place in this ball, the weight would not be different if we travelled around with our scale. But this isn't true. There are very different materials that make up our Earth. Also there are accumulations of resources like sand, oil, uranium, ores that make up fields of a material that has a very different density than the surrounding rock.

This is something we can use in geophysics. Imagine we take a very sensitive scale and measure at different points on Earth, we would get different results for the subsurface. Of course this wouldn't work with our own body weight, anyone who has weighed in on a couple of consecutive days knows that body weight can fluctuate within a range of kilograms over days. We need a constant mass for this if we want to know how the subsurface changes. This has been done with the whole world:

Gravity anomalies

Don't worry, this wasn't done by underpaid interns. Our technology has advanced so far that NASA has a satellite that can do this trick. Now this seems kind of odd. A scale that doesn't touch the ground?
Well, I told you before that we just need the gravitational attraction of two objects. We do not necessarily need to squeeze a mechanical device like a scale between those two masses. Another way to do this is to measure the displacement of said mass on a spring or in a magnetic field. This way we get the attraction of the mass to a location on Earth.

So if you're looking for weight loss look at the map above, and look for a „blue place“. You will see the scale go down when you measure there. Of course, your mass has not changed but the scale was calibrated for a different gravitational attraction. However, we might encounter a slight problem here: Probably your scale isn't accurate enough to pick up this change. But a geophysicist can really profit from these gravimetry measurements even though they won't get us out of adjusting our diet. Guess the only way to lose weight, still is eating less.

Good luck with your New Year's resolutions!

The Apocalypse - a Geoscientific View

blog@dramsch.net (Jesper Soeren Dramsch) — Fri, 21 Dec 2012 11:47:53 +0100

Today is a fun day.
Some New Age guys decided that an ending calendar of an ancient culture can only have one meaning:
The world is going to end.

Homer Simpson on the end
Copyright Matt Groening

Now this happens quite often and some people will always tell you that this world is going to end²¹. This isn't much different from the guy on New York Times Square with signs hanging from his shoulders, telling us that "The end is near".
But there is a difference to all the other prophecies. It's not that the Mayans or rather the New Age guys were right, the big difference is that Roland Emmerich learned that "Catastrophe sells". The day after tomorrow was the first step, taking every scientific inaccuracy he could find and exaggerate it into a vicious nature defending itself against those evil humans. It worked, people loved the story and personally, I think it's a fun movie to watch. The next movie Roland Emmerich decided to be a good idea, was "2012" and marketing decided it was a good idea to do some viral marketing. Consequently, it went viral and a lot of people started believing in the 2012 myth.

The movie itself was a catastrophe of its own. It wasn't quite as much fun as the Day after Tomorrow, but it contained just as much pseudo-scientific trash.
The reaction to the movie was so huge that NASA launched a website busting the most common myths²².

How about I leave astrophysics and ideas about Planet X to NASA and talk about something I do know something about:
Earth.
The most common ideas of a world coming to an end, include a couple scenarios, most of them inspired by the movie 2012.

Geomagnetic reversal
Melting and breaking of plate boundaries
Melting of the core or/and mantle
Increased seismicity

Let's work at this list a bit and have a look at

Geomagnetic reversals

Magnetic field lines of Earth's magnetic field.

Early in school we learn that our Earth has a magnetic field. We can use a compass to find our way back home we usually explain this with a normal magnet that everyone can relate too. It's easy and we can understand it quite good, but unfortunately this analogy is wrong.
Earth has an inner core that to a large part consists of Iron, however the core is not a permanent magnet²³. It would've been such a nice and easy explanation and now we have to explain it in some different way. This explanation includes the hot iron currents in the outer core that function as a coil and some source providing an electric charge. These circumstances causes magnetic induction that creates a strong magnetic field. However this field isn't a nice clean magnet with two poles at each side, a so-called dipole. A small part of this magnetic induction creates different poles that make up a so-called multipole. These don't affect us in normal life, but it might show you that Earth's magnetic field is more complex than that elementary school analogy.
Now we're getting to the geomagnetic reversal. This is something that happens every couple million years and it will happen again. However, we need to realize that Earth is a patient lady and takes its time. This geomagnetic reversal takes up to 10.000 years, which is about the time the Holocene started to now. During this time the magnetic field becomes chaotic, it doesn't just disappear. So even if a geomagnetic reversal "started today", we wouldn't realize because it is a slow process and happens gradually. Additionally, it wouldn't be the end of the world.
But just for the sake of argument, what if the geomagnetic field would just disappear?
Studies suggest that the flux of solar plasma into the ionosphere would induce a new magnetic field²⁴. Additionally, this would probably give us some spectacular auroras.

