Special Seminar in Geophysics – Baptiste Rousset (U. Strasbourg)

Title: The 2013 Slab-Wide Kamchatka Earthquake Sequence Abstract:

Studies of initiation of large earthquakes are usually focused on frictional instabilities occurring in the near vicinity of the future rupture. Possible contributions of long-distance interactions with large-scale tectonic
instabilities remain unknown. Here we analyze seismic catalogs and geodetic time series during a few months preceding the 2013 M = 8.3 deep-focus Okhotskearthquake. This deep-focus event is preceded by four intense seismic clusters in the seismogenic zone. GNSS time series in Kamchatka revealed a transient
landward motion episode 1 month prior to the mainshock, consistent with an increase of seismogenic zone loading. This transient loading episode is accompanied by a doubling of the intermediate depth seismicity rate suggesting a transient slab pull as the origin. These observations question the constant
subducting velocity hypotheses and may have implications in the understanding of the long-distance along-slab stress interactions and in their contribution to initiation of large deep-focus earthquakes.

Special seminar hosted by the MIT EAPS Geophysics group. Title and abstract will be posted here when available. E-mail jkastorf@mit.edu for additional info or Zoom password.