I am working for Dr. Maria Beatrice Magnani at the Center for Earthquake Research and Information (CERI) in Memphis, Tennessee. During the internship I will be assisting Dr. Magnani in her research on the fault structure in the subsurface of the New Madrid Seismic Zone (NMSZ). The presence of magnitude 7.0, and greater, earthquakes within the NMSZ have led researchers to believe that there is a complex fault system in the near subsurface zone of the lithosphere and that this system is presently active. Considering the damage of the earthquakes that occurred in 1811-1812 in the region, researchers believe that it would be important to map the fault system to better understand the following: where exactly the fault zones are located and their relation to each other, what parts of the system are active, the average resonance period for earthquakes at the fault zones, and probable causes of the stress in the system.
To better understand this fault system, Dr. Magnani started a project in 2007 with the goal of running seismic surveys along the Mississippi, which runs directly through the NMSZ, to map out the fault system. Along with a lot of preparation, this project included three summers of cruises down the Mississippi, each one mapping about 300 kilometers of the river. This summer marks the last of the cruises and the conclusion of data collection.
So, for the first three weeks of the internship and I will be drifting backwards down the Mississippi collection seismic data from a hydrophone active source array (an airgun is used as the source) and a Manta Ray sized CHIRP sensor. The shore component will consist of primarily data analysis and interpretation (basic processing is performed on the boat during the day). I am so excited!
For more information, you can look at the Mississippi River Project website at: http://www.memphis.edu/riverproject/
Yup, unfortunately, all good field work must come to an end. The last five days of our research cruise, however, were a pretty awesome way for it to come to a close. So, before I forget, I wanted to recount my last days on the M/V Strong.
Friday, June 24th –
We had planned to start our acquisition late this morning because there was a lot of maintenance to perform on the research equipment. The airgun had started leaking a little the day before, which indicated that one or more O-rings were wearing out and needed to be replaced. Also, the big compressor had since surpassed the 50-hour mark indicating its mandatory, although conservative, oil change. While Steffen and the other researchers went to work completely deconstructing the airgun, Steffen put me in charge of changing the oil in the big compressor. I, sufficed to say, was very excited about this.
Putting aside my mild disappointment that I would not get to see the airgun dismantled, I asked Kirk for assistance and we went to work. Steffen ran the compressor for a few minutes to warm up the oil, so that it would drain faster (another little trick that I will remember), then I strapped the drain hose to the bucket so that it would drain and I could go about performing other tasks. Kirk and I modified a funnel to include a long drain tube so that it could reach the input. The best thing about this funnel, though, was the fact that it had a cutoff valve and measurements, which allowed us to accurately determine how much oil we had put into the engine. At that point, it was just a matter of putting in 1.25 gallons of the new oil, wiping everything down, and putting the tools away. The entire operation went so smoothly; only a couple of ounces of dirty oil was spilled out of the drain tube. It was a supremely satisfying experience.
By the time everything was cleaned up from the oil change, the airgun was back together and we went straight to work reattaching it to the umbilical and the bouy. We were a well oiled machine (hehe). While Steffen and Beatrice were attaching the connectors, Lei Guo was attaching the shackles and I was securing them with seizing wire. We had the entire rig together and in the water in ten minutes. After confirming that the airgun was no longer leaking, the rest of the equipment went in and we were on our way. The rest of the day went off without a hitch.
Saturday, June 25th –
I’m not sure that anything remarkable happened on Saturday…oh wait…we flawlessly acquired 13 miles of seismic data along the Mississippi River. That’s pretty cool.
Sunday, June 26th –
This marked the last day of our seismic survey on the river, south of Memphis. We still had two days on the boat, starting on the 28th, performing a survey right around Memphis. We only had 10 miles left to survey (5 hours worth), so, if we started at 8, we would be done by 1 and on the road by 2:30ish, right? Wrong.
When testing the airgun, we discovered that it was leaking air very badly. So, we pull it up on deck and perform emergency surgery to replace a newly replaced O-ring that was completely blown out. The whole breakdown and reassembly took about twenty minutes, so the airgun was back in the water in 30 minutes total. We retested the airgun, and it still was leaking. Grr…
We set up the “operating table” in the galley and found that the new blue O-ring was already torn up after about ten shots. This was indicative that some component of the airgun was not aligned correctly or greased enough. So, we slowly took the entire airgun apart, piece by piece; some people were cleaning everything to get rid of any silt, clay, mud or sand particles that could be causing friction and tearing, while Lei Guo and I were helping Steffen breakdown each component of the airgun and providing him with new parts to replace some of the old ones. An hour later, everything was clean, replaced, and regreased and the airgun was back in the water for another test. Our efforts were to no avail.
