Ground motion of earthquakes. In the Journal of Earthquake Engineering (November 2004), a team of civil and environmental engineers studied the ground motion characteristics of 15 earthquakes that occurred around the world between 1940 and 1995. Three (of many) variables measured on each earthquake were the type of ground motion (short, long, or forward directive), earthquake magnitude (Richter scale), and peak ground acceleration (feet per second). One of the goals of the study was to estimate the inelastic spectra of any ground motion cycle.
(a) Identify the experimental units for this study.
(b) Identify the variables measured as quantitative or qualitative.