Active deformation at subduction zones is accommodated by transient seismic or aseismic
slip events on the frictionally coupled plate-interface and within the brittle lithosphere. These
events encompass several scales of energy and duration, ranging from the low-magnitude
background seismicity to megathrust ruptures, and may include slow earthquakes, tremor
and aseismic slow slip (e.g., Ide et al., 2007).
Seismic and slow-slip activity at subduction zones is controlled by many parameters:
deformation rate; fault zone coupling at different scales; geometrical complexity;
heterogeneous distribution of non-stationary stress and strength along the fault interface;
temperature, fluid pore pressure and rock composition variations along the fault interface.
Seismic and geodetic observations thus provide a key tool for understanding and modeling
the mechanical properties of fault zones and the dynamic mechanisms controlling transient
The overall objective of this thesis is to advance our understanding of the relation between
forcing processes (tectonic loading, slow-slip, fluid pore pressure), mechanical properties
and seismic activity at subduction zones. This objective will be pursued by the development
of improved methods for detection and characterization of the seismicity and by the
interpretation of the observed activity through mechanical models of earthquake nucleation
rupturing and interaction.
The main study area will be the northern Chilean subduction, a 500-km-long seismic gap,
which last fully broke in 1877 (Mw ~8.8) and that recently produced two large earthquakes
on its southern (Mw 7.7, 2007 Tocopilla) and northern termination (Mw 8.1, 2014 Iquique).