• Jesus Rodriguez

Seismological Field Work

This week Mariya and I finally got around to doing some significant field work. We spent the last three days moving down the Pacific strip of Costa Rica taking a look at ICE's seismological stations. After inspecting four active stations and two possible future locations, we had a clearer picture of the data we were working with. For example, the station LLNJ (located in Naranjito) is placed above ground in a telecommunication relay station, so within the building there is a lot of noise. The location is practical because it is private, already owned by ICE, and it facilitates live data transmission, however, the fact that it is above ground makes it less reliable and the room is terribly noisy due to all the machines operating inside. At the seismology office, every time we would work with the station LLNJ we would get frustrated since picking it would often be difficult, now we understand why it always gave us a hard time finding the P and S waves. Seeing the prospective areas where we would plant our future seismometers was also a delightful experience; Mariya and I were trying to anticipate problems we might encounter as well sources of noise or error. We are super excited to see our equipment finally come out of customs.



Speaking of getting our equipment out of customs... it all arrived! We found out on Wednesday night that we would be able to take the equipment out Thursday morning. By Thursday afternoon all six of us had cancelled our plans with our mentors to test out all the pieces that arrived. In 11 large boxes we found 6 seismometers with control boxes, 6 Data Acquisition Systems (DAS), 6 Samlex (which provide the voltage that goes into the DAS), 7 GPSs, and a slew of cables and wires to make each doo-hickey connect to the other dinga-mabob. It took us about 30 minutes to count each item and double check our list to be sure that nothing was missing.


After a successful double check and triple check, we began testing the systems and preparing things for a night of data acquisition. The night began in a promising way; everything connected just fine, no wires were split, no excessive manipulation of equipment had to be undergone, nothing could possibly go wrong on a such long-awaited day. But, in order for the equipment to work as intended, the DAS for each system has to be properly configured and the software has to understand what exactly its job will be for the next 6 months. For example, it needs to know how to save the data; does it save as SINE waves or Steps or other data types? It also needs to know how many samples it will take per second and where to save that info once its recorded. The system also has to be configured so that it works with the right model of seismometer, GPS, and DAS. In reality, there is a web of connections that has to be modified and configured appropriately and there are minor details that must be taken into account. How will we know if the system stops recording accurately? How much error is in our equipment? Or what if the time in the DAS is slightly incorrect? We have to program each and every little element. We knew that the process of setting everything up would be long and meticulous, but we had no idea that the machines would try to fight us at every step of the way...


We ran into issues almost immediately. After maybe four steps into the 15 step process, all three of the IPods we were using to communicate with the DAS starting having problems, in three different ways. One couldn't save TO the DAS the other couldn't load FROM the DAS, and the last would crash at random moments. Then the GPS would have a hard time locking, or if they did lock on they would then fall asleep, or if they didn't fall asleep, two side-by-side GPSs would give different altitude readings. It was a mess to say the least, but we knew how to solve it. Even though we criss-crossed all the wires, we stretched th wires each and every way just so that the GPS could extend outside the room and pick up more than 3 near by satellites. That solved our GPS problem. However, although we started with three IPods to configure everything, we only used one, which made the process unjustly long.



After about 7 very patient hours we were able to program and configure all six stations. All that is left now is to allow them to record overnight so that we can feel safe in all the work we did today. To be fair, it was long, annoying, stressful, and the whole process was a great test in patience, BUT it was rewarding and this was exactly what we've been waiting for for about 4 weeks. Despite the frustration, I'm ecstatic to see everything unfold in exactly this way.


The FINAL product


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