Now, at this point, it is about 11 and I remember that I volunteered to cook lunch for the entire crew and research team today. So, while the rest of the team re-disassembled the airgun, I rushed around to grill the chicken, cook the rice, and fry the vegetables for a total of 14 people. Fortunately, everything seemed to come together all at once. At around noon, I got the news that they had found the source of the problem in the airgun, that everything was working fine, and we were starting our acquisition for the day. Ten minutes later, all the food was finishing at the same time and I got the pleasure of being able to tell the entire crew that lunch was served. By the way, you do not know what hot is until you have had to stand in front of a grill, on a dark steel deck, with the mid-day sun beating on your back.
We ended our acquisition at 5pm, and were started on the 4 hour drive back to Memphis by 6:30pm. Besides a stop for food and gas, it was a straight shot back to Memphis. I fell into my bed that night and passed out immediately. The day was about 5 hours longer than expected, but the experience was well worth the frustration. Oh, also, it was my birthday!
Wednesday, June 30th –
The M/V Strong had steamed two days up the river without rest to meet us at Mud Island to restart our surveying. The day before we had done 13 miles of survey, leaving about 6 miles left for the following day. Our intention was to knock out the last 6 miles in a few hours and then spend the rest of the day disentangling our entire operation from the M/V Strong.
Well, I looked down at some data that I was processing and the next thing I knew I was getting tapped on the shoulder by Steffen who informed me that it was time to take everything apart. The next three hours were a scramble of disconnecting equipment, packing it all into boxes and loading it into a big box truck to be taken back to Austin. It was really amazing to see how well we communicated as a team now that we had spent 18 days on the river getting to know each other. We took a few group photos with the crew and then left for Memphis. That marked the end of our research cruise, and I definitely had mixed feelings towards the end. Part of me was happy to be sleeping in my own bed and not having to get up at 5:30am to get to the boat, but the other part realized how unique of an experience that was and knows that I will treasure my time on the M/V Strong for the rest of my life.
Well, it has been a very interesting couple of days on the boat. To start off with, the small compressor experienced some technical issues starting two days ago. One of the circuit boards in the control unit had a loose connection that would cause the safety on the compressor to trip and turn itself off. This was quite an unfortunate issue, because then we would quickly begin using the air in our reserve tanks and the pressure that we were firing at would drop rapidly from 2000psi to as low as 1800psi before we caught it. This is a bad thing because 1800psi releases a lower magnitude and lower frequency range of sound, which can mess with our data quality.
After diagnosing the problem as being the result of a connectivity problem within the compressor electronics, we took apart the computer and started playing around with the boards inside. We found that by pressing on the front of one of them, we were able to keep the compressor running. So, although we had ordered and received a new computer, we decided to find a way to keep the old one running as long as possible. To accomplish this, we used an intricate assortment of zipties and a small bundle of wire to push the board at the right point so that the necessary connection was made. Although it was a mildly rag-tag solution to the problem, it did the trick, shown by the fact that the compressor has run the past two days without any further issues. It will eventually die on us, but at that point we have a spare computer to replace it with, therefore we have little concern that the little compressor will be the limiting factor in us reaching our goal.
I was also really excited a couple of days ago, because I got assigned to change the oil in the small compressor. Now, this task requires removing the plug on the drain tube, funneling the waste oil into a bucket, replacing the plug, pouring oil into a tube at the top of the engine while checking an indicator at the bottom of the engine to see the oil level. Sufficed to say, this job would be best done with five hands and three eyes. Fortunately, one of the crewmates offered to help me without me having to ask, or else this would have been a total fiasco. That being said, I started off the oil change by wanging my hand against a bolt, while removing the drain plug, and tearing some skin off of a knuckle on my right hand (Hurray for war wounds!).
