Choosing a location to set up the seismic station, and more importantly, where to place the seismometer itself requires a good amount of careful consideration. Ideally, the seismometer would be placed on a concrete slab which is in direct contact with the bedrock. The slab should be unattached from the architecture of the building which houses the station. These are ideal conditions which may be available at some locations. If an ideal location is unattainable, the following guidelines should be followed.
- Do not choose a site which is in close proximity to a railroad, construction site, major highway, or any site which will subject the seismometer to false readings from heavy machinery.
- The seismometer should not be placed in close proximity to elevators, heating and air conditioning units, or similar types of machinery. Machinery, such as these, tend to produce vibrations within the infrastructure of the building creating considersble high-frequebcy noise on the seismograms.
- The seismograph must be placed on a relatively immobile surface. A table will do, but the floor would be more suitable. If it is placed on the floor, it should not be on carpet any thicker than typical indoor/outdoor carpet.
- The table or floor where the seismograph rests should be a low traffic area. Bumping, shaking, or jostling of any kind should be avoided. If it is placed on a table or desk, even writing or typing can give false readings on the seismometer. The same is true of walking on the floor near it.
- The seismometer should be placed near a cornerstone of the foundation of the building which it is housed in. For example, it is better to place it in the basement, rather than in the top floor, and it is better to place it near the a main support or exterior wall than near the middle of the floor.
- In order to minimize the traffic around the seismometer, it is desirable to place it in a separate room from the computer, etc. It is a good idea to keep the seismometer in a secured area to avoid theft or handling by untrained personnel.
- The seismometer should not be placed in close proximity to metal drawers, doorways, etc. Metals can produce a magnetic field which impairs the ability of the seismometer to read real data.
- The seismometer should not be placed in the direct path of air flowing from a heating or air conditioning vent.
- The seismometer should be placed in an area which will not experience extreme temperatures (65° to 80° F is ideal).
One other issue which should be considered in the site selection process is the availability of access to an outside antenna. The station package provides a GPS receiver and an antenna with 50 feet of cable. The antenna needs to be placed in a secure place with an unobstructed view of the sky. More cable for the antenna can be purchased at a retailer such as Radio Shack or the like, use RG58 cable. Note, however, the cable length should not exceed 80 feet.
Last update March 10, 2003
Ohio Seismic Network http://www.dnr.state.oh.us/OhioSeis