Journal of Earthquakes / 2014 / Article / Tab 5

Research Article

Ratio of the Dead to Wounded (D/W) Indicators and Associated Factors in Major Earthquakes of America from 1960 to 2011

Table 5

Results and interpretation of the multiple linear regression of the of death toll, number of wounded people, and D/W indexes.
(a)

Neperian logarithm of number of deaths (D) Neperian logarithm of number of the wounded (W) Neperian logarithm of D/W
Coef.Signif.CoefficientSignif.Coef.Signif.

Constant−2.659−0.8910.3761.0000.3740.71040.7062.0880.040
Population density 0.00152.9010.0050.00112.2720.026
Earthquake magnitude (Richter degrees) 0.9512.1860.0320.7651.9650.053
Time (18:00–06:00)−2.156−3.2430.002−2.047−3.4370.001
South America subregion0.9030.2540.800−1.729−0.5400.591
Population density × South America subregion0.00060.2800.7810.00140.7450.459
Richter degree × South America subregion−0.084−0.1640.8710.2410.5210.604
Time (18:00–06:00) × South America subregion2.1942.4220.0181.9532.3860.020
Human Development Index−5.164−2.2310.029

(b)

IndicatorSubregionVariableExponentialRelative variation
Interpretation

Deaths (D) Population density0.0015For every unit of increase in the population density, death toll would be increased 0.15%
Central AmericaMagnitude (Richter degrees)1.5883For every Richter degree increased, death toll would be increased 158%. The number of deaths would be more than double.
Time (18:00–06:00)−0.8842When earthquakes took place at night (18:00–06:00) death toll would be reduced in 88%.
Densidad Poblacional0.0021For every unit of increase in the population density, death toll would be increased in 0.21%.
South AmericaMagnitude (Richter degrees)1.3787For every Richter degree increased, death toll would be increased in 137%. The number of deaths would be more than double.
Time (18:00–06:00)0.0039When earthquakes took place at night (18:00–06:00) death toll would be increased in 0.39%.

The wounded (W)



Population density0.0011For every unit of increase in the population density, the number of the wounded would be increased in 0.11%
Central AmericaMagnitude (Richter degrees)1.1490For every Richter degree increased the number of wounded people would be increased in 114% (more than double).
Time (18:00–06:00)−0.8709When earthquakes took place at night (18:00–06:00) the number of wounded people would be reduced in 87.09%.
Population density0.0024For every unit of increase in the population density, the number of wounded people would be increased 0.24%
South AmericaMagnitude (Richter degrees)1.7348For every Richter degree increased, the number of wounded people would be increased 173% (more than three times).
Time (18:00–06:00)−0.0896When earthquakes took place at night (18:00–06:00) the number of wounded people would be reduced in 8.96%.

D/WCentral and South AmericaHuman Development Index−0.0503For every 0.01 of increase in the IDH, the D/W index would be reduced in 5.03%.