During an active source experiment near Mooring, TN, a swarm of microseisms with ground motions equivalent to earthquakes of M_L -1, were detected in more than half of the seismograms in the array. The array was positioned directly over the Reelfoot fault zone on an afternoon in November of 2006. Since then, 19 broadband sensors have been deployed near the area as these occurrences merit further investigation. My part of the project includes the analysis of this data. I will be writing code that will filter the data and perform frequency and wavenumber analysis of the data in an attempt to discover whether these events were a one time occurrence or if they are evidence that there are active fault processes in the seismic zone.
Well, it seems that I am the first to finish this summer. I finished a few days ago and then Katie and I begun the long drive home. Overall, Chuck and I are happy with the summer. We got a lot done and I have a few different ideas to think about for my abstract. I really enjoyed the summer and I really liked my project. I havnt been able to work on it for the past few days and to be honest, I miss looking at my squiggly lines. But I am glad to say that because now know that I really want to study seismology. It was a great summer and a great experience and I look forward to seeing everyone in December.
Well, I only have three weeks left on my project. A bit intimidating considering the fact that there is still much to do. After finishing the frequency/wavenumber analysis, I wrote a GUI that allows me to look at the time intervals that looked interesting from the initial analysis. So currently that is what I am working on. I made a short visit to my original goals, and again, there is still much to do. I wanted experience with ProMax but it looks like I will not have time. I need to concentrate on my project and not worry about other things. Besides, it seems that the IT guy here is on vacation so they havnt even started working with ProMax. I will have to catch up with Xenia later today to find out what the latest news is there.
On a different note, Katie and I had our first real southern thunderstorm last night. The news last night said it wouldn't hit the Memphis area at all, but come midnight or so, we were woken up by very large and loud crashes of thunder and lightening. We flipped on the news and it was reported that at least 100 bolts had made contact with the ground. So it was pretty spectacular to see this storm. It continued till about 10 this morning. And the news is full of flash floods warnings throughout the area. So it was pretty cool so see this type of storm.
Well, in the past few days, I have been able to get through about a month's worth of date, which is good and it looks promising. In the original paper that Chuck and Beatrice write when they first detected these small earthquakes, they estimated that the area has a seismicity rate of 257-1029 events per hour. Which amounts to 6168-24696 events per day and I am finding events with very low slowness with a rate of anywhere from 5000 to about 10000 events per day. We are not sure if they are official earthquakes, but they have a slowness that is much smaller than the norm for the area, so who knows, maybe we have found something. So basically right now I am going through data and putting together presentations for Chuck so he knows what we have found so far. It has been pretty exciting the past few days here because my code is finally working and not only is it working, but it works correctly and efficiently. Other than that, had a fun 4th, we didnt do much. We went swimming and watched the fireworks and that is about it. But I love spending time with my wife and daughter so it is all good.
Well, last week was a good week. I have pretty much all the code done that I need to write and I am able to pull data in and start working with it. And I was excited when I was able to implement some of the things I learned in one of my numerical analysis class. As of last Tuesday I had all the code written and when I ran the code, it took about 400 secs to analysis 100 secs worth of data, so as you can see, it would take along time to go through 14 months of data (or however much we have right not). So I spent the next two days rewriting the code, hoping that I would make it more efficient and my efforts seemed to pay off, but I brought the computation time way down. So this week I will be working on the data. Chuck wrote a program that makes synthetic data so what I will be doing is creating a bunch of waves, superposition them and run that synthetic data through my code to see what those parameters would produce. I then have a good idea of what I should see and then I can go through the data to see if that is what actually happens. My goal is to get through at least a month or two of data this week.
I also had my first field day on Friday. Three of the 19 monitors in our array were flooded so we went out there and replaced the data acquisition equipment and had to raise the action packer boxes so they wouldn't flood again. The array is about 2.5 hours away on a soy bean field and it only took us about 1.5 hours to change everything. So we spent more time driving than we did actually working, but that is okay, it was pretty hot and I was done after almost 2 hours outside. We than went and had lunch and I had catfish for the first time, and it was amazing. I love the food here and I will miss the food and the people when this is over.
