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Anthropogenic (human-caused) seismic noise results from vehicle traffic, machinery, and other sources. Following #coronavirus lockdowns, anthropogenic noise on urban seismometers in Europe has decreased.... 1/? https://www.nature.com/articles/d41586-020-00965-x
I decided to see if this phenomenon has occurred in the Washington DC area, which has been under regional stay-at-home orders for approximately a week now. 2/?
First up, a plot of seismic energy recorded at a USGS Netquakes station in Reston VA - very close to DC's busiest international airport. 3/?
Reston is just off the Dulles toll road, the main route from DC to the airport, so airport traffic probably contributes significantly to the noise on this station. 4/?
Normally, the biggest noise day on this seismometer is Friday (the gray bars show weekends), when people typically head out of town for the weekend. Last week the trend reversed, with Friday being the quietest day of the week. 5/?
Next up, here's a similar plot for a USGS Netquakes station located at the US Capitol building, right at the end of the National Mall (a major tourist destination). 6/?
Both the House and Senate have been in session for the duration of this plot, so a noise reduction (not obvious in the plot) isn't really expected here. 7/?
However, what's interesting are the spikes in noise over the past two weekends, which both featured gorgeous weather that coincided with cherry blossom time AND the shutdown - more tourist traffic than usual?? #cherryblossoms 8/?
Obviously, this is all HUGELY speculative - lots of things, including wind, can change seismic noise patterns. I'll keep updating the plots and hopefully the patterns and their causes will become clearer! 9/?
A final note - these plots are pretty crude, so don't read too much into the details! The little downward spikes each day are a processing artifact, for example... Cleaner versions coming soon! 10/10
(Also, hat tip to @seismotom and others for the idea!)
