All three stations are located in the seismically quiet New England region of the United States. R4989 is located in the University of Maine seismic vault in Orono, ME, on large glacial boulder pavement close to bedrock. R35E7, the station in Poland, ME, is located on the carapace of a glacial drumlin, likely within two meters of bedrock. RCB43 is located on fluvial terrace and glacial Lake Bascom sediments, likely ~2-4m from bedrock. Stations further from bedrock are much more sensitive to surface environmental noise like passing vehicles. Small seismic events have been observed nearby, and major earthquake events (magnitude 6.5+) from around the world are detected at all of these stations.
Availability plot for today, 2018/06/22
Plots are updated every other minute. Two stations are located in basements about 50-100 feet from residential streets. Vehicles driving by at speed account for a large portion of the spikes seen in the data. Other potential sources of noise include washer/dryer vibration, indoor foot traffic, and cars entering and exiting the driveway. In the winter, snowplow noise may be the largest source of vibration detected at these stations on a given day. During the warmer months, lawnmower noise may be evident as well. The anthropogenic noise sources generally fall in the 10-20Hz range of the frequency spectrum as observed at this station. Earthquakes, should they be detected, will likely cover a larger (and lower) portion of the observable spectrum than the rest of the noise sources.
Plots rendered at 2018/06/22 10:57:35 UTC.
Page loaded at 2018/06/22 10:58:30 UTC.
Plot selectionR4989 - Orono, Maine || R35E7 - Poland, Maine || RCB43 - Williamstown, Massachusetts
Currently viewing plots for: AM.R4989.00.SHZ
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Spectrogram of the past five minutes (unfiltered):A plot of energy density at given frequencies over time. Spectrogram z-axis (color) units are dimensionless.
0.7 - 2 Hz bandpass:
Helicorder plot since UTC 0000hrs:
0.7 - 2 Hz bandpass helicorder plot (can detect P waves from large, faraway earthquakes):
These plots are made with a combination of ObsPy and Matplotlib formatting. The spectrogram above scales based on the density of energy at the given frequency, based on a moving window with an overlap of 0.9/1. The helicorder plot resets every day at 0000hrs UTC. Traces plotted on the helicorder are scaled down by 800 and 70 respectively for readability, although this is subject to change as I get more familiar with the signatures of environmental noise that the geophone picks up.
RCB43 was moved to Williamstown, MA On December 21, 2017. Prior to that, it was located in West Poland, ME for the summer and fall of 2017, and Greenwich, CT, near the downtown area before that. On December 17, 2017, it was replaced in West Poland by R35E7, a model with a newer digitizer board and three orthogonal geophone axes instead of one.
R4989 replaced R06AC, which was flooded on January 15, 2018. R4989 has moved locations but is now located in the University of Maine seismic vault in Orono, ME, alongside the NE.ORNO station operated by the New England Seismic Network (NESN). NE.ORNO is operational but has not sent data to NESN for several years because of network hardware incompatibility.