Table 2

Distribution of seismic/geophysical characteristics and risk of injury using age and gender matched controls

Age/gender matched controls*
CharacteristicCases (n=103)Location matched controlsControlsOR95% CI
*Models are controlled for building factors. Model fit was assessed using likelihood ratio tests. All models had χ2 >36.1 and p values <0.0001.
†Peak ground acceleration refers to the strongest ground motion at each location, and is measured as the percent gravity.
‡Modified Mercalli intensity scale divides intensity into 12 levels based on qualitative shaking experience. At level VII, no damage to seismically well designed structures would be expected. Above this level, some damage to all types of buildings could be expected.
CI, confidence interval; OR, odds ratio.
Mean distance from the earthquake rupture plane (range) in km16.3 (5.0–48.6)16.5 (5.2–50.5)34.6 (5.2–69.9)0.90.8 to 0.9
Mean peak ground acceleration (range) in 10% gravity units†56.5 (11.2–93.4)55.1 (8.3–89.4)27.2 (7.6–81.4)2.21.6 to 3.3
Modified Mercalli intensity scale, number (%)‡
    VII and below32 (31.1)30 (29.1)88 (85.4)1
    VIII and above71 (68.9)73 (70.9)15 (14.6)16.55.8 to 65.1
Number (%) by soil type
    Rock19 (18.4)16 (15.5)25 (24.3)1
    Sedimentary soil84 (81.6)87 (84.5)78 (75.7)0.80.4 to 1.8