Civil Engineering Reference
In-Depth Information
CHAPTER 3
COMMON EARTHQUAKE
EFFECTS
3.1 INTRODUCTION
This chapter deals with common earthquake damage due to tectonic surface processes and
secondary effects. Section 3.2 deals with ground surface fault rupture, which is also
referred to as
surface rupture.
Section 3.3 discusses regional subsidence, which often
occurs at a rift valley, subduction zone, or an area of crust extension. Surface faulting and
regional subsidence are known as tectonic surface processes.
Secondary effects are defined as nontectonic surface processes that are directly related
to earthquake shaking (Yeats et al. 1997). Examples of secondary effects are liquefaction,
earthquake-induced slope failures and landslides, tsunamis, and seiches. These secondary
effects are discussed in Secs. 3.4 to 3.6.
3.2 SURFACERUPTURE
3.2.1 Description
Most earthquakes will not create ground surface fault rupture. For example, there is typi-
cally an absence of surface rupture for small earthquakes, earthquakes generated at great
depths at subduction zones, and earthquakes generated on blind faults. Krinitzsky et al.
(1993) state that fault ruptures commonly occur in the deep subsurface with no ground
breakage at the surface. They further state that such behavior is widespread, accounting for
all earthquakes in the central and eastern United States.
On the other hand, large earthquakes at transform boundaries will usually be accompa-
nied by ground surface fault rupture on strike-slip faults. An example of ground surface
fault rupture of the San Andreas fault is shown in Fig. 2.9. Figures 2.11 to 2.13 also illus-
trate typical types of damage directly associated with the ground surface fault rupture. Two
other examples of surface fault rupture are shown in Figs. 3.1 and 3.2.
Fault displacement
is defined as the relative movement of the two sides of a fault, mea-
sured in a specific direction (Bonilla 1970). Examples of very large surface fault rupture
are the 11 m (35 ft) of vertical displacement in the Assam earthquake of 1897 (Oldham
1899) and the 9 m (29 ft) of horizontal movement during the Gobi-Altai earthquake of 1957
3.1
