Common frame and common enclosure for long and short period horizontal seismometers.
The short period seismometer is on the left and the long-period seismometer is on the right. Notice how the wire for the boom of the short-period seismometer (left) is suspended from a long bolt that extends to the left from the top of the frame, and notice also that on the short-period seismometer the weight is located close to the frame. The details of the long bolt for the suspension of the wire for the short-period unit are shown below.
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