PROJ00538

• Contract/PO #: C153581
• Contractor Name: Minnesota Canal and Reservoir Company
• Water District: 0
• County: Gunnison
• Bill Number: XB 99-999
• Loan Projects - Doc Type: Feasibility Study

I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I

These MM intensities may be correlated to average peak velocity and acceleration as given in
Table 6.7.

TABLE 6.7
MODIFIED MEReALLI SeALE eORRELATIONS
Modified Mercalli Average Peak Average Peak
Scale Intensity Velocity Acceleration
(cmls) (g)
V 2-5 0.03 - 0.05
VI 5 - 8 0.05 - 0.07

The U.S. Army Corps of Engineers (USAeE) has developed general guidelines for the seismic
design and evaluation of all USACE civil works projects. The USAeE (1983) has developed
a seismic zone map Cor the United States. The project site lies in Seismic Zone 1, for which
the recommended seismic design coefficient is 0.05 g.

Algermissen et. aI (1990) have developed maps showing peak seismically induced horizontal
ground velocity and acceleration for the United States. This study has defmed the effective peak
velocity and acceleration with a 90 percent probability of not being exceeded in 50 years and 250
years, as tabulated below.

TABLE 6.8
PROBABILISTIe SEISMIe EVALUATION
Return Period 50 year 250 year
Probability of Exceedance in Return Period 10% 10%
Peak Horizontal Acceleration 0.025 g 0.10 g
Peak Horizontal Velocity 3 cm/s 8 cm/s

The seismic data presented in this section is quite comparable, especially considering the varied
sources referenced. In light of the seismic data presented in this section, a pseudostatic design
coefficient of 0.05 g is recommended, as suggested by USAeE.

10