%A Raoul Madariaga
%T Earthquake dynamics and the prediction of strong ground motion
%X A large number of earthquakes have been modelled in detail using seismological, geological and 
geodetic  information.  Several  common  traits  have  been  found  for  earthquakes  kinematics  at 
periods longer than 3s. At these frequencies, all large earthquakes (M>7)  appear complex with 
highly variable slip, and propagate with rupture velocities close to  about 80 % of the shear wave 
speed. Starting from these kinematic inversions, it is possible to use numerical wave propagation 
models  in  order  to  estimate  the  complete  radiated  field  including  near  and  far  field  effects. 
Radiation can be separated into two main components: a near field term responsible for the so-
called  fling  steps  due  to  permanent,  geodetic  offsets;  and  the  far field  that  produces  pulse  like 
motions.  Using  seismological  scaling  relations  it  is  possible  to  explain  the  main  features  of 
displacement  spectra  using  classical  seismological  models  at  long  periods.  Seismic  simulations 
may now be extended to the frequencies up to a few Hz by means of dynamic rupture propagation, 
where rupture is simulated starting from the kinematic models. In this talk I will review the main 
results obtained so far and the new avenues of research that have been opened thanks to new near 
field  earthquake  data  and  the  ability  to  simulate  increasingly  complex  and  realistic  seismic 
ruptures in a computer.
%C Geneva
%D 2006
%P 1-14
%L epos204