The last time we visited the southern part of the East Africa Rift, we were responding to an unusual series of earthquakes in December 2009 that shook northern Malawi. The faults responsible for these events had not produced any earthquakes historically, and thus caught everyone by surprise. The unexpected occurrence of earthquakes on these faults highlights our poor overall understanding of how the African continent is slowly stretching and breaking apart.
This time, we return to this part of the rift system as a part of a more comprehensive effort to understand the underpinnings of this continental rift using a spectrum of geological and geophysical tools and involving a big international team of scientists from the U.S., Tanzania and Malawi. In the coming three weeks, we plan to deploy ~15 seismometers in southwest Tanzania around the Rungwe volcanic province, the southernmost volcanism in the East Africa Rift system. These stations will record small local earthquakes associated with active shifting of faults and moving of magmas at depth. They will also record distant earthquakes that can be used to create images of structures beneath Earth’s surface and map the faults and magmas.
This is an example of the data we have collected. Right is to the East and left is to the West. This is a cross section of the Earth about 65 km long. The blue is water. The water depth here is about 5 km. The red and gray colors are a cross section of the rocks below the water. The flat layers are sedimentary rocks. The lumpy bumps (that is a technical term!) consist of blocks of continental crust and of the mantle.
Thank you to the Science Party. We had a total of 20 scientists, including undergraduate students, graduate students, post-docs, researchers, and professors. On Leg 1 we had 14 scientists and on Leg 2 we had 10 scientists. Four scientists weathered both legs. Six joined us for Leg 2. I am very grateful for all your efforts on behalf of the Galicia 3D science. I hope that you learned a lot, had a good time, and met other scientists for the first time. I suspect that we will meet one another many times in the future.I look forward to that!
This is the Technical team and the Science team for Langseth Leg 2.
radar as well as all the speed controls. There are two smaller control panels
on the port and starboard sides of the bridge for work that
involves careful maneuvering e.g. picking up OBS's.
The image on the left shows swath coverage. The image on the right shows an active ping through the water column.
A screen capture of the Spectra display. The image on the left shows active binning of the MCS data.
The image on the right shows the bins being infilled (filling holes).
From left to right breakfast, lunch, and dinner.
In the center image the galley staff made up of June, Hervin, and Brian pose behind a lunch of pizza and soda.
I was sent to join this cruise half way through because a lot of the scientific party had to leave and nobody more qualified than me could be found at such short notice! I have never been on a cruise before and had no idea what to expect, or any idea how complex and time consuming 3D seismic acquisition is. I have learnt so much about the technical side of acquisition and a little bit about the processing side; however I have also gained a lot of non-scientific tips and tricks!
Here are my top 5 tips:
1) ‘Boring science is good science’ – If you are bored on a 6 hour watch that is a good thing because it means that everything is running smoothly and good data is being collected. Having things to do is always a bad sign! Things have been running pretty well recently and as a result I have greatly improved my crossword skills.
2) Things will break, don’t panic! – This is a hand me down ship filled with second-hand instruments from industry vessels. Because of this a lot of the equipment is temperamental and repeatedly needs to be fixed. However, I have also seen instruments that have been offline for days randomly start working again so you never know!
3) Duck tape has a million uses – There is no end to the list of things duck tape is used for on this ship: keeping weights in place on streamers, keeping your laptop on the desk during bad weather, taping your ladder to your bunk so it doesn’t bang during rough weather and keeping ropes in place on the deck to name a few. It seems like any problem can be fixed with tape.
If you don't want your office chair rolling around or you need a cable tie just use tape!
4) Hoard food – When food you like is put out in the mess then take it while you can. A few days ago a gigantic tub of mini snickers and bounty bars was put out in the mess….I have never seen chocolate disappear so fast!
5) Taking a shower is the most dangerous activity on the ship – I recommend keeping either an elbow or hand on the wall at all times so you can feel when you start to move. I think taking a shower is probably the best form of exercise on the ship because of the amount of effort and energy it takes just to balance. Also, never soap the bottom of your feet in rough seas. That is probably classified as an extreme sport!
