Station and Equipment

The station is an 18’ by 25’ concrete block vault that’s floor is twelve feet underground.  The station has been divided into 3 rooms.  The three rooms were originally used as an instrument room, recording room, and a developing or dark room.  The instrument room contains an I shaped concrete pier that is 10’ by 5’ and weighs about 10 tons, on which 4 seismometers were mounted. Three of which are Columbia type long period seismometers that can detect waves in the vertical, East-West and North-South directions (Seismograph).  They each use moving coils in magnetic fields that produce an electric signal that was sent to a galvanometer with a mirror attached.  The mirror reflected a beam of light on to photographic paper attached to the recording drums. The fourth seismometer on this pier is a short period translational Benioff seismometer. This seismometer also produces an electric signal that is recorded via galvanometer and photo paper (McCarron, 3-4).

In the recording room there is another small concrete pier.  On this pier 2 more short period seismometers are located.  These are Wood-Anderson torsion seismometers that have light sources that reflect on to mirrors on the moving part of the seismometer.  This is then reflected onto the photo paper on the recording drums.  There are 2 drums located in this room that did the recording for all six seismometers (McCarron, 4).

The dark room contained sinks and a dryer for the development of the photo paper.  It also is where the time chronometer and WWV receiver were kept. The WWV receiver was used to calibrate the chronometer, which was used to put time marks every hour on the photographic records (McCarron, 6).

From the time the station started operation in 1961 until 1983 many changes and improvements were made to the station. In May of 1965 the Times Chronometer needed to be repaired by the manufacturer, because it was giving unreliable readings (Carter).  In 1983 a student in the physics department worked on refurbishing the station for a senior thesis project. During this time all the seismometers were cleaned and rust and corrosion was removed. Adjustments that were made tot eh north-south and east-west long period seismometers were separating the mail coils, calibration leads were installed and the seismometers were aligned.  The following work was done to the long period vertical seismometers the main coils were separated, calibration leads were installed, the upper and lower spring suspension wires were replaced, the sliding weight adjuster was repaired and the zero pointer was replaced (McCarron 6-7).

 

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