Geoscience Reference
In-Depth Information
-180˚
-160˚
-140˚
65˚
A
Anchorage
Valdez
60˚
Kodiak
Island
Bering Sea
1964
M
w
= 9.2
55˚
1938
M
w
= 8.2
1946
M
w
= 7.4
50˚
1965
1986
M
w
= 7.7
1957
M
w
= 9.1
Gulf of Alaska
M
w
= 8.7
45˚
B
1964 epicentre
Uplift
Subsidence
Seismic activity
since 1938
Kenai
Peninsula
Cape Yakataga
Gulf of
Alaska
Tsu
Trinity Islands
0
100 200 km
C
Valdez
4
Cape Yakataga
2
Whittier
0
-2
-4
Chenega
Seward
1
2
3
4
5
6
Prince William
Sound
Hours after earthquake
Montague Is.
Latouche Is.
Earthquake and tsunami characteristics of the Alaskan earthquake of 27 March 1964: A) Location of seismic activity since 1938; B) Gulf
of Alaska land deformation caused by the earthquake and theorized open-Pacific tsunami wave front; C) Detail of Prince William Sound
(based on Van Dorn, 1964; Pararas-Carayannis, 1998; and Johnson, 1999).
Fig. 10.4
The
Californian earthquake hazard
(Keller, 1982; Oakeshott, 1983; Wood, 1986; Palm &
Hodgson, 1992)
Of all seismic areas in the world, the San Andreas Fault
running through southern California is one of the most
potentially hazardous zones for earthquakes. Its many
subsidiary branches pass by, or through, a region cur-
rently inhabited by an estimated 23 000 000 people
(Figure 10.6). The most devastating earthquake in this
region, in terms of property loss, was the San Francisco
earthquake of 18 April 1906 that killed 498 - and
maybe as many as 3000 - people. This quake was esti-
mated at 8.25 on the M
s
scale, and had a maximum
vertical and lateral displacement of 2.5 m and 6 m,
respectively. Fires, which broke out following the
Head scarp of one of numerous landslides that developed
in Anchorage, Alaska, during the 27 March 1964 earth-
quake. Sand and silt lenses in the Bootlegger Cove
Formation liquefied causing loss of soil strength (photo-
graph courtesy of the United States Geological Survey).
Fig. 10.5
