After a lightning strike at the observatory in August 2016, we were shut down for a few months. However, we are up and running again.
According to Alan Kafka from the New England Seismic Network, “you can see the data from WSPT (and other New England stations) on a new system I am building to run parallel with the current Weston Observatory system.” The up to the minute readings are streamed live from the vault on the WAS campus and available in either broadband, short period or long period. You can go back in time to see any action you may have missed as well as the ability to switch from location to location.
The USGS instruments are located in a subterranean vault on our campus at 41°10’16.8″N, 73°19’39.5″W
The New England Seismic Network (NESN) in Weston Massachusetts, installed a seismic vault July 15th, 2011 at the Westport Astronomical Society that hosts 2 instruments. One is a seismometer that measures global earthquakes and the other is an accelerometer that measures big, local ones. While not strictly related to astronomy, we support all scientific research and love to share it with the public.
The NESN page has historical drums that recorded the devastating 2011 9.0 earthquake in Honshu Japan as well as the 2010 7.0 Haiti quake and more. Big earthquakes like the August 23rd 2011 event are rare in New England but small ones actually happen often, as they explain.
To see a global map of the latest earthquakes, sorted by size and location, look HERE:
A classic seismogram is made by a pen held by a weight in a fixed position on top of a spinning roll of paper. During a quake, the inertia of the weight keeps the pen from moving, while the paper drum moves due to the waves. The pen then marks the drum as it moves back and forth. Modern instruments detect these waves electronically, but the principle is the same.
This is the classic sequence of waves created from an earthquake. The fastest moving waves are called p-waves, a pressure wave moving through the earth. The next to arrive is an s-wave, a shear wave also moving through the earth. Finally, the largest pulse of energy arrives in the form of surface waves known as Rayleigh and Love waves. The surface waves are where the largest ground motions take place and when most of the damage is done. They also have a lower frequency than the p and s waves, meaning that the wave arrivals become more spread out.
The time between waves arriving at a seismic station depends on how far the station is from the quake. The farther away the station is, the bigger the difference in arrival times. The difference between the p wave arrival and surface wave arrivals can be as little as a fraction of a second for earthquakes very nearby and as long as tens of minutes for earthquakes far away.
Each wave bounces and refracts off slightly different regions within the earth, leading to the complex structure in each portion. That complexity can be used by computers as a way of measuring actual differences inside the Earth.
Westport News ran a story July 16, 2014 about the instruments installed at the Observatory HERE.