Coastal Construction Manual - National Ready Mixed Concrete ...

IDENTIFYING HAZARDS 3
Figure 3‐50.
Overwash from Hurricane
Opal (1995) at Pensacola
Beach, FL, moved sand
landward from the beach
and buried the road,
adjacent lots, and some
at‐grade buildings to a
depth of 3 to 4 feet
Figure 3‐51.
Unstable coastal bluff
at Beacon’s Beach, San
Diego, CA
SOURCE: LESLEY EWING,
USED WITH PERMISSION
Designers should seek and use landslide information and data from State geological survey agencies and
USGS (http://landslides.usgs.gov/). Designers should also be aware that coastal bluff failures can be induced
by seismic activity. Griggs and Scholar (1997) detail bluff failures and damage to residential buildings
resulting from several earthquakes, including the March 1964 Alaska earthquake and the October 1989
Loma Prieta earthquake (see Figure 3-37). Coastal bluff failures were documented as far away as 50 miles
from the Loma Prieta epicenter and 125 miles from the Alaska earthquake epicenter. In both instances,
houses and infrastructure were damaged and destroyed as a result of these failures.
3.6 NFIP Flood Hazard Zones
Understanding the methods and assumptions underlying Flood Insurance Study (FIS) reports and FIRMs
is useful to the designer, especially in the case where the effective FIRM is more than a few years old, and
where an updated flood hazard determination is desired.
COASTAL CONSTRUCTION MANUAL
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