30th earthquake and accelerogram anniv.

30th earthquake and accelerogram anniversary...

Detailed Description

Photos of the accelerograph instruments. SMA instruments were installed and operated in Hawaii County, beginning in 1973. Earthquake strong motions are recorded on photographic film. Strong shaking triggers the operation of the instrument which includes turning on small lamps that trace the ground motions and advancing the film stored in a cannister. Records would be retrieved after a significant earthquake or, more, typically, yearly on scheduled maintenance visits.


Image Dimensions: 800 x 500

Date Taken: