 The earthquake was 6.4 on the moment magnitude scale, with a maximum perceived intensity of IX (Violent) on the Mercalli intensity scale. However, most of the intensity measurements were consistent with an overall maximum intensity of VII (Very strong), and only the damage to a single structure, the Imperial County Services building in El Centro, was judged to be of intensity IX. Several comprehensive studies on the total structural failure of this building were conducted with a focus on how the building responded to the earthquake's vibration. It was one of the first heavily instrumented office buildings to be severely damaged by seismic forces.