Shaking that off, we had squeezed the smallest funnel we had in between some of the pipes that were in front of the drain tube. To the funnel we had attached a hose to lead to bucket, but it was not quite long enough to trust that it would stay in the bucket at all times, which took up another hand. So we remove the plug and oil starts pouring into the funnel and into the bucket, as planned. Well, I take my eyes off the system for a second and when I look back I find that the hose is not in the bucket and the funnel is overflowing onto the pallet and deck! I grab rags to try and catch as much of the oil dripping onto the deck as possible, while David plugs the hole with his thumb to control how quickly the oil comes out. I make sure that the hose is still in the bucket and then pull back a second to look at the damage.
The rest of the job was pretty easy, not too many complications, and there was some clean up during and after, but all in all I would call the project a success with room for improvement next time around. It is really amazing to me how much you can learn about something just by trying it and making your own mistakes. Next time, I will tape the hose to the grating/lip of the bucket to keep it from moving, plug the drain hole to control to flow, and be more careful when opening the drain plug.
Otherwise, things have been going pretty smoothly, though (to explain the title of this blog post) the forecast for our area has been fairly bleak as of late; predicting that we will be over cast for the entire last week of our cruise. It was rainy again on Tuesday, yesterday was just cloudy and today is turning out beautifully! So, as a result, I say, “Weatherman, be damned!”, because we are going to have god weather simply because I will it to be so!
As I have been processing data and learning how to pick velocities, I have been more time looking at the preliminary data with the researchers and have been seeing some pretty cool structures on the preliminary CHIRP and seismic data from our array. Hopefully, we will have enough evidence to classify them as faults! More on that later, I must get back to sitting on the barge and watching the buoy!
My Geology professor, Dr. Brooks, once said to our class, “every time that you put equipment overboard, you have to accept that there is a chance that it will not be returned to you.” Now, I liked this phrase because it carries with it, the idea that marine field work, in particular, puts a lot of ‘wear and tear’ on the equipment we use, which is a testimony to the hostile environment that we work in. The basic point is, however, that a good portion of every research cruise is spent calibrating the equipment for a specific task at hand, maintaining the equipment to keep it from getting broken, and fixing equipment if it does happen to fail.
Fortunately, so far we have not lost any equipment on this cruise, ::knocks on wood::, but there has been some necessary maintenance, which has given me the opportunity to better acquainted with some of the equipment on board. Steffen is our resident Mr. Fix-It, so I tend to stick fairly close to his side when I know that things need to be fixed.
The biggest project, so far, that the team has tackled had to do with the ‘streamer’. So, the streamer is a line of hydrophones inside of a thick rubber tube that is filled with oil (not sure what type, somewhere between crude and canola), which performs two purposes: First, it allows for easier propagation of sound to the hydrophones (air is a terrible medium). Second, and more importantly, it makes the stream closer to neutrally buoyant so that it neither rides on the surface, nor scrapes the bottom. If the streamer is on the surface then our data becomes muddied with a lot of low frequency noise, but if it hangs too low, then there is a greater chance that it will catch on some debris floating within the water column.
So, our task was to make the streamer as close to neutrally buoyant as possible. To do this, however, we needed to know how deep the streamer was sitting in the water column, which was accomplished through the use of three transducers. A transducer, for those that do not know, is a device that measures and records the pressure that it is experiencing at a particular moment (e.g. once a minute) and then stores those values within itself. The pressure can then, with some compensations and correction, can be correlated to find the depth in the water that the transducer was while it was recording. This is really useful, because no wires are necessary, you just attach the transducer to the equipment where ever you want to know the depth and then take off the data at the end of the day.
We took a day of data, which showed that the streamer had an average of about 6 – 8 meters, which was far too deep. The optimal level would be around 1 – 2 meters. So, the next day we added a LOT of flotation along the streamer. Of course, this resulted in the streamer floating on the surface, which made for less than desirable data. The next day was spent taking the streamer in and out of the water to remove floats to the point where we saw the streamer LESS than before, but the data at the end of the day showed that it was still running shallow. Finally, on the third day, we removed a smidgen more floatation and the data showed that streamer was floating around 2 – 3 meters consistently, except whenever eddies suck a part of the streamer down to 10 meters (this another major worry of ours).
Similar customization had to occur for the electronic equipment used in the lab, the CHIRP, and the airgun, though we have persevered through them all. This just goes to show you that, even though a piece of equipment can be very advanced, it will probably still need to be modified and played with to make it work correctly for your purpose.
