The Way of the Geophysicist. - Science

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 service¹. 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 interface².

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 follow³ ⁴ ⁵ ⁶. 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!"

References

Google Reader discontinued - TechCrunch
Migration from Google Reader to Feedly - Feedly Blog
J is for Journal - RSS feeds - Agile*
RSS feeds for geoscience journals - clasticdetritus
highlyallochthonous RSS feeds - all-geo
Journal RSS Feeds - Ripples in the Sand
Learn about the critique against Elsevier
Thanks to Agile* and especially Matt Hall for showing me this one

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.

References

Keine Referenzen gefunden.

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 problem¹⁰. 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)¹¹

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"

References

Foerster - Brochure on landmine and UXO detection
Finlay, C., Maus, S., Beggan, C., Bondar, T., Chambodut, A., Chernova, T., Chulliat, A., Golovkov, V., Hamilton, B., Hamoudi, M., Holme, R., Hulot, G., Kuang, W., Langlais, B., Lesur, V., Lowes, F., Lühr, H., Macmillan, S., Mandea, M., McLean, S., Manoj, C., Menvielle, M., Michaelis, I., Olsen, N., Rauberg, J., Rother, M., Sabaka, T., Tangborn, A., Tøffner-Clausen, L., Thébault, E., Thomson, A., Wardinski, I., Wei, Z., & Zvereva, T. (2010). International Geomagnetic Reference Field: the eleventh generation Geophysical Journal International, 183 (3), 1216-1230 DOI: 10.1111/j.1365-246X.2010.04804.x
Nuclear Overhauser Effect
TOH, H., T. GOTO and Y. HAMANO (1998): A new seafloor
electromagnetic station with an Overhauser magnetometer, a magnetotelluric variograph and an acoustic
telemetry modem, Earth Planets Space, 50, 895-903 Terrapub

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!

References

Keine Referenzen gefunden.

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 end¹⁴. 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 myths¹⁵.

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 magnet¹⁶. 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 field¹⁷. 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)¹⁸ 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^-1¹⁸. 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 expected²⁰.

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.

References

List of apocalyptic events - Wikipedia
http://www.nasa.gov/2012
Magnetic Field of the Earth
http://dx.doi.org/10.1051/0004-6361:20040154
Wheeler, J. (2005), Geodynamics by D. L. Turcotte and G. Schubert. Cambridge University Press, 2002. No. of pages: 456. ISBN 0 521 66624 4 (soft covers). ISBN 0 521 66186 2 (hardback). Geol. J., 40: 246. doi: 10.1002/gj.987
Earthquake Summary for 09. 12. 2012 in Japan M7.3 - USGS

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 world²¹.
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 domes²². 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 causes²³. 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 permeability²⁴. 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 university²⁵ and additionally the usage license is open for use.

References

Hartmann, J., & Moosdorf, N. (2012). The new global lithological map database GLiM: A representation of rock properties at the Earth surface Geochemistry Geophysics Geosystems, 13 DOI: 10.1029/2012GC004370
Wikipedia - Karst
Landslide Blog
Gleeson, T., Smith, L., Moosdorf, N., Hartmann, J., Dürr, H., Manning, A., van Beek, L., & Jellinek, A. (2011). Mapping permeability over the surface of the Earth Geophysical Research Letters, 38 (2) DOI: 10.1029/2010GL045565
GLiM - Global Lithological Map Project

Why bother? [Data Protection]

blog@dramsch.net (Jesper Soeren Dramsch) — Wed, 12 Dec 2012 10:17:00 +0100

I've been talking about your data in the last post. About how we're gonna talk about securing it. But why even bother, what is our motivation to save our data? Facebook, Instagramm and Foursquare are built around sharing private things in public. The entire world seems to revolve around the "likes" we get for sharing our story. What is our motivation to secure our data and keep it private?

