Earthquake dynamics and seismic wave radiation

Raul Madariaga
ENS


Abstract:
I will discuss some rupture models inspired by the Izmit earthquake that
Aochi and I computed recently. We found out that transition to supershear
in our models is intimately related to seismic energy  generation and
dissipation due to changes of rupture velocity on the fault. Thus, rupture
on smooth faults tends to be supershear and does not produce much
radiation, while geometrically complex faults propagate at sub-shear
speeds and produce a lot of rupture generated radiation. One approach to
the energy balance during seismic ruptures is to study the energy
partition between seismic energy, friction and Kostrov energy (due to
self-healing)  as proposed by Favreau and Archuleta. Another possibility
is to look in detail at the partition of energy during rupture
propagation.  I will discuss these two methods and I will  present a
simple model of bifurcation of mode  III (antiplane)  faults obtained by
Adda Bedia and Arias and its consequences for seismic energy release that
Adda Bedia and I have worked out recently.