As for things breaking, however, we have been lucky, since nothing has completely died. So far we have had to perform an oil change on the big compressor and replace its desiccant filters. We also do basic checks for chaffing and tightness on the equipment constantly, so we can hopefully catch something before it goes bad. There have also been some electronic problems with the small compressor, it has a tendency to turn off randomly, and issues retaining enough pressure in the big tanks to support 2000psi at a shot every 6 or 7 seconds. Other than these small issues, however, things are going swimmingly. We are a couple miles short of where we should be, as a result of the rainstorm and working on the streamer, but otherwise we are collecting a lot of really good data and that is what really matters. I’ll post again soon!
Well, it has been quite a while since my last blog and some much has happened! So lets begin…
I was very sad to leave my fellow IRIS interns at orientation. I feel as though we had fallen into an awesome, dynamic group of individuals and, even though we all had come from different disciplines and backgrounds, we worked together to create a community that was bonded by a mutual desire and interest to learn about and work in the field of seismology and geophysics. But, alas, we all had to move on from that environment to our individual amazing opportunities, though I will continue to be excited about getting to see all of them at AGU in December.
Now, as to my amazing opportunity. I am not going to repeat my project description, because I have that on my profile, though I suggest you go read it for clarification on some of the stuff I am about to describe.
Other then the fact that my luggage was about 13 hours behind me, my travel into Memphis went smoothly (though I did have to run to both of my flights). A grad student that is working on the same project, Lei Guo (pictured below), picked me up from the airport, gave me a quick tour of the CERI, and then dropped me off at my apartment complex. After fighting with the electronic key to get into my room for the first time, my girlfriend arrived and we proceeded to outfit my room with all the essentials while taking a tour of the area. The weekend was nice and relaxing, giving me time to move in, meet my roommate, make dinner with Ado, and mentally prepare for work on Monday.
However, not much mental preparation was needed for work, because the first three days consisted of sorting out the bureaucratic issues with direct deposit, per diem pay for time in the field, computer account access at CERI, choosing which side of the cubicle Ado and I were going to choose (we decided on the inside section, but opposite sides so that there was not a wall between us. I will be interested to observe our productivity in this environment, but I think we both agree it was a good decision, though she has more light on her side. 😛), and long chats with our mentors clarifying exactly what we were going to be doing that summer.
I had a long talk with Beatrice the first day where she ran through a presentation she had prepared on the project to give to scientific communities. This helped to confirm a lot of my ideas about what I thought the project was about and provide me with the necessary background and language to be able to explain it to other people. She also talked with me about the 18 days that we were going to spend on the Mississippi collecting data and what I should pack for the excursion. So, over the next three days I packed, got my stuff in order, and generally prepared for the trip.
Thursday was setup day. I met the other researchers that would be working on the boat with me: Kirk MacIntosh and Steffen Saustrup, from University of Texas Institute for Geophysics (UTIG), and Brian Waldron, from the University of Memphis. We caravanned over to the United States Army Corps of Engineers (USACE) base in Ensley, Tennessee where a big truck packed full of our equipment was waiting for us in the lot (dropped off by Steffen and Kirk the day before). After passing through security, we went and met the boat on the dock where we unloaded all of our equipment using a forklift, pallet-jack, crane, and our bare hands. The rest of the day, about 6 hours worth, was occupied by untangling and running wires around the ship, setting up the electronics necessary to collect data, setting up the seismological equipment for easy deployment the next couple days, and getting lunch at an amazing barbeque restaurant in town. This day would/will mark my shortest work day for the next three weeks (about 10 hours).
Friday was our first day collecting day and was a pretty typical day on the river. I got up at 5:20am in order to be showered, packed up, and have eaten something by the time Brian picked me up from my apartment. The crew left at about 6:30am to get to the boat ramp so that the little boat, the Tiger Shark, could ferry us to the Strong. We get to the Strong, start drifting down river at about 2 mph, deploy all the equipment within 30 minutes of hopping aboard, and are recording by 8:00am, hopefully. After that, then next 7.5 hours are filled with keeping an eye on the equipment for pesky debris or unusual data anomalies, basking in the broiling sun, chatting up the crew, writing blogs (such as this one), reading, eating, and watching the GPS to see when we have covered 15 miles of river so that we can pack up and go sleep.