Well there are several reasons I would like to discuss here.
When we create data, this data contains information about us. Post a funny status on facebook? Data mining can combine this funny status with other information to try and get to know you better. Oh you're meal on Instagramm has quite high fat and carbohydrate contents, if you keep eating this in high amounts, your health might be affected. Check-In at foursquare at a restaurant? Sure no problem with that, but how come that it took you over two hours between your last check-in and in between you phone was switched off. Did you do something sketchy? This is data you would want to be secured, wouldn't you?

This is data about your habits and about what you do, but there's also data that is of higher value to you. Be it your diploma or the video of your child's first steps, you're not gonna be happy when that is gone. Maybe you even have data you monetarize which should be saved in some sort of way as well.

Right now I would like to categorize your data into different classes. I suggest four classes here that are very different in importance and impact:

1. Why bother – category

Is it ironic that I am trying to convince you that you should save and secure your data, but the first category I talk about is a category of data with no value whatsoever? Well, no. This category is the least important category, it will serve as a fall-back option. However, I want to spark an idea that all your data can be valuable. Just a couple ideas how data you would initially sort into this category might not fit here after all:
Example one, is my favorite example and it is quite absurd. There are some twitter accounts out there that are dedicated to post the bowel movements of the owner. This is something of no value to the world whatsoever, but when you have an appointment with a proctologist, he might be able to get some valuable hints from information like that.
Those funny posts on facebook are used by facebook to show you personalized advertisements. The problem with facebook is that they don't just give you personalized advertisements, they sell your data. One post alone isn't all that bad, but in combination we will get to category two.
Already adding different friends and groups of friends to facebook will reveal something about yourself, maybe category one is even the hardest category because there can always be something that kicks it out of this category.

2. Cheaper by the Dozen – category

Statistics today can do a lot with data. Take a quick look at facebook, or google or any other big internet advertising platform. When I posted about London I suddenly got some nice adverts for cheap London hotels. When I commented on something about Red Bull I got ads for some nice Red Bull discounts. Now this is pretty easy to comprehend. But patterns and systems in data can be handled by data mining and this data can tell a lot about you and what you like. Now seriously some guys did a proof of concept on a „gaydar“ checking friend networks on facebook for the sexual orientation of a target ²⁶. I have already talked about how data from category one can easily be aggregated and slip into category two, if the gaydar didn't convince you, I'll just show you a real life example. This is data from facebook, my personal friend network. It took me ten minutes to create this and the colours were created by an algorithm, not by me. And this is pretty much exactly how my friend network works.

A couple singled out dots from people I know from somewhere, but don't know any of their friends. Surrounded by big clouds of networks that have a couple overlaps, from university and hobbies. If you think about it, this colouring was only taken from the interconnections of my friend network and a simple 10 minute playing around yielded a good overview how my friend network looks like and where the best connected people hide. This way I actually found that a friend from a hobby has connections to my friends back home from school.

3. Keeper - category

These are your family pictures, your memories and your dreams. You would maybe show them to some people and even post them on the internet, but losing those would be a bummer. This is data worth securing. We will discuss different possibilities to backup your data and briefly touch the subject of physical security of data. I believe this category is pretty clear and easy, you can tell whether you want to keep this data by all means or not.

4. Don't touch it – category

You might not want your diary being read by anyone. This is the category of data that is very personal. You don't want to lose it and you want to keep it to yourself. This will be interesting to handle! How do we keep something secure when we don't want anyone else having access to it?

If you only have data, you really do not care about, you are right to ask - why bother. In any other case you should consider following this series, to be able to know how your data can be protected and how you are vulnerable.
We will find appropriate way to work out how our data can be safer in physical as well as electronic ways. Suggestions are highly appreciated on what you would like me to write about, since this field is so wide spread.

References

Gaydar - Proof of Concept

Zombies, Run! [App Review]

blog@dramsch.net (Jesper Soeren Dramsch) — Wed, 31 Oct 2012 00:05:00 +0100

Never in life I saw myself as a runner.