Melting and breaking of plate boundaries

This was a pretty spectacular image from the 2012 movie. The tectonic plates started breaking up like ice floes but instead of water there was hot molten rock underneath. I believe this stems from a deep misunderstanding of Earth's mantle, volcanism and how rock turns into magma. Let's start out with Earth's mantle.
We know that tectonic plates, making up the crust, float on Earth's mantle. Driven by convection of the mantle these plates move. Now this is pretty clear but from this point on there is something a lot of people get wrong. Earth's mantle is NOT fluid. Don't get me wrong here, I even had a lecturer at university tell me that Earth's mantle consists of fluid magma. But this is entirely wrong. We know this from a simple fact that a certain type of waves does not exist in fluids, they're called shear waves. We can measure these waves traveling through Earth's mantle after every earthquake that is strong enough to send some waves down to the mantle.
Now we have to talk about magma. Since the mantle doesn't consist of magma, we get a little problem explaining volcanism, right?
Yes indeed at first sight we're at loss, but when we look at it closer, we get even more processes under which magma develops.

How magma develops.
CC-BY-SA Woudloper

This graphic show three processes under which magma develops and compares the according graph to the normal geothermal gradient. On the very left we see how the red line does not cross the green "solidus"-line. This is the normal state where rock stays solid.
The second graph shows the condition of mid-ocean ridges. This happens when tectonic plates drift apart and hot rock rises just to lose pressure from the crust above, which causes the rock to melt at comparatively low temperatures.
The third graph shows a hot spot, which would be the classical idea of volcanism. Hot material from below rises and heats up the crustal rock. If you look at the graph, the temperature is at least 200° hotter than the mid-ocean ridge temperature. We find this kind of volcanism on Hawaii, where a hot mantle plum heats up the crust.
The fourth graph is an example of volcanism at subduction zones, where a tectonic plate dives under another plate because of converging motion. We see that the temperature gradient is just like the normal gradient but our melting point is shifting down. This is an effect that comes from the subducting sediments. They carry different gases like H2O or CO2 that decrease the melting point of the surrounding rock, making it melt at even lower temperatures. We can observe this behavior at the Andes in Chile.

Gedankenexperiment for melting of core vs. breaking of plate boundaries

Now if we think about it, the entire mantle was molten in the movie, breaking up our crust. Since we cannot blame a mysterious source of H2O or CO2 in the ground and pressure is a direct effect of gravitation, the mantle would have to heat up by itself in the hot-spot way. This would require some amount of energy. Let's play this gedankenexperiment through.
If we assume a specific heat capacity of the mantle of 914 J/(kg*K)²⁵ and a mass of 4,08 · 10^24kg, it would take 3.73·10^27 Joule to heat up the mantle by one degree. This is equivalent to an explosion of 892 petatons TNT. I don't think anything that induces this heat in the mantle would leave much life on the surface to suffer through the apocalypse, if you know a way, feel free to leave a comment, but remember that we need more than one degree to actually have the mantle start melting.
But we can work a bit further with this gedankenexperiment. This energy source would induce such an amount of energy that the mantle would expand by 87m to every side, considering a thermal expansivity of 3 x 10^-5 K^-1²⁵. This might have the effect of a boiling egg, where the crust cracks open because of inner expansion, throwing us into the scenario of the decompression melting at mid ocean ridges. Nevertheless, we would still need this enormous energy coming from nowhere all of a sudden, leaving all life on Earth intact to have them suffer a violent magmatic death.
Kind of unlikely, if you ask me.