We usually finish collecting around 4:30 or 5:00pm, after which it is all hands on deck to pull in the equipment, save the collected data 37 times, and collect our stuff. If all goes well, we are off the boat 45 minutes after we stop collecting and we are headed to the closest dock to get a ride to the hotel where we will be spending the night. By the time we get to the hotel (or, in the case of the past two nights, our residences in Memphis) it is about 7:00pm, which means that we have been awake for about 14 hours at that point. The evenings include a shower, dinner, swimming, possibly some volleyball, any necessary internet activity, and bed (not necessarily in that order). Then, the cycle starts all over again…
Now, I do not want to give any of you the slightest idea that I am complaining about this arrangement, because I could not be happier. I get to work with my hands, listen to music, eat great food, and learn about seismology (and sometimes take a quick nap during the day, of which there is photographic evidence). I am loving every moment of this opportunity and I would not have it any other way.
Anyways, I took a lot of pictures of the Strong, the equipment, and some people to keep myself awake the other day, so I thought that I would append them to the end of this blog post for your entertainment. Until next time, ciao!
Yesterday was a very exciting day on the boat! To start the day off, I learned the basic signal processing procedure that we perform on all the data we bring in daily. It is really cool to work on a real set of data, be to look at the final stack and give a preemptive analysis of what that particular survey line could mean scientifically. Also, it gives me something to do every day that will take up an hour or two.
Anyways, as a result of the processing data and monitoring the equipment, I spent about two-thirds of my day in the lab, out of the sun. This was mildly depressing. So, when 1:30 swung around, I decided that I was going to switch positions with one of the people that were watching the streamer and airgun to make sure nothing got tangled up. When I got out there, however, it was cloudy so I veered of my course for the stern and headed for the kitchen where I made myself a cup of coffee and talked with the engineer, James, for a while.
When I got out of the kitchen, it was drizzling. Lei Guo had moved all of our valuables out of the elements and into the wench house on the Harvey Pete (the barge attached to the side of the Strong). Brian, Lei Guo, and I stood in the house and watched the rain, which slowly started to pick up. Seismic operations were shut down for the moment, because our safety became a more important factor than science (I know, shocking!).
Soon after, the lightning and thunder came and the fog set in. The lighting flashes lit up the entire sky, from being defused by the fog, and the thunder shook our boat’s foundations. Then the wind picked up, which took the big, fat droplets of rain, broke them apart, and flung them at us with great velocity. Everything in the house instantly became plastered with water if it was not behind something else. To top it all off, in the middle of all this, it started to hail. Coincidentally, and fortunately, this was the day that I decided to stuff my foul weather gear into my backpack to bring to the boat.
After about an hour or so, the storm passed us to the south and the sun emerged once more. Everyone was still onboard and uninjured, so we continued our acquisition for another 90 minutes before calling it a day. All in all, I got some good pictures (below) and an amazing movie (that will be on Facebook) of the storm, and we only fell short of our goal (of 15 miles per day) by a measly 1.4 miles.
In other notes, we added a transducer to the middle of the streamer yesterday, to see how deep it was sitting, and found that it was floating way too deep. As a result, we added flotation along the streamer today along with two extra transducers. Also, we saw some pretty cool stuff on the preliminary data from the hydrophones yesterday so I am very excited to process this data.
Also, I found out yesterday that Ado and I were hit by the same storm actually, since we just can’t help but do everything together. She was in Arkansas at the same time, as I am sure she will blog about 😛
Well, it is the last day of orientation and we are all attending a presentation from Michael about how to maximize our internship experience. The crux of the presentation was the idea of how people learn best and what ways someone can better an educational experience for themselves. A lot of how people learn has to do with what they want out of the experience they are a part of and, in the case of this internship, I have a number of goals for my experience:
Now that I have considered my goals for the summer, I need to make plans for how I will accomplish them over the course of the internship. To this end, I will be proactive in every aspect of my life. Tackling programming in Matlab and UNIX shells with gusto; Inserting myself into research situations (learning opportunities) whenever I can, even if it is not directly related to my project; meeting and making connections with people at the University of Memphis and aboard the M.V. Strong; pursuing conversations with collegues about the future after college; and forcing myself to get out and experience my new environment. I believe, with these goals and strategies in mind I will recieve an incomparable internship experience. Anyways, that's it for now, I will be posting more when I get to Memphis and while I'm on the boat!
P.S. Ado will NOT whoop my "tush" at chess!