Well to be exact I never liked short runs but somehow I forgot that I like long runs. Here in the UK I took up running again and my motivation stuck more or less. Often I would walk or get slower. And then I found this awesome app for my Android phone. Let me tell you the story of the first time I used this app.

It was 6 o'clock in the morning and I was getting ready to run and try my new app. It cost me 2.99 because it was on sale and I wanted to try it for quite some time already. When I was just ready I realized that I had forgotten my earphones at work, so I figured that no one will take offense if I just have the audio run over speaker. I mean, it's six in the morning.
The street was cold and I ran into a slightly foggy environment. No one was up yet and the red-ish yellow of the street lights did a lot to the ambiance. The story started out quite interesting and just when I took the turn into the woods, the zombie part started. Now when I say woods, I mean a dark path through a patch of plants in my neighborhood. However, it was so dark my eyes did not adjust fully the entire time I ran there. The story is set up like a village talking to you over radio, so me holding my phone in my hand just added to the experience. The week-end before my girl and I had just finished watching the first four Resident Evil movies. You might imagine that I had quite a scene running in my head.
You start seeing things in the dark.
You heard things in the underbrush.
So when a zombie rush attacked me, it was just convenient that I could sprint my way out. You run along the dark path. Don't dare to look back. And when you finally see the light of the street on the other side of the path, the story accidentally progressed from the woods to a parking lot too. Let me get this straight, the app isn't that good and it was a happy(?) coincidence, but in hindsight it was awesome. While I was there, it was scary as hell. Then you run up the street occasionally cars pass by. You wonder why no one bothers to help in a Zombie Apocalypse... Wait, am I getting to much into the game?

The game is available on Google Play and Itunes. It is not free, but definitely worth the investment.
There are over 40 missions and the first one was already a lot of fun. You can set your mission to be 30 minutes or 1 hour. Then the app will mix in the right amount of music from a playlist you feed it. For this reason I installed Winamp as well to be able to create and share playlists.
The game dynamics is an audiobook with gaming elements. You listen to the story and become Runner 5. On the way you automatically pick up useful things. Those things can be distributed to the base if you reach it. But be careful, if you hit the switch at the start and enable zombie chases, now and then zombies will approach you and you have to throw in an interval of sprints to not lose items or maybe even your life!
(Seriously the game dynamics had me quite into it, so if you run in an urban environment, think twice about the zombie chases, the streets aren't as empty as you want them to be.)

I would recommend this app to anyone who never really liked running and wants to give it a shot.
It's great fun and really gets you going. If you thought you can't run 30 minutes, try this app. Maybe you'll run slow but you keep running, if you really want to.
Oh and did I mention that I finished my usual round in about half the time?

And a plus, you train for the Zombie Apocalypse!

Happy Halloween!

The Zombies are coming!

CC-BY sookie :: Flickr

References

Keine Referenzen gefunden.

The l'Aquila trial: Getting the big picture

blog@dramsch.net (Jesper Soeren Dramsch) — Sat, 27 Oct 2012 17:59:00 +0200

In April 2009 a devastating earthquake hit the town l'Aquila in Italy. Destroyed buildings leave 308 persons dead and over 22 thousand have to flee to government funded shelters. This as it is, is a tragedy on many levels, but this week the aftermath pushes l'Aquila back into the media and leaves the world wondering about the Italian justice.
The Royal Society²⁷ and the American Geophysical Union²⁸ issued statements, while the European Geophysical Union²⁹ asked the Twittersphere to discuss about the decision in court.

l'Aquila, Italy after devastating earthquake. Picture by wolfgango on flickr. CC-BY 2.0

Six Italian scientists have been convicted of manslaughter and are sentenced to six years in prison, reimbursements to the families of the deceased in the range of 130.000 per victim and a ban from official positions. Throughout the trial prosecution tried to make it clear that this case is not about earthquake prediction but about "inexact, incomplete and contradictory information" ³⁰.

