MIL-HDBK-1011/1
industrial community development on natural channels has contributed to
substantial flood damage, particularly when coupled with seasonal rain and
high tides.
1.5.7
Earthquakes.
Earthquake design is beyond the scope of this
handbook. However, note that the earth's lithosphere is composed of numerous
plates whose boundaries are the source of seismic activity. Many of these
plates cross the tropical region. Therefore, study the history of seismic
activity in these areas and design structures and facilities in accordance
with applicable seismic codes.
1.5.8
Tsunamis. Although not within this handbook's scope, be aware that
tsunamis, or seismic sea waves, are caused by sudden movement of the ocean
bottom resulting from earthquakes or volcanic eruptions. Because of their
frequent occurrence in the tropical region, and their devastating effects on
life and property, consult local historical data regarding tsunamis and design
accordingly.
1.5.9
Volcanoes.
The majority of active volcanoes are found surrounding
the Pacific Ocean (the "ring of fire") and in the Mediterranean region
eastward into Indonesia. Many of these are dormant and not extinct. To be
considered active, a volcano must have had an eruption within the last 500
years. A dormant volcano has had no eruptions within the last 5,000 years and
an extinct volcano has had no eruption for over 5,000 years. Evaluate the
potential for destruction or damage and possible injury from lava, gaseous
discharges, and seismic activity when working within the area of a volcano.
1.5.10
Prolonged Elevated Temperatures. Elevated temperatures have
adverse effects on building materials such as paints, woods, and many asphalt-
based products. These high temperatures combined with high humidity will
cause severe deterioration.
1.5.11
Salt-Laden Air. Salt rapidly accelerates wood deterioration,
promotes galvanic action between metals, rusting of ferrous metals (including
inadequately protected reinforcing steel), and pitting of many aluminum
Salt-laden air also adversely effects the application of paints,
sealants, elastomeric coatings, and asphalt roofing applications.
The severity of salt-laden environments varies throughout the
tropics.
The degree of intensity varies with elevation, prevailing on-shore
wind, vegetation and rainfall. In addition, small, flat coral islands with
sparse vegetation (such as Kwajalein, Midway, and Diego Garcia) have more
potential for severe corrosion than do the larger volcanic islands with
moderate vegetation and rainfall (such as Hawaii and Guam). Although all
tropical design must address corrosion protection, installations in known or
suspected severe corrosive environments require additional protective
enclosures, materials, and coatings.
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