Civil Engineering Reference
In-Depth Information
FIGURE 3.46
The above cross sections illustrate the sequence of movement of
the Turnagain Heights landslide during the Prince William Sound earthquake in
Alaska on March 27, 1964. (
Reproduced from Nelson 2000, based on work by
Abbott 1996, with original version by USGS.
)
ocean after about 1.5 minutes of shaking caused by the earthquake, when the lower clay layer
became liquefied. As the slide moved into the ocean, clays were extruded from the toe of the
slide. The blocks rotating near the front of the slide eventually sealed off the sensitive clay layer
preventing further extrusion. This led to pull-apart basins being formed near the rear of the slide
and the oozing upward of the sensitive clays into the space created by the extension [see Fig.
3.46]. The movement of the mass of material toward the ocean destroyed 75 homes on the top
of the slide.
As mentioned above, the large lateral movement of this earthquake-induced landslide
generated numerous slump blocks and pull-apart basins that destroyed about 75 homes
located on top of the slide. Examples are shown in Figs. 3.47 to 3.51.
2.
Government Hill landslide:
The Government Hill School, located in Anchorage,
Alaska, was severely damaged by earthquake-induced landslide movement. The school
straddled the head of the landslide. When the landslide moved, it caused both lateral and
vertical displacement of the school, as shown in Figs. 3.52 and 3.53.
3.
Embankment failure:
In addition to the movement of massive landslides, such as
the Turnagain Heights landslide and the Government Hill landslide, there were smaller