This verdict is very complicated and I think it is important to try and illuminate all sides to it. Now in general this is a nice idea, but there is already one problem to it, the judge Marco Billi did not yet publish the verdict. However, we might want to start looking at the juridical side.
When I read comments on the sentence there were a couple comments stating that this verdict is a retribution³¹. Now those comments were mainly posted by users from the US, which is not a coincidence. In law theory there are different basic principles these are combined in different ways. One of the main motivations in the US is retribution. Whereas, in Italy they use a principle called "Social Defense".

Social Defense is supposed to provide a form of special and general prevention. Special prevention to encourage the culprit not to repeat the crime and general prevention in the form to prevent others from doing the crime. Retribution (in theory) takes the smaller part in Italian jurisdiction. However, this leaves us with the problem that manslaughter has the prerequisite of intent in any jurisdiction I know. This should eventually lead to the case being dismissed. (Please remember I am no expert on this, I just read up on this matter for this article.) Additionally, we need to keep in mind that the verdict can and will be appealed by the defense.

The damage is done.

The Verdict of the l’Aquila #Earthquake Trial Sends the Wrong Message bit.ly/Tz3hW8
— Geozon Science Media (@geozon) October 24, 2012

The guardian draws an interesting parallel to the Galileo trial in 1633³². This also was a trial about communication but had a long-lasting effect on science in Italy for the next hundred years. Although an appeal on the verdict will probably save the scientists from jail, the message is sent out that scientists who do not communicate the risk of certain hazards clear enough will face charges.

Continue reading "The l'Aquila trial: Getting the big picture"

References

Statement of the Royal Society on l'Aquila trial
Statement of AGU on l'Aquila trial
Twitter Discussion on l'Aquila trial
Scientific American on l'Aquila trial
They would rather use vocabulary like "revenge" and "deserved", but I take the freedom to rephrase it.
Guardian compares l'Aquila trial to Galileo verdict
Guardian - Italy earthquake and banknotes
Nature News - New twists in Italian seismology trial
Annals of Geophysics – Earthquake Forecasting

Amazing fluid dynamics

blog@dramsch.net (Jesper Soeren Dramsch) — Fri, 19 Oct 2012 19:13:00 +0200

Fluid dynamics is just boring equations, right?
Well have a look at this video and think again!

Food-dye is always fun, especially when you get to mix it and get some colourful joy. But this is just amazing how this liquid creates "laminar flow". If there were turbulences in the fluid while turning, you would not get the droplets nice and separated in the end.

Very similar equipment is used to determine the viscosity of fluids. You measure the torque you need to turn the object in the middle and from this you can calculate the viscosity of the fluid where the droplets are in the video. This is a great example how to visualize some pretty tough science in a very good way.
When I took a class on fluid dynamics, I had a pretty hard time visualizing viscometers and the different impact of turbulent vs. laminar flow. This would have probably helped to get a better start into the topic. In the end fluid dynamics is essentially everywhere and the difference between turbulent and laminar flow are pretty important in a vast amount of applications.
The Fraunhofer Institute is looking into sharkskin mimicry for planes and ships to reduce fuel consumption³⁸. The surface of planes and ships significantly accounts to fuel consumption due to aerodynamic drag. Modifying these to facilitate turbulent flow will reduce the drag and make travelling more economic and reduce the impact on our environment.

Read the full story about it about awesome fluid dynamics on A Science-based life

References

Fraunhofer Institute, Research News, Special Edition, 05/2010: http://amplt.de/n1

A guide to internships in foreign countries

blog@dramsch.net (Jesper Soeren Dramsch) — Wed, 17 Oct 2012 17:17:00 +0200

Internships in foreign countries sometimes confront you with cultural differences you were not aware of. It's hard to prepare for those. There is however some stuff you can prepare for. Apart from the target language, you might consider some of the following questions.

