It is broadly known that topographic irregularities e
ffect
ground motions, with a
particular
enhance
ment of
the
ground
response close to convex topograph
ic feat
ures
such as
ridges and slope crests. Although there are
many
studies investigating
the
ground
motion
in the vicinity of
slope crests,
the
response at the toe
has not been studied in great detail, as
the
toe
ground motion
is normally considered to be smaller
than that of the crest. However,
for
canyon topographies further
investigation of
the ground motion
at the slope toe, where
a more complicated response is expected due to the interaction
of
the canyon sides, is needed
. The response of s
emi
-circular and semi
-elliptical canyon
s has been previously
examined
; but
mainly focus
ing
on
valley
s fi
lled
with
soft materials
. This paper considers a fully weathered canyon (
i.e.
, without any in
-fill
material)
aiming
to
investigate the influence of a canyon’s
width
on the surface ground motion through a parametric time
-
domain
finite
element
(FE) study. A two
-dimensional plane
-strain model of an idealised canyon is considered for vertically
propagating SV waves, using wavelets as input excitation. The model consists of two step
-like slopes with slope height (H),
in a homogeneous linear elastic soil layer ov
erlying rigid bedrock. The analyse
s focus first on the canyon slope areas
, where
the
ground motion is altered depending upon
the proximity to the
topograph
ic irregularity,
identifying
the main parameters
that
effect
the
response.
Results
are also presented
for several points along the canyon
ground
surface
show
ing
that the
distribution of topographic aggravation varies significantly
with canyon width
.