On July 30, Mark Castner, director of the Braun-Ruddick Seismograph Station, hosted Frank Horowitz, a geophysicist at Cornell University, who brought his gravity meter to the Braun-Ruddick Seismograph Station for calibration. Horowitz is part of a team at Cornell studying a wide variety of geophysical characteristics in the Ithaca area to help determine the feasibility of installing a geothermal heating system for their entire campus.
As sensitive (and expensive!) as his gravity meter is, it needs to be calibrated using a known gravity site. Thus Horowitz’s visit to the college’s seismograph station. In 1993, the National Oceanic and Atmospheric Administration (NOAA) used the original seismic pier in the basement of Old Main as a benchmark location for a gravity study the government agency was conducting. That benchmark is known as an absolute gravity site and can be used to calibrate gravity meters. So Horowitz took a gravity reading at his base location on the Cornell campus, drove the meter to Canisius and took an absolute reading at our benchmark, then drove the meter back to the Cornell base location for a confirmation reading. He can now tie the gravity readings from his study in Ithaca to the absolute gravity reading on file with NOAA. There are only three absolute gravity benchmarks in the Northeast US: Buffalo, Potsdam, NY, and Wilkes-Barre, PA.
Submitted by: Mark Castner, director, Braun-Ruddick Seismograph Station