BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Episodic deformation and long-term shear zone activity [Reschedule
 d to online]  - Dr. Claudia Trepmann 
DTSTART:20200603T110000Z
DTEND:20200603T120000Z
UID:TALK142027@talks.cam.ac.uk
CONTACT:Camilla Penney
DESCRIPTION:*This seminar will be held online. Details will be sent to the
  Earth Sciences and Bullard mailing lists. If you are not in Earth Science
 s but would like to attend\, please contact the talk organisers.*\n\nEvide
 nce of episodic deformation below hypocentral depth during the seismic cyc
 le\, i.e. on seismic time scales\, is provided from various geoscientific 
 fields\, including geodesy\, seismology\, numerical modelling as well as t
 he deformation record of rocks. Along shear zones\, which represent the de
 ep continuations of seismically active fault zones\, crustal blocks can be
  displaced against each other by several tens of kilometres on the time sc
 ale of million years. Yet\, many aspects on the coupling between long-term
  creep of rocks in shear zones and episodic deformation related to the sei
 smic cycle are unknown.  In this talk\, I will firstly review deformation 
 experiments that simulate transient high-stress coseismic deformation and 
 postseismic creep at relaxing stresses. Secondly\, I will focus on the def
 ormation record of high-pressure low-temperature metamorphic rocks from a 
 shear zone on Crete to discuss the grain scale processes during the prolon
 ged history of episodic deformation during exhumation from the subduction 
 channel. This shear zone records long-term diffusional creep in metasedime
 nts with viscosities on the order of 10^19^ to10^20^ Pa s and high-strain 
 rates on the order of 10^-9^ to 10^-10^ s^-1^ causing internal stress-buil
 d-up to a few tens of MPa with cyclic cracking and sealing within time int
 ervals of hundreds to thousand years. Locally and transiently\, external a
 nd fast stress build-up due to the proximity to the tip of a seismically a
 ctive fault in overlying crustal levels\, causes high-stress crystal plast
 icity in quartz-rich lithologies\, probably again triggering accelerated c
 reep in the metasediments. This record demonstrates the relevance of stres
 s-loading rates on the deformation behaviour of rocks.
LOCATION:ONLINE - Details to be sent by email
END:VEVENT
END:VCALENDAR