Gillian Goldhagen

August 2nd, 2016

This week I am working on finishing up my figures and quickly learning the basics of waveform matching technique. I will also have to try to finish my poster and write a paper on my research. If I don't get everything done I can still work while I am back home or even during the semester, however I would prefer getting everything done now. I completed two new figures today in an attempt to tie in another Chinese Academy of Sciences array. Z8 however does not show preliminary signs of remote triggering so I will probably not go further into processing the data. My two new figures show the location of Z8 and a quick graph to showcase how unlikely the presence of remote triggering is. Even though I already started doing a lot to my poster I am happy to find a way to fit in my newest figures. With all of the work I have been doing to finish up it is becoming more and more of a reality that my time in Georgia will be ending soon. I will miss the sun and city although probably not the humidity.

The summer was a huge learning experience for me. I came in with very little knowledge of coding, remote triggering, and China. At the end I can now say I have a much better grasp on coding as a whole and especially with GMT and SAC. I have also learned so much about remote triggering and why everything that I do to process the data helps to detect remotely triggered earthquakes verses other earthquakes from farther away. I also got to experience and learn a lot about China after living there for a month. I kind of miss using chopsticks and learning more about their history and culture. I would definitely say I accomplished all of my goals from the beginning of the summer. I am much more familiar with coding than I was at the beginning and think I have a true understanding of my research. I am glad that the summer went as i had hoped it would and I learned so much. I came into this summer terrified that I wouldn't learn anything and would constantly be stumbling around without a clue. I learned a lot about passive seismic and the programs used to interpret waveforms. I spent weeks going through station data by hand trying to find evidence of local earthquakes. I have a much better understanding of SAC and how to use it. I also learned about important processes like taking the envelope of my data and finding p and s waves that way, and the STA/LTA function and how that works. This experience has been very different from my previous experiences with geophysics. This project has made me want to learn more about seismically in a whole.

Working the way I have the past two months has also gotten me excited for going to grad school. I like the idea of having a clear project and steadily working towards a goal or discovery. I also liked the freedom of not being in such a structured classroom environment. This internship has certainly helped to assuage some of my fears of grad school. I feel like I am more prepared for my future and more experienced overall after this summer.

August 2nd, 2016

Week 8 was spent mostly writing my abstract and updating or creating more figures to use for my AGU poster. I am very happy that I managed to submit my abstract by the early deadline. Since I only have one week left this means I can focus more on my poster and paper this last week. My abstract had to go through editing from every coauthor as well as a couple of my friends and my fellow intern Clara before it was ready to be submitted. I ended up submitting it with about 30 minutes to spare for the midnight deadline. I am very thankful to everyone that helped with my editing process. I knew what I wanted to say for my abstract but sometimes struggled to find the perfect wording to get my point across. Multiple rounds of editing really helped to fine tune everything.

This week I also managed to put together 6 total figures for my poster. I am hoping to get the majority of my work done before I leave since i will be starting new research in the fall up at Binghamton. After I organized my figures I had a list of things I had to go through and fine tune with them. On some I had to add features, others I needed to recreate in GMT. Overall, I am happy with the entire process which will hopefully ensure my figures are properly explaining my research.

July 22nd, 2016

This week I tried to widen my Sta/Lta window. When I did that, I got a much nicer beta value which suggested there is in fact an increase of seismicity after the main shock in the Tanlu fault zone. Of course my data only runs through this fault zone at the bottom of my array. After you pass station 30 or so, you are too far away to see the effects of the fault. Knowing this I have been mainly focusing on station 8 through 12. After widening my window for my two hours of data before and after the Wenchuan earthquake, I decided to expand into a longer time window overall. I went through by hand and picked events showing a p and s wave on station 11. I did this while still looking at station 9 through 12 to ensure that any events picked showed up on all of the stations, not just one. from there I calculated my own beta value. Overall the values have seemed very promising. The seismicity in the fault zone seems to pick up after the main shock passes, however this is not evident immediately after the wave travels through but a few seconds after. 

This week I also managed to make some figures that can probably be used for my AGU poster and updated my original GMT map. My map now shows other network stations near my network and background seismicity 3 days before and after the main shock. I also created a second map to just focus on background seismicity locations from 1970 to 2012. 

