Geography Reference
In-Depth Information
Projection Lambert Conformal
Conic for the Continental U.S.
1 000
1 000
1 000
1 000
1 000
1 000
0
50
0 km
Earthquake Hazard
Major Risk
High Risk
Moderate Risk
Low Risk
Insignificant Risk
Volcanic Activity since 1 AD
no activity
known eruption
recent eruption
Source: USGS
Designed and made by JM Zaninetti, University of Orleans, CEDETE Institute
Figure 1.4.
Areas of volcanic and seismic risk
Of all the natural hazards found in the West, frequent volcanic and seismic
activity is among the most well known (see Figure 1.4). The city of San Francisco
was destroyed by the great earthquake of 1906. California's big cities are located
along the San Andreas Fault line, a major transform fault whose massive strike will
eventually result in The Big One, a major earthquake which is bound to happen in
the future. Major earthquakes have recently shaken Los Angeles (Loma Prieta in
1989) and San Francisco (Northridge 1994).
The risk of volcanic activity is also high. There are numerous active volcanoes in
coastal states, especially in the Northwest. A major eruption occurred in 1980 at
Mount St Helens in Oregon, 120 km northwest of the city of Portland and 170 km