Located next to the Galley we have our Library which has a lot of good books (I was reading the Che Guevara's travel book before the beginning of this part II, I really want to finish it!) and these excellent chairs...they're really comfortable, believe me. You can also find a variety of mystery, fiction and scientific books on the shelves.
The library with a wide variety of books
It's a little bit small, but if you think we're in the middle of the ocean, the luxury of having some equipment must be appreciated.
The gym ... be careful when the ship is moving!So, there is a treadmill, some free weights, etc. Be aware of the pitch, roll and heave! These are the movements made by the ship. Instead of explaining them, I'll post an image which can perfectly illustrate what I'm trying to say.
The differences between pitching, rolling, and heavingFor those who appreciate an indoor sport, we also have a ping-pong table. It's located one level below the Galley, at the Main Deck. I didn't use this table either, but I'll launch a challenge: Try to play ping-pong during rough seas! Imagine how cool a ping-pong game is inside a ship facing waves of 5 or 7m (or even higher).
The ping pong table ... this could get interesting in rough seasThank you...or should I say Obrigado?
João (John) Pedro T. Zielinski
Complutense University of Madrid/Federal University of Santa Catarina
The back of the lab where most of the preprocessing and quality control is done.
Being at sea again allows me to look back at our extended stay in Vigo (Galicia). The port city of Vigo is a unique and beautiful place. The summer months are particularly nice as this part of the Atlantic coast is rainy most of the year. Vigo is just about 2hrs north of Porto (Port wine), which is in Portugal. The proximity to Portugal and the fact that in the past teaching the English language was not stressed within the school system leads to a population that speaks a mixture of Portuguese and Spanish, but not much English. As a result my (poor) Spanish was definitely put to the test as well as my ability to communicate using what are best described as elementary level sketches.
What Vigoites lack in English they make up in hospitality and a relaxed outlook on life. In short, the idea of a "siesta" is not lost on them. While the bars (and there are hundreds if not thousands) are usually open, the restaurants do not open until 8:30 p.m., and generally not at all on Sunday. However, we did manage to find one that is, and it happened to have very good (and cheap) Tapas. Although off the beaten path it quickly became one of our favorites.
A view of Cies from Playa Samil with faults indicated by the arrows.The part that we had been so patiently waiting for arrived after almost 3 weeks in this unique place. While I will not miss being in port, I am happy to have had the chance to see and experience this part of the world as it truly is a beautiful place.
It has been a while since we last updated this blog. The reasons are many. The primary reason for the delay is that we have had singular focus in launching our next project, a project that for many is a dream come true.
Before we launch into that and officially start the 2013 field season, let’s do a quick recap of our team’s efforts since last August.
Our academic year started with a bang: our new research project, which was an unexpected off shoot of our efforts to study climate, fire, and forest ecology, was funded by the National Science Foundation in September 2012.
Since then, our team has spent much time presenting prior results, new preliminary results and processing samples. Many, many samples.
First, kudos to Nicole Davi work improving a tree-ring based reconstruction of the Kherlen Gol in Mongolia (gol = river). Many of the chronologies used were collected between 2009 & 2011 as a part of the Climate, Fire, and Forest Ecology project. The new work, “Is eastern Mongolia drying? A long-term perspective of a multi-decadal trend” can be found here.
Second, we need to congratulate Cari Leland on persisting and publishing the first paper from her thesis: “A hydroclimatic regionalization of central Mongolia as inferred from tree rings “ – link
Cari’s effort set the stage for our second paper on the climate history of the Mongol Breadbasket: “Three centuries of shifting hydroclimatic regimes across the Mongolian Breadbasket“ – link
Finally, Tom Saladyga got a nice piece of his dissertation published with the article, “Privatization, Drought, and Fire Exclusion in the Tuul River Watershed, Mongolia“ – link
We have a few manuscripts in development from our Climate, Fire, and Forest history project, which ends in 2013. And, we are very happy that Byambaa is on the doorstep of completing her dissertation. This project is coming to a very nice completion and we are thrilled.