Mostly towards the end of the week my focus was on downloading more data. In china I had only managed to download 1 day of data for my stations. While in America, and with much better Wi-Fi, I found it much easier to download a week before and after my earthquake. I need the data now so I can eventually go through it with the match waveform technique. We have been having trouble with locating events that have been large enough for my stations to pick up nearby. Next week we will likely move on to a new technique of finding events so we can use the match waveform process. 

Thankfully for this week, I have had a grad student, Chenyu Li here to help me out. While I feel like I have learned exponentially more about coding since coming here there are still plenty of times when I struggle to figure out the correct code to perform the action I want to do. Since my time at Georgia Tech is so short It is helpful having someone here to show me the ropes as I learn more about match waveforms and its very coding intensive process. 

In the beginning I knew almost nothing about SAC and GMT but after being told to explore my data on SAC at my own pace and with the help of tutorials I think I have a much stronger idea of what I can do. GMT is something that I grasped the best since I was able to learn it by adapting Clara Daniels old code. I am now much more confident when I have to add something to my map because I feel like I understand GMT's coding so much more. Luckily Clara Daniels and Chenyu Li have been great helps and have both managed to help me expand my knowledge over this summer. Hopefully I can learn even more in the weeks I have left. 

Below are my four figures that I worked the most on this week. The code for the first figure was given to me by Chenyu. The blue dotted line are my earthquake picks. It shows station 9 through 11 and a spectrogram from station 11 at the bottom. I need to work some more on this figure to take out some of my picks that are actually from aftershocks at the main shock's epicenter.  The second figure is a result of preforming an STA/LTA process on station 11. The beta statistic shown is very promising, since usually a number above 2 indicates an increase in seismicity. The window used was 5km/s through 1 km/s after the main shock with a total of 10 hours shown overall. The last two images are my maps discussed above. 

July 18th, 2016

I spent the following week back in America getting readjusted to the time zone and moved into my housing at Georgia Tech. I was a little sad that I wasn't able to be back in New York for a couple days since I really miss New York pizza. Georgia pizza just isn't the same. I was however able to fly home briefly this weekend to see my family, eat pizza, and distribute all the gifts I picked up in China.

As for research I started going through my waveforms on SAC and counting individual events. I did this for 6 stations out of 60. I then ran an STA/LTA where the computer picked the waveforms for me. This wasn't fool proof since it counted every peak, including noise. At first I got numbers that did not look so promising but they slowly started looking better after I widened the parameters. Overall it is looking like there is a slight increase in seismicity after the mainshock traveled over the fault line at the bottom portion of my array. My next step is to go back to picking by hand, this time with multiple channels at once to try and calculate a beta statistic by hand. The beta statistic is a number based off of the events inside a certain time period and the events total. A larger beta statistic after the main shock goes through indicates an increase of seismicity, usually attributed to the main earthquake. If there is a larger amount of seismicity at the areas near the fault then this helps to prove that induced seismicity is more likely to occur near fault lines. This can help us to better understand the stresses of certain areas and eventually help us get closer to predicting earthquakes. After I finish picking by hand and calculating new beta-values I will probably try a different computerized technique of matching waveforms. I will learn more about that as the week goes on.

On friday we had yet another presentation, this time for the people at Georgia Tech to understand what Clara and I are both working on. This let us meet more people and learn about other projects going on this summer. These meetings will become a weekly fixture to keep everyone up to date on progress and research being done throughout the rest of the summer.

Being in Georgia is very interesting after spending so much time in China with Clara. Clara and I still live in the same appartment complex but nolonger share a room. It is weird not being together 24 hours a day. It is nice that everything is in english but I definitly apprciate my own state of New York.

July 12th, 2016

This week was the fifth week of our being in China. The fifth and our last. We ended our fourth week with going on tours around Beijing during the weekend, which we shifted to Friday and Saturday in order to avoid the crowds. In return Sunday through Tuesday was spent in a mad rush of getting things done in preparation of giving a presentation for CAS and getting things done before leaving for America. Clara and I both gave a presentation of the subject we were studying, including a brief summary of some previous related studies done by others, our work we completed at CAS and our next steps. We then presented in front of our local Chinese mentors and anyone that wanted to come. It was a good way to both learn more about my subject, show my progress and my goals, and practice presenting in front of people. People were also able to ask questions after which was also good practice for us and a good test to ensure we knew what we were talking about.