This kind of thing cannot happen all at once. You know this from the kitchen, when cooking potatoes, you cut them up to get dinner ready in time and Earth is quiet a big potato to cook all at once. So how do we know, we're not at the end of the heating process and tonight the cracking of the crust starts?
Well, thermal expansion would be a process that happens along the way, while heating and satellite grids did not pick up any expansion of the Earth. If for some reason no thermal expansion happened and the mantle was just melting under our feet, we would've picked this one up as well. You might remember me telling you that there are certain waves that cannot travel through fluids? On December 9th, an earthquake of magnitude 7.3 happened in Japan and all the waveforms arrived as expected²⁷.

Increased seismicity

If you want to have a look if seismicity did actually increase over the last time, head over to the data of the USGS and have a look at the real-time map.

Concluding, I would say I still feel safe on this planet and you can too.
Nertheless, remember it's Friday and there are some great apocalypse parties going on. Just don't get yourself into some suicide cult party that might be awkward.
Enjoy the end of 2012, the end of the world is still a bit into the future.

A Global Lithological Map

blog@dramsch.net (Jesper Soeren Dramsch) — Mon, 17 Dec 2012 12:34:00 +0100

It's colorful, it's huge and it's a hundred times more detailed than its predecessors.

http://www.vis.klimacampus.de/2270.html?&L=1

It's a new lithological map of the world²⁸.
The map is a huge puzzle made out of over 75 regional maps from over 300 sources containing regional geological inf-oration. However, this patchwork of geological information had two tricky parts.

''For the map, we combined the characteristics of the bedrock in different regions, like piecing together a large puzzle,'' says Nils Moordorf.
''We standardized the nomenclature of the rock types globally and eliminated contradictions as well as blind spots”.

There are some spots on Earth that aren't covered by regional maps, these had to be handled accordingly to provide a global map. Another problem is contradicting information. Inconsistencies at borders of countries led to inconsistencies in the geological information so that these had to be resolved. Additionally the sources contain different naming conventions, just like kilogram and pound there are different naming conventions for different bedrock types. Working with this load of data is really some kind of puzzle.

Carbonate rocks traversed by water streams

Now that we have this kind of information, there are quite a few possible applications.
Geology is what surrounds us - the ground we stand on;
so how can we benefit from this data?

Georisks

It's pretty simple: Different bedrock has different properties and different applications for different regions.
The most evident use are georisks and I would like to pick out two at this stage. There has been some news reporting about sink holes. These sinkholes can be of impressive size and are usually a danger to the lives of people. Entire houses drop into the ground that used to be stable. This phenomenon can happen if the geological soil below the soil you build on gets eroded. There are some regions that can be especially prone to this weathering: Lime stone and salt domes²⁹. They are soluble and ground water might leave huge cave systems where salt used to support the ground. These systems are called Karst and can be very beautiful but just imagine where all that water comes out of the rock and how many caves must be incised into the seemingly hard rock.

Landslides

Landslide simulation - USGS

Another example that becomes more and more important with growing populations are landslides. They are not very well understood and can be triggered from a diverse spectrum of causes³⁰. However, we can identify a couple of risk factors. One of these factors can be that sediments are lying on top of a layer that is impermeable to water. This way rainfall can gather at the bottom of the sediment on top of the impermeable layer and eventually function as a lubricant for the overlying sediment.

Natural Resources and Sustainability

But we can apply this research in other fields as well. In terms of natural resources this map can give indicators for the long-term availability of silicon, phosphor and possibly other resources. These serve as nutrients in the ecosystem but are also important resources that can be used for exploration. As we're already looking into the storage capabilities of the ground, we might as well point to the ground being a carbon storage. This research is applied but isn't limited to climate research as carbon and organic matter in general are important in many processes and coupling mechanisms.

Groundwater

This new map has already been used with respect to groundwater. When we drill a well for groundwater supply, we need a property of the reservoir rock called permeability. This basically indicates how well ground water flows through certain rock. This is what researcher had a close look at, they used these rock properties from the global lithological map and obtained the global groundwater permeability³¹. This might just be the tool to improve planning of wells, where fresh drinking water is still scarce.

The data of the map is published on Pangea under the Creative Commons license and contains three layers of lithological information and its combinations with subclasses. I'm particularly proud to present this kind of research since it is from my university³² and additionally the usage license is open for use.