A SENSITIVE VERTICAL DISPLACEMENT SEISMOMETER,
Abstract
A sensitive seismometer is described which is designed to measure and record vertical displacements of the earth's crust. As presently designed, the instrument has a range of sensitivity of one-thousand to one adjustable in 10 steps. The most sensitive range provides full-scale deflection on the recorder for 0.05-micron displacement of the frame of the instrument. The least sensitive range provides full-scale deflection on the recorder for 50-microns displacement of the frame. The natural period of the instrument is adjustable in 5 steps: Periods of 2, 5, 10, 20, and 40 seconds, with the damping factor continuously equal to 0.707 of critical for all period settings. The report describes a new seismic suspension and novel damping and period control methods. The mechanical motion in the instrument is analyzed and an electrical analogy circuit is developed. Design considerations such as the built-in calibration, balancing method, and stability of the instrument are discussed. The problems yet to be solved are outlined as well as recommendations for improvement. Numerous illustrative figures and complete schematic wiring diagrams are included. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1952
- Accession Number
- AD0649747
Entities
People
- George W. Cook