We are equally thrilled with the start of our new project, “Pluvials, Droughts, Energetics, and the Mongol Empire”. We’ve gotten a silly amount of press here, here, here, here, and here – it has been great. Both institutions have made nice videos and overviews of the project: here is an example of WVU‘s and here is LDEO‘s. Awareness of this project has been widespread. We meet new scholars from various parts of the world and it seems they are already familiar with the new study. Neil presented preliminary results at the PAGES meeting in Goa, India – that was hard work
Amy Hessl garnered two invites based upon our work. The first was a workshop primarily populated with historians on migration and empires across Eurasia. The setting and out-discipline experience was fantastic. The second was an archeology-based workshop on Chinggis Khaan in Jerusalem – sounds like that was equally hard work!
We are now gathering in Ulaanbaatar to launch the first season of ‘complete’ field work. By complete fieldwork, I mean that we will not only be collecting tree cores and cross-sections from dead trees, but Avery Shinneman Cook will be leading the effort in collecting lake sediments in central Mongolia to better understand long-term environmental history and the impact of the Mongol Empire on the landscape in and around the ancient capitol, Karakorum.
Prior to that, we will hold a 4-day workshop introducing ourselves to our wonderful and diverse team (a dream team? Besides Amy Hessl and Neil Pederson, team members include: Baatarbileg Nachin, Hanchin Tian, Nicola Di Cosmo, Avery Shinneman Cook, Kevin Anchukaitis, Oyunsanaa Byambasuren, and PhD students, Caroline Leland and John Quinn Burkhart) and their specific research. We will visit historical sites and lakes to begin the discussion on how to address some questions originally posed in our grant: did the rise of the Mongol Empire, driven literally by horsepower, benefit from an abundant climate and a surplus of ecosystem energy? Did the construction of the Mongol population, army, and herds of grazers significantly impact the landscape? Answers to the ful climatic context of the Mongol Empire has been a primary goal of the Mongolian-American Tree-RIng Project, (MATRIP) since the mid-1990s. We finally have the chance to address these questions. We do not know the answers yet, but stay tuned.
Brief Observations on an alternative approach to Mongolia:
This is my 9th trip to Mongolia. It is hard to believe that I have visited this far-away land so many times. But, when I smell the steppe as we enter the airport, I relax and hit a new mode that is akin to putting on old slippers. I go through customs with nary a concern knowing that Baatar will be waiting for me with a warm greeting and hug. The drive to UB is filled with the same conversation – “How are you? How is Mongolia? How are things going? How is your family? How are your students? My, Mongolia has changed“. It is wonderful.
What changed for me this year was how I got to Mongolia. I typically venture west and enter through eastern Asia. This time, I traveled east, stopping in Turkey, re-fueling in Bishkek, and then flying over western China and western Mongolia.
The sky was clear upon entering western China and the scenery was stunning. Really. I stopped my movie and just drooled out the window [akin to a dog?]. It adds a few hours of travel time at most, but I’d do it again.
Scenes of Going East to go East
A new study in the journal Nature provides fresh insight into deep-earth processes driving apart huge sections of the earth’s crust. The process, called rifting, mostly takes place on seabeds, but can be seen in a few places on land—nowhere more visibly than in the Afar region of northern Ethiopia. (See the slideshow below.) Here, earthquakes and volcanoes have rent the surface over some 30 million years, forming part of Africa’s Great Rift Valley. What causes this, and does it resemble the processes on the seafloor, as many geologists think?
The study suggests that conventional ideas may be wrong. Past calculations done by scientists predict that the solid rock under the Afar should be stretching and thinning substantially as the continent tears apart; thus molten rock should not have far to travel to the surface. Led by David Ferguson, a postdoctoral researcher at Columbia University’s Lamont-Doherty Earth Observatory, researchers analyzed the chemical makeup of lava chunks they collected from the Afar. They showed that magmas actually came from quite deep–greater than 80 kilometers, or 45 miles, within the earth’s mantle–and formed under extraordinarily high temperatures, above 1,450 degrees C, or 2,600 F.
This implies that magmas are generated by a long-lasting plume of mantle heat. It also indicates that magma must make its way up through a surprisingly thick lid of solid rock, called the lithosphere. This idea has been supported by some seismic images of the Afar subsurface.
Rifting here is fairly slow—one or two centimeters a year, or 0.4 to 0.8 inches, and this may partly explain why so much solid rock persists. As the lithosphere is pulled apart, it does stretch, crack and thin. However, because the process in this region takes so long, the base of the lithosphere has time to cool down by losing heat to the colder rock above. This keeps the relatively cold, brittle lithosphere thicker than would be expected, and counteracts stretching. Sometimes, though, magma suddenly spurts long distances to the surface, and the earth visibly cracks and pulls apart during spectacular rifting events. That includes a series of events that started in 2005, and was closely observed by scientists.
Parts of the rift have already sunk below sea level. In the distant future–maybe 10 million years from now–the process will advance so far that the Red Sea will break through and flood the region. A new sea will open up, whether or not there is anyone around to name it.
In East Africa, earth’s crust is stretching and cracking, in a process called rifting. Here in the Afar region of northern Ethiopia, hundreds of faults and fissures have formed over time. (David Ferguson)
An important force driving the rifting is magma created beneath earth’s rocky outer shell, which has forced its way upward to push apart the crust. This eruption happened in the Afar in June 2009. (David Ferguson)
This crevice opened in a matter of hours, during a sequence of very large earthquakes in September 2005. It formed in response to magma being injected into the shallow crust, and is still emitting volcanic gases. This injection of magma was the largest event of its kind to be observed by scientists. (Lorraine Field)
Fresh lava erupted onto the desert floor preserves fragile surface textures, formed as the viscous molten rock cooled and hardened. Over time, these sharp features will erode away. (David Pyle)
A remote field site within the rift. Afar is one of the hottest and most sparsely populated regions on the planet. (David Pyle)
In a region that is vast, largely roadless and dominated by armed tribes, scientists depend on helicopters to get around, and on local people to act as guides and security guards. The climate necessitates large amounts of portable drinking water. (David Ferguson)
Lavas forming the rift surface cracked apart during an earthquake in 2005 to form this fault. The horizontal boundary between the light and dark area marks the pre-2005 ground surface, and shows that the area in the foreground dropped several meters during the quake. The geology of Afar provides many clues to the tectonic and magmatic process operating beneath our feet. (David Pyle)
All of us on the science team have had our turn being indoctrinated in the "perils" of XBT deployment. In this video, Luke demonstrates the proper technique for launching an XBT.
Prior to boarding the Langseth, my expectations of the food on board were clouded with visions of elementary school cafeteria slop doled out in aluminum trays and eaten with sporks and a side of plastic bag infused with milk. Little did I know that the folks on board take their food quite seriously. The three meals prepared each day are easily the most anticipated events of a crews’ day.
The galley (a.k.a. the kitchen in land dweller speak) is manned by a cook and steward who are responsible for sustaining the morale for the 53 people on board. The mess is regularly stocked with snacks like crackers, raisins, peanuts, dried prunes (yuck!), popcorn, cold cereal, microwave pasta, deli meats and cheeses, an assortment of milks and juices, coffee, tea, ice cream, and “fresh” fruits and vegetables (which will slowly be replaced with canned fruits and vegetables as the days go by). Cookies and pastries are also available at select times during the day if one is lucky enough to get there before they’ve all been consumed.
Lunch at the mess with Luke, Sarah, and Tyler.
We made it! According to the 30 minute log, which is one of the duties that we are given while on watch, we sustained up to 40 knot (74 km/hr, 46 mph) winds and ~7m (23 ft) seas for a few hours last night. That said, and aside from a relative lack of sleep, most of us seem to be no worse for wear. We also managed to travel north of our next sail line by almost an entire degree of latitude, which translates to ~111km (69 miles). We have now turned around, and are heading back to the survey area while working on streamer one. We will then re-deploy the air guns, and re-engage the survey in a couple of hours.
Same view taken this morning.
Spanish, English, and American motion sickness remedies.
My laptop's ready!