The variability associated with estimating the parameters of the statistical models

DOE-STD-1023-95

The variability associated with estimating the parameters of the statistical models shall be

accounted for (Coats and Murray, 1985 and Simiu and Scanlan, 1986).

For sites within 100 km (62 miles) of a coastline, a hurricane wind probabilistic hazard

analysis provides estimates of the probability of exceeding wind speeds at a given location and

an assessment of the uncertainty in the hazard estimates. Monte Carlo simulation techniques

or an alternative method may be used to assess the probability that specified wind speeds will

be exceeded at the site (Batts, et al., 1980). This procedure consists of the following steps:

Step 1:

Select a data set of hurricanes within 250 km (155 miles) from the site.

Step 2:

Estimate the probability distributions of the hurricane parameters (e.g.,

occurrence, central pressure, direction, landfall location, and forward speed).

Step 3:

Select a wind field model to calculate maximum wind speeds as functions of the

hurricane parameters (these should include frictional effects of land and local

site conditions).

Step 4:

Perform a Monte Carlo simulation to simulate the hurricane parameters and

determine the associated maximum wind speed at the site.

Step 5:

Assess the exceedance probabilities of wind speeds.

A preliminary hurricane wind hazard analysis may be performed to assess the magnitude of

hurricane wind speeds by using reported results of hurricane hazard analyses such as those in

Batts, et al., (1980).

A tornado hazard analysis consists of the following steps:

Step 1:

Compile, obtain, and update as necessary a data set of tornadoes for the area.

Step 2:

Develop occurrence-intensity relationship.

Step 3:

Develop area-intensity relationship.

Step 4:

Calculate probability of a point experiencing tornado intensity.

Step 5:

Calculate probability of tornado wind speeds exceeding specified values.

The tornado hazard models described in Boissonnade et. al.(2000), Coats and Murray (1985)

are acceptable for use in conducting a site tornado probabilistic hazard analysis.

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