What kind of money do they have?

A map of the Eurozone and the status of the surrounding countries and territories.

EU member states using the euro (Eurozone)

ERM II member states

Other EU member states

States using the euro as a result of a treaty with the EU

States which have unilaterally adopted the euro

Now with the Euro in large parts of Europe, it has become easier to travel or even work abroad. Your german Euro is just as good as the Euro in Spain, Greece or Austria. This is exactly why I forgot that Norway and has a completely different currency. I am aware that Norway is not even part of the European Union, it's just somehow the Euro gives you some sort of self-conception.
Now this isn't bad in particular, since you can always exchange money in your destination. This is also what banks suggest and what has worked in my personal experience. The best exchange rates will always be in your destination, when buying the local currency.
It might be hard setting up a bank account, but banks are always happy to exchange your money for "a small fee". So if you do want to exchange it, take a heap of cash. That way you will get the best deal sometimes even without an extra exchange fee and just the currency spread.

What kind of outlets are there?

Euroflatplug (Typ C)
French system (Typ E)
Schuko-System (Typ F)
British System (Typ G)
Swiss System (Typ J)
Danish System (Typ K)
Italian System (Typ L)
Wikimedia Commons: BlankEurope.png;BlankEurope.png: Happenstance, Hoshie, Avala, Quilbert; derivative work: Nameless23

Now this is a tricky one, I did not forget about in Norway but they have a system compatible to Euro outlets. Then it got me cold in the United Kingdom.
Which basically led me to ordering about 7 converters from Amazon. In all honesty I still have one in the original packaging, but I just didn't want to bother switching one converter around for everything I do.

Left right left, or the other way around?

In Germany we teach children crossing the street to first look for cars coming from the left side, then right and re-check left side. Now you get pretty good at screening the street when you get older. That is the problem, the more you get used to it, the harder it will be to get used to left-sided traffic as in the UK.
My very first encounter was trying to get into a car and finding myself on the driver side of the vehicle. That was a little embarrassing at first, but also made it very clear to me that I should really be alert when in traffic.
Additionally, I really haven't made it any easier on myself by visiting Germany every other week-end. The first week-end back home I felt like I was starting all over again. The only way to really get along in this changing environment is constant awareness. So when I cross the street, I check if I see any cars and can get the direction of travel from that. Then I start the children approach left-right-left or right-left-right. Eventually, this results in me checking both sides several times, which might make me look like a paranoid nutcase crossing the street, but well, I survived, right?!

?? Drives on right
?? Drives on left
No Information

Sweat the small stuff

You're probably flying to your internship. Do you know how to get to your temporary place? Do you have all the emergency numbers written down? Remember that Internet Roaming can be very expensive, so you will not be able to get information from your e-mail without paying for it.
Get your directions to the office before your first day. I myself got terribly lost, because I just followed the road we took by car the first day.
Two tips that helped me fit in with the company a lot, were asking for the dress code and asking for the time to start on the first day.

Don't sweat the small stuff

You're arriving at an airport. It's a microcosm that probably has everything you need. Here in Gatwick it's no problem to find an internet terminal, get cold medicine, exchange money, get a coffee or go to the pub and buy milk for the next morning, without leaving the terminal. Just don't freak out, if everything fails, there are hotels around where you can get settled and also have internet and phones to connect to your company. Believe me, my first day in London was pure chaos, but it all worked out in the end.
Don't worry you are still an intern and in the end no one will really care if you came in blue jeans. (Don't push it, I have never seen a place where cargo shorts were fine...)

In the end, you are there to learn something and if it is just about the company culture.
This list is everything but exhaustive, so if you have encountered some other challenges, leave them in the comments!

References

Keine Referenzen gefunden.