I set a personal goal to complete my GMT map before I left China. This was both to ensure I had something to work towards and more practically because I was working on a remote server that couldn’t be accessed outside of CAS without downloading a couple directories and modifying some of the code. I almost reached my goal. I completed my map and classified all of my stations however I ran out of time to color code my stations on my map to my preliminary findings from looking through the SAC data. Luckily all the correct directories got copied and it should be relatively easy to start back up again on American soil.

A figure that would best represent my data so far would be the spectrogram below, it shows both my method of downloading the data and also the high pass filter used to detect the earthquakes. I go through spectrograms and SAC files of each station trying to find evidence of p and s waves.

Being in China for a month was definitely a life altering experience, it let me experience working in another country where I don’t speak the language and definitely stand out from the locals. I learned tons of new skills, such as learning how to use SAC, new applications for matlab and learning GMT, as well as how to work in different environments and use chopsticks like a pro.

I will definitely miss the people, the wonderful office they gave us, and the Beijing subway system which was very easy to understand and explore.

For the second half of the week we were actually given a couple of days off, Clara and I utilized those days to explore a new city in the south of China called Guilin. There, we had a wonderful time surrounded by Karst mountains and taking a cruise on the Lee River. We enjoyed our time in the country experiencing a whole new side of Chinese life. While our brief break was nice I will be happy to get back into the routine of work back in America. I still have a lot to do before the end of the summer. 

June 30th, 2016

This week I focused mostly on GMT and creating a map of my study region. I did this by borrowing an old code of Clara's and learning the different pieces of it to slowly adapt it and add to it for my own study area. After doing this I cut out the pieces I understood and knew I needed and created a new version almost entirely my own. From there I added topography, fault lines, my stations, and a smaller map of China in the corner. I feel like I now have a much better understanding of GMT after the hours of looking up code and GMT tutorials online. I have also been slowly going through my stations and marking which stations show promise of remote triggering. Eventually I will add colors to my map to show which stations had remotely triggered earthquakes and which did not. It will be interesting to see how this matches up with the fault line locations. 

In between learning GMT, I have also managed to go site seeing at the Great Wall of China, the views were amazing and it was definitely an experience I will never forget. We went to a much less crowded section of the Wall where we could fully enjoy the beauty of the wall and the surrounding mountains. According to Clara's phone we walked around 6 miles, up 72 flights of stairs and around 12,500 steps. It was amazing, some parts were a bit harder to climb than others due to their varying steepness and when they were last repaired. The actual steps on the wall were uneven which I assume was done on purpose to force intruders to pay attention to walking as opposed to attacking. We managed to walk along a section that had not been repaired at all and it was very cool to walk on a piece of original history. Both the ruins of the towers and the renovated tours and wall were amazing to see. I loved the entire experience and could have spent hours more climbing the wall. 

One thing that is different about China is how they do laundry. They have a washing machine available in our dorm but no dryer. Everyone in China hangs their clothes to dry. This is a little harder for us since we don't have hangers but we do have a multitude of hooks on almost every surface in our room. It is an amusing sight to enter our room after laundry day. However, one thing I never gave much thought to is the full purpose of a dryer, not only does it dry wet clothes it also removes lint and fuzz. After our first day doing laundry we made the unfortunate discovery that our blankets that we had been provided create a lot of fuzz, blue fuzz, absolutely everywhere. After washing it it now sheds non-stop and with our lack of a dryer we officially have blue fuzz everywhere with no real way to get rid of it. Most of our clothes are covered, especially if they were unfortunate enough to have been in that first wash with the blue blankets. Our beds and pillows and most of our room is also covered in the fuzz. There isn’t a single morning I wake up without discovering pieces of blue in my hair. I have never missed a washing machine so much, baring a lint roller there is no real way to get the fuzz off our clothing so for now we live in a slight cloud of blue. 

