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Abstract:
In news reports we are accustomed to see earthquakes symbolised with a dot or star on a map and associated with a magnitude,
the bigger the scarier. For at least moderately sized earthquakes seismologists additionally have been routinely determining the
type of rupture just from observing the pattern of radiated seismic energy. In reality earthquakes do not occur as a point but rupture
a fault plane. For small earthquakes this distinction can be neglected but for the largest earthquakes the rupture plane can
extend for hundreds of kilometres, and the actual rupture propagation begins to have a strong influence on the hazard that the
earthquake presents – whether the rupture proceeds to the north or the south and how deep and shallow it reaches determines
which cities will be hit the hardest, whether shaking is moderate or intense, and whether a sizeable tsunami is triggered. The
explosion of the availability of ground-, ocean- and space-based observation technologies in the last decade has allowed seismologists
to map the rupture process in unprecedented detail even for challenging subduction zone earthquakes. The same technology
can be used to observe potential precursory processes and the postseismic relaxation by which the earth regains its equilibrium
following the disturbance that a great earthquake represents. Focussing on the Mw 8.1 Iquique earthquake in northern Chile on
April 1, 2014, we will discuss the state-of-the-art in monitoring great earthquakes and their aftermath.
