Geoscience Reference
In-Depth Information
Figure 5.8 A mosque is left standing amid the rubble in Banda Aceh following
the Indian Ocean tsunami in 2004. The tsunami waves reached the middle of the
second floor. (United States Geological Survey/Photo by Guy Gelfenbaum.)
northern Sumatra. Many countries felt the effects of this earthquake and tsunami,
including Australia, Bangladesh, India, Indonesia, Kenya (minor), Madagascar,
Malaysia, the Maldives, Mauritias, Myanmar, Oman, Seychelles, Somalia, South
Africa, Sri Lanka, Tanzania, Thailand, and Yemen. In total, 227,898 people were
killed or were missing and presumed dead and about 1.7 million people were dis-
placed by the earthquake and subsequent tsunami (Figure 5.8).
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Tsunamis can occur along the coastal areas of the United States, although the
highest risk is along the Californian and northwestern parts of North America
(including Alaska).
Consequences of Tsunamis
Tsunamis act much like the storm surge from a hurricane, except with the potential
of significantly more force. There is an extensive threat of flooding, not just along
the immediate coast, but for quite a way inland (depending on elevations above sea
level versus height of the waves). The large amounts of rapidly moving water can
produce violent currents that can sweep people, vehicles, structures, vegetation,
and anything else away. As waters recede, there is an increased threat of disease
due to stagnant, contaminated water and mold. Other effects that can occur as a
result of tsunamis include structural damage to residences and businesses (leading
to temporary housing and economic loss issues), infrastructure damage, and large
amounts of debris. Some of the secondary effects of tsunamis include long-term
power outages, mass evacuations of people and animals, mass casualties, infrastruc-
ture failure, agricultural damage or destruction, contamination of water supplies
(through contaminated freshwater or saltwater inundation), and hazardous materi-
als incidents. As with other hazards, the cascading effects of disasters depend on
multiple variables, so this list is by no means comprehensive.