As for the world cup, I apologize, I haven't really been following along. It seems that everyone else in the world is, but my wife and I are not. I hope you all can forgive me considering I have nothing to contribute about the world cup on the blog nor on facebook. I usually go have lunch with my wife and go sightseeing and go out to dinner with her and the little one in the evenings. Again, I apologize for my lack of enthusiasm. Good luck all and see you in December.
Well, much progress has been made during week two. Chuck returned home from Salt Lake last Monday and we sat down for a little while a talked about a lot of things. I had been working through some of his code and some code he downloaded from a PhD student in Alaska and it was my job to get both codes to work, and then mess the two codes. I got through both codes and got both of them working, but on Tuesday, I discovered that Alaska's code does not do what we thought/needed it to do. So we had to scrap that idea. Plan B for the project was to get together with Heather, another research professor here and she has a few matlab packages that may work. What we are trying to do is pull data from our Antelope database into Matlab so we can work with it. Currently, we pull it from Antelope into SAC and then from SAC into Matlab. This is a perfectly valid way of doing things, but it is inefficient with time and memory. For example, one day of data has over 3 million data points for just one component of one station. So you can imagine how much data we have for 19 stations with three components each. So main goal at this time, go straight from Antelope into Matlab.
So on Tuesday we talked with Heather and she gave me the Matlab environment and scripts that accomplish this and we found that Antelope only works in Chuck's old office. So instead of trying to get the different programs to work on the graduate student computers, Chuck just moved me into his old office. Which is nice. I now have a 24" Mac with a second 24" monitor, almost a terabytes of memory to work with and like 4 gigs of ram. So needless to say, I am enjoying my new surroundings. (In case you are wondering, I was working on very old Sun computers that were very slow).
By Wednesday I figured out the Matlab scripts (with the help of Heather). So Thursday and Friday I spent the day playing with data and become familiar with all the scripts, their capabilities and limitations. I wrote code that allows me to pull data from almost any time window from any component of any station. Though I did run into a tiny problem that Chuck and I dont know how to handle yet. For some reason we cant pull data from two 'rows'. In other words, if we want data from the end of day 1 and the beginning of day 2, we cant because we day is a new row. Normally this would not be a big deal, but what if there is an event that starts at the end of day 1 and goes through the beginning of day 2? We wont be able to look at that event in a continuous manner. So we are dealing with that right now and we will see what happens.
So goals for today/this week is to be able to take data from Antelope and plug it into his code which will help use do some frequency/wavenumber analysis. Hopefully I will be successful so that we can start finding these little earthquake and find out their origins.
Well, last week I felt was successful, but at the sometime not so successful. I am currently working on taking data from our broadband array that is in SAC and uploading it into Matlab. From there my advisor has written an analysis code that we will use to look for and locate our anomalies but here is the part where I get stuck. I am learning a great deal about SAC and I can easily get SAC data into Matlab, I just can't get his code to work. There is talk of the need to write my own code, and if that is the case, I will be very busy for the next few weeks writing code. And then I can finally figure out where these microearthquakes are coming from. So on the Monday morning of week two, I will once again begin my matlab adventure and hopefully I will see more success this week than last.
Well, Beatice gave a pretty good introduction to the project I will be working on. If everyone remembers, she mentioned that one day during an active survey, they found a swarm of microearthquakes. At this time, there is no known reason for these earthquakes. Therefore, my project this summer is to figure out what is going on. After the initial detection of these events, a broadband array was deployed and has been recording data for the past year or so. We will be combing through the data trying to determine if these events were merely coincidence or if they are occurring at any regular intervals. Therefore, my biggest goal is to discover just that. I also have some smaller, more personal goals. I would like to learn SAC and GMT and also continue to learn Matlab better. Also, if I have the chance, I want to work with ProMax and try to learn as much of the software as I can.
Apparently I forgot to put sunscreen on my face for the hike yesterday so as a result my face is sunburnt. It hurts and it is dry and chapped. Just in case anyone wanted to know.
By the way, for those of you that aren't really into math, infinity divided by infinity is not 1!!!!!!
Well first, I would like more math. The geology is fun, but I like math. I have enjoyed the field trips and the installation of the broadband network was very fun and very insight full. I am looking forward to working in Memphis, even if I didn't get the project I wanted (cough cough). But I am excited. It is a fun city with lots of things to do and I hope to learn a lot about the theory and application of seismology. I do have feelings of nervousness because I do not know what to expect, but that is all part of the adventure.