Talk nerdy to me - a TED talk

blog@dramsch.net (Jesper Soeren Dramsch) — Fri, 12 Oct 2012 08:45:46 +0200

A wonderful TED note on science communication³⁹:

You don't need to be a fabulous presenter.
You don't need to publish all your research in Nature.
You don't need to make it perfect.

Go out there, tell people about your fascination. Maybe start with a friend or your family. Their probably not great for for constructive criticism, but they are practice and they will give you confidence. Go out and partake in a competition like a Science Slam or Famelab. Maybe start a blog or send out tweets about your fascination.

This is not just for your audience. As Einstein put it:

If you can't explain it simply, you don't understand it well enough.

I absolutely agree with this quote, as it is what I experienced very often, with myself and also with others.

Go out there, share what you know and love!
You know something and that something is beautiful, don't be selfish, share it with your audience.

References

Although, is having the science communication plattform TED talking about science communication some weird form of "TEDception"? via It's ok to be smart

Curse of a geophysicist: Those waves!

blog@dramsch.net (Jesper Soeren Dramsch) — Wed, 03 Oct 2012 15:01:00 +0200

Within the last days a couple of amazing physics videos have been passed along on Twitter. My personal favorites are the two I want to talk about now. They basically involve some sort of experiment with oscillation or wave-like motion, with a twist. But see the first video for yourself:

Coupled pendulums

Personally I find it amazing. 32 metronomes start out completely independent on a moving table and they gradually align!
First of all the choice of colors is very beautiful but has no effect on the experiment, however, the weight of the metronomes are approximately set to match the same speed. The weight on a metronome determines the vibration period by the inertia set on the lever. This or a multiple of the base inertia is necessary to make this experiment work.

Why do they line up?

The metronomes are on a moving table and therefore can be viewed as a coupled system. Every metronome exerts a force on the moving table and opposing forces cancel out. With 2^5 metronomes you can be certain that at some point of time some metronomes will exert a force into one direction that is stronger than the opposing force, slightly moving the table to that side. Now this is where the coupling really comes into effect. When the table moves the period of the pendulum in direction of the movement of the table will be reduced, forcing the pendulum to swing to the opposite direction faster. On the other side (literally) the pendulum motion will be elongated, extending the movement in that direction. So in this exact moment the metronomes started to align just a little bit. Of course in the very next moment a couple of the other metronomes might exert just a different force which makes the entire process quite complicated. However, if we wait long enough the resonance of these pendulums will cause the metronomes to line up. Amazing right?

Commons User Vincent Quach CC-BY-SA

Now take another look, they line up pretty quickly for such a bulk of different complicated forces influencing each other, however at 2:11 You see something interesting happening. Far on the right in the pink row, the second metronome from the front, is aligned, but exactly opposite to the other metronomes. You can hear, it's lined up by listening to the sound of the metronomes. This is quite interesting because it takes quite some time for the last one to line up and this is because the counterweight is in sync with the movement of the table. Eventually it will line up because the metronomes are attenuated and once the metronome is just slightly getting out of sync the table movement will force the last metronome to line up.

Why do you care, you're a geophysicist?!

First of all, they're colorful and cool and those metronomes are pretty mesmerizing.
Those metronomes are reminding me a lot of geophones. The good ol' mechanic geophones work with a spring and a weight and hopefully some kind of attenuation. Those geophones are put on a moving "table" aka the ground and you measure the force exerted on them and every time a new movement comes in, the spring and weight in the geophone are affected again. Now I was talking about attenuation and there is a reason for it. Without attenuation the forces on the metronomes and the forces on the spring and weight would sometimes build up without any counterweight stopping the motion, which would result in a lot of broken geophones or quite some pendulums ripped off of metronomes.

Uncoupled pendulums

I told you there was a second awesome video. Well this is just beautiful. Fifteen weights on a string with linearly increasing length:
Continue reading "Curse of a geophysicist: Those waves!"

References

Keine Referenzen gefunden.

