Seismological Observatory
What is a seismometer?
Seismometer is an instrument which senses the ground vibrations, and produces an output in terms of a measurable physical quantity (voltage or current) mathematically related to the amplitude and frequency of the ground motion. The output of the seismometer can be recorded directly on a recording device, or can be used to guide the movement of a pen on a continuously moving recording paper.
What is a seismograph?
A combination of the seismometer and the recording device used for recording ground motion for earthquake studies is called seismographs. Along with the output of the seismometer, it is also necessary record accurate time signals (accurate to within 1 in 1000,000 on the records of earthquakes. Thus the timing unit, often called a chronometer, is an important part of a seismograph.
What is a seismogram?
The records of the ground motions along with the time signals is called a seismogram. When the seismogram record contains earthquake induced vibrations, it becomes the seismogram of that particular earthquake.
What is a seismological observatory?
The place used for recording ground motions (or vibrations) along with the instrumentation used for recording is called a seismological observatory. Seismological signals cover a very wide range of frequencies - from several Hz to several tens of minutes - and a set of instruments is required to cover the entire frequency range. There are short period and long period instruments. Some observatories also deploy instruments to measure very long period movements (tilt meters and strain meters). A timing unit is an important component of a seismological observatory.