One interesting thing I have found is that overall people are the same. No matter where we are Clara and I stand out, babies stare at us. It is quite common for Clara and I to go somewhere and get offered coffee, because naturally all Americans love coffee. This is slightly more amusing to us since neither Clara or I drink coffee and instead prefer tea. Still the very subtitle cultural assumptions are made all the time. I firmly believe that if the situations were reversed and a Chinese group of students came to America they would constantly be offered tea so rather than a difference I found a surprising similarity that I think transcends all cultures. 

One more difference around here other than the food, the language and the culture obviously, is the love for umbrellas. Whether it is raining or too sunny the umbrellas are out. As a culture we have learned that the Chinese idea of beauty is to be very pale, even going as far as to use bleaching cream on their skin. Because of this when it is sunny umbrellas come out to shield them from the sun just as often as they are out on a rainy day. They also have all types of umbrellas, from ordinary ones like ours to beautiful ones that sparkle in the sun. This is especially strange for us since in the US most girls love to be tan while here they go through great lengths to be as pale as possible. 

Clara and I of course don't worry so much about that since we are getting pale without an umbrella's help just doing our research. 

June 24th, 2016

I am definitely getting a better understanding of my research question, I didn't fully grasp this fact until I was asked to create the elevator speech for this week’s blog assignment. I now think I have a full understanding of the science behind why what I am doing would work to find remotely triggered earthquakes. Since the earth filters out high frequency over time and distance naturally I am looking in areas farther away from the original earthquake to try and find higher frequencies. These high frequencies don't come from the original earthquake but from the area of the seismographs indicating a new earthquake was triggered due to the waves of the first earthquake passing through. So far I have been tasked with looking through each spectrogram that I have created to try and find areas of interest. If I think that I have found a high frequency signal that looks promising I then plot it on SAC and see if the waveform has a clear p, s, and surface wave. Some of the areas I look at end up being noise or some other signal but I have found some stations that look promising. Doing the elevator speech of my topic helped me realize that I had a firmer grasp on my task than I had originally thought. Elevator speeches are useful for understanding the big picture of your research and being able to quickly explain the basics of your task. Sometimes it is easy to get lost in the smaller details and forget what the main purpose of your research is. Being able to boil your research down is a good way to show and share your understanding of the project at hand. 

Over the past week in-between site seeing, looking at waveforms, and attempting at creating a basic map of my area on GMT I have been attending different talks here at the CAS campus. They have had a couple english speaking professors here to talk about what they do. I love going to the talks because I find that I have a very general knowledge of geophysics and geology, with these talks I gain insight into different specialties and specifics while still remaining general enough for me to understand it and ask questions. I am happy to say that this week I have learned more about Mars (like the fact that Mars can have volcanos but no evidence of tectonics), subduction zones (specifically in the Caribbean and Mediterranean) and repeating earthquakes as well as earthquake prediction. I love being able to learn more and expand my knowledge of geophysics. Most of these professors have drawn me into their topics very well proving that they would be capable of giving excellent elevator talks. If a speaker knows their topic and explains it well enough I am better able to understand and learn from them. 

As for getting along in a foreign country; so far everyone has been wonderful and very accommodating of Clara and I not being able to speak the language. The language barrier can be a hindrance but if everyone is patient we can usually work out an understanding. Sometimes though we revert to needing hand signals to properly understand what people are trying to say. We are trying our best to learn the differences in culture to not be accidentally rude. I have found that sometimes people think things are common sense and forget to warn us about certain things until someone catches us doing it wrong. We had an incident like that when we did not realize the hot water tap was not a sink and that we had accidentally flooded the room. 

We have so far gone to visit the forbidden city (which was closed so we walked around the inside of the wall and took pictures) and the Ming Tombs. Both had beautiful architecture and a lot of history. The subway ride to get to the forbidden city was extremely easy to understand so it was slightly confusing when the forbidden city was a little less clear. We found ourselves confused on where to go and even how to leave since there was a lot less direction. I think we would have probably had an easier time if we had gotten a tour, or even if we had decided to visit on a day the museum was actually open. It was a little sad to be around all that history and not be able to understand the full story of it. Besides that, we are having a lot of fun exploring the city at our own pace, and we managed to learn a lot about the Ming dynasty during our tour of the Tombs and anti-corruption museum. 

