[CIG-ALL] IRIS WEBINAR - Anatomy of a Megathrust Earthquake Rupture: The 2010 M8.8 Chile Quake - 4/9, 1 PM Eastern
andyf at iris.edu
Tue Apr 1 15:19:33 PDT 2014
"Anatomy of a Megathrust Earthquake Rupture: The 2010 M8.8 Chile Quake"
will be presented at 1 pm EDT (5 pm UTC) on Wednesday, 4/9.
Please registerif you intend to join the webinar live:
You will be emailed a confirmation containing a link for watching the
live broadcast. Afterwards, a recording will be posted here:
http://www.youtube.com/user/IRISEnO. Access to older webinars, along
with related materials and information is found here:
Presenter: Stephen P. Hicks, Postgraduate Research Student, University
of Liverpool, UK.
Abstract: In February 2010, a magnitude 8.8 megathrust earthquake struck
the Maule region of Central Chile - the sixth largest earthquake ever
recorded. It is fast becoming one of the best-studied megathrust
ruptures, allowing us a unique insight into the inner workings of
subduction zone earthquakes. In the earthquake's immediate aftermath, an
international group of research institutions deployed geophysical
instruments in the rupture area. A network of ~160 seismic stations on
the forearc recorded over 50,000 aftershocks in the first 10 months
following the earthquake.
I have used observations of P- and S-waves from aftershocks to derive a
high-resolution seismic travel-time tomography of the rupture zone.
Observations from ocean-bottom seismometers further improve image
sharpness in the offshore portion of the seismogenic zone, where most
slip occurred during the earthquake. The tomographic images reveal the
distribution of P-wave velocity and Poisson's Ratio within the
earthquake rupture zone. Based on accurate aftershock locations and
moment tensors, I have defined a new 3-D plate interface geometry to
infer the physical structure and composition along the plate interface.
I compare these velocities with the mainly geodetically observed
behaviour of the fault throughout a cycle of seismic behaviour
(preseismic locking, coseismic slip, postseismic deformation). This
comparison allows us to understand some of the physical properties that
may govern seismogenesis along the megathrust. I will reveal how both
the long-lived geological structure of the forearc and the composition
of the subducting oceanic plate may influence the rupture behaviour of
large megathrust earthquakes. An understanding of seismic velocities
along the megathrust may therefore be used to constrain the seismogenic
potential of subduction zones worldwide.
PC-based attendees: Windows® 8, 7, Vista, XP or 2003 Server
Mac®-based attendees: Mac OS® X 10.6 or newer
Mobile attendees: iPhone®, iPad®, Android^(TM) phone or Android tablet
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