Given the displacement across the fault plane, can define seismic moment:
D is displacement
S is area of fault ~
where L is the length of the fault
for
and
. Compressive waves are somewhat faster.
Big cracks take awhile to develop.
= compressive wave speed.
far field displacement,
,
has
is observationally determined.
source
psfile
jl@crush.caltech.edu
index
earthquake_mechanic
where L is the length of the fault
for 
and 
. Compressive waves are somewhat faster. 
Big cracks
take awhile to develop. 
= compressive wave speed.
, 
has 
is observationally determined.