June 16th, 2016

I am currently downloading data from a network of seismometers arranged in a straight line across a northwest corner of China. There are 53 seismometeres, 153 channels, spaced a couple of kilometers apart. I am looking into the time area around the 2008 Wenchuan earthquake in China to see if I can find evidence of earthquakes being triggered in the area as a reaction to the major earthquake.

The data shows some evidence of clipping and some of the channels did not record properly but overall the data looks good. I am currently trying to download and plot data on spectrograms in matlab, the process is proving to be very slow due to the internet constantly cutting out and disrupting my download. I am starting out by saving these plots in pdf form and downloading the SAC data. After the data is downloaded I will plot the SAC files to see what the data shows. These seismometers for this time has only recently become available so I should be one of the first people looking at it.

I should be downloading data from the 2nd of May 2008 to the 1st of July 2008 to get 10 days before the quake and 20 days after but the wifi has not help up long enough for me to do so. At present the longest time period I have managed to download is 5 days after the initial quake and even that much has proven difficult.

I think it is very important for me to be able to understand the research problems. Coming into this project I knew very little about remotley triggered earthquakes besides what was common sense. On the second day of being here I was able to sit through a lecture on the topic and found that the science behind it was fascinating. Understanding the process was a little harder for me but understanding the overall problem is definitly a key part that needs to be fully understood first. Without fully knowing what I am trying to get from the data it would be impossible to carry out the process to get there.

Since I came in with very little prior knowledge it is especially important to me that I get a full understanding of the problem I am trying to find the answer to. To remedy this Dr. Peng has luckily given me research papers to read so I can become more familiar with the topic and what I am looking for to eventually hope to find the existance of remote triggering in this particular area from the 2008 earthquake.

I figured at the end of my post I should also add in a little about my time in China and how we are adusting. Luckily Clara and I are not suffering from jetlag since we decided not to sleep on the plane here and basically did the equivelent of hard reseting our bodies to the new time zone (A full 12 hours different from my normal time zone in New York). Each day we have lunch in the dining hall here at the institute and for dinner we have been exploring the restaraunts in the area. It is a little harder for me with my eating habits, and the fact I don't really like spicy food. I think it would have been easier if we had a kitchen available that we could buy and cook food to our own liking and only go to restaraunts to sample the local food a couple times a week rather than everyday. Around here often even the simplist food is very spicy and I think I'm definitly starting to miss pizza. 

Clara and I have plans to work through this weekend in favor of using Monday and Wednesday for siteseeing. We were told it was better to go during the week when it would be less crowded. We got metro cards and plan to try and make our way to the summer palace Monday. On Wednesday we will try to tag along with some of the scientists here who are taking a day trip to a more rural area of China. For the past two weeks we have mostly stuck to the surrounding area due to us coming in during a holiday and trying to avoid those crowds. Monday will be our first time on public transportation and leaving the surrounding three blocks.  

June 10th, 2016

Made it to China!!! and after 6 days we finally have our luggage, (which was lost when our plane was delayed making us catch the next plane 24 hours later in Seattle). 

Now I can fully focus on work, The first few days have consisted mostly of my completly tutorials but once I finish that I will need to repeat my actions from the tutorials with my actual data. It will be interesting to see how well I can translate the two.

I have a couple of goals to accomplish before the end of the summer:

  -My first goal: to get better aquanted with coding, become used to using certain commands so I am nolonger second guessing what I type

  -My second goal: is to experinece more of the Chinese culture while I am here, I hope to be able to explore and learn more about my surroundings when I am not working.

  -My third goal: to learn the proper way to process passive source seismic data and to learn more about remotley triggered earthquakes or tremors. 

All of these goals seem managable and with any luck I will have accomplished them all before I leave this summer. For now I am mostly focusing on learning with my tutorials and getting used to living in China. 

June 3rd, 2016

Trial blog post;

Trying to pick up coding fast and getting an review of an overview of geophysics.

So far the coding has been interesting if not completley successful, it will probably take more time than this one week.