To analyze our seismic data that we collected in Denali, we created a database of the information stored in the seismometers, and viewed it with Smart Pic, a
program that allowed us to analyze our data. We scrolled through data collected over two days to identify seismic events. We were then able to match our recorded earthquakes with data collected by the Alaska Volcano Observatory over the same period of time.What We Found:
In seismograph A, you can notice the varied arrival times for the P waves. In seismograph B, the arrival times for the P waves at different stations are much less varied. This difference occurs because the earthquake in seismograph A happened at a much shallower depth (0.0742 km) than the earthquake at seismograph B (105.2698 km). For example, the schematic picture C shows that seismic waves from an earthquake occurring at Location 1 would have to travel almost twice as far to get to Station D as it would to get to Station A. This accounts for the varied seismic wave arrival times. In contrast, seismic waves from an earthquake occurring at Location 2 would only have to travel a little bit farther to get to Station D than it would to get to Station A. D E
Both seismograph D and seismograph E have relatively high magnitudes (2.96 and 2.70 respectively). However, seismograph D shows much smaller amplitudes than seismograph E. This is because the earthquake in seismograph E occurred much closer to the stations (147 km) than the earthquake in seismograph D did (1577 km). The seismic waves that arrived at the stations were much stronger when they were coming from earthquake E than when they were coming from earthquake D and therefore, the amplitudes were higher for seismograph E. Earthquake F had a smaller magnitude (1.91) than both earthquakes D and E but because it occurred at a much closer distance to the stations (25 km), the amplitudes shown on the seismograph were much larger than those on seismographs D and E. Noise
In seismograph G, the scale for amplitude is set equal for all twelve sensors. This shows the amount of noise occurring at station ROOT that hindered our data. If there was a small earthquake or an earthquake that occurred further away, only stations HILL, ROCK, and SHVL would pick it up, but not ROOT because it would not be noticeable next to all the noise. Therefore, in order to notice an earthquake at station ROOT, it would have needed to be a higher magnitude or closer to the stations. Mystery Blobs:
While looking through our data, we observed sections of irregular, unexplained disturbances. These "mystery blobs" were clearly not earthquakes because they were only picked up by one station, HILL. Each mystery blob was almost identical to the other mystery blobs in length of duration, amplitude, and frequency. The first three mystery blobs arrived at eight minute intervals. The fourth blob however, occurred fourteen hours later, and the fifth followed eleven hours after that. Though we did not reach a decisive conclusion of the cause of the mystery blobs, our hypotheses consist of either a generator or another loud machine from a lodge near the station.
The highlighted section in the above seismogram shows a possible bus signal on SHVL along with one of the above mentioned mystery blobs.