The three virtues

blog@dramsch.net (Jesper Soeren Dramsch) — Fri, 07 Sep 2012 08:48:03 +0200

Don't forget the three virtues of a Geophysicist, namely:
True Love, True Friendship, True Amplitudes. ~ M. Tygel

This happens to be my favorite quote about geophysics.
A fellow writer asked me, what this quote was all about. So I began to elaborate on this.
The part about "True Love" appears to be the easiest to me. Having met the woman who is more than I ever dared to dream of, puts me in the position to say this true love gives me strength and support I need to move mountains. (What a lovely idiom for a geoscientist, right?!)
Now I hear some say "friends come and go", but you should have your couple of friends that can count on you just like you can always count on them.
Those are the two ingredients that keep the geophysicist from going crazy when he's entangled in some fancy dimension of Fourier- or Hilbertransforms. (Or maybe just missed the conversion from feet to meters?) Now this part probably made my friends reading this quite happy, but didn't solve the real puzzlement about the amplitudes.

Let's see.
I work in seismics and I just happen to know the quote is from a fellow geophysicist in seismics. What we do in seismics is sending acoustic waves into the ground. Those waves waves get reflected at inconsistencies in the subsurface. So they get back to the surface and that's where we set out our recorders to pick up an image of the earth we stand on.

Continue reading "The three virtues"

References

Data Protection

blog@dramsch.net (Jesper Soeren Dramsch) — Wed, 05 Sep 2012 08:52:19 +0200

Those of you who have been following this blog over the past months, know that I am working in a big company. In fact Schlumberger is so big, they have policies and trainings for everything. Yes, even one for lifting boxes in a safe way. Therefore, it probably doesn't surprise anyone that this company handling big, important, expensive data has certain policies for data protection. Just recently the worlds biggest oil company was subject to an attack⁴⁴:

Saudi Aramco... | Facebook

Saudi Aramco Responds to Network Disruption On Wednesday, Aug. 15, 2012, an official at Saudi Aramco confirmed that the company has isolated all its electronic systems from outside access as an early precautionary measure that was taken followinga sudden disruption that affected some of the sectors of its electronic network. [link]

Now why am I writing about this?

This might just as well be something you should be worried about.
Protecting your data doesn't just mean, protecting it from others, but also keeping it in a place that it doesn't get lost. Yeah, probably almost anyone of us had some accident were data loss happened. Some external hard drive crashed or got stolen, your phone got lost, or something happened to your Desktop PC. From this point on we can probably say, that our Desktop PC is the safest from all of these devices. They're not the most valuable item in your house and if a thief has the choice to either carry your customized high-end computer out of your apartment or some off-the-shelf flat screen, what's it gonna be?
Far more vulnerable for getting lost, stolen or destroyed are modern laptops, phones, external drives and tablet PCs. They're hyped and I myself am writing this article on a laptop in a train from Birmingham to London. There are even thieves specialized on theft of electronic equipment. I'm not trying to get you paranoid, but some actions might just help your valuable family photos be saved from vanishing.

This will be the starting point on a series of data protection in an age where security can barely hold pace with the demand of accessibility of data. Look at Dropbox for an instance. Dropbox is great for having your data everywhere, even your phone. But when it comes to security they have had a lot of issues where your data was accessible for anyone⁴⁵, spammers got email-adresses of the users⁴⁶ and passwords were leaked⁴⁷. However Dropbox seems to learn and hire some specialists to get the security side up to standards.⁴⁸ ⁴⁹ This will be the opportunity for you to take data security in your own hands, in small steps, so anyone can do it!
We will have some introductions to physically securing your data. But my main focus will be on the software and data part of this.
Yet again, I am no expert on this field. I do geophysics and I just happen to be a nerd that likes to play around with stuff. When I decrypt my fully encrypted dual boot laptop I always feel a bit like a nerdy James Bond. Maybe I can share some of this fascination with you.