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SUMMARY:Deformation and failure of sea ice cover - Jukka Tuhkuri (Aalto Un
 iversity)
DTSTART:20171205T133000Z
DTEND:20171205T143000Z
UID:TALK96214@talks.cam.ac.uk
CONTACT:INI IT
DESCRIPTION:Sea ice cover is moved by winds and currents. This motion lead
 s to deformation and failure\; though formation of leads in tension\, and 
 through ridging and rafting in compression. This presentation concentrates
  on the latter process. Ridges are elongated accumulations of broken sea i
 ce. Rafting is another form of deformed ice. During rafting\, one ice shee
 t overrides another ice sheet. Several models of ridging and rafting have 
 been proposed: energy based models\, models concentrating on the kinematic
 s of the processes\, and numerical models. Also laboratory experiments hav
 e been conducted to study ridging and rafting. In essence\, all ridging an
 d rafting initiates when two ice sheets are pushed together. In rafting\, 
 one ice sheet slides under another ice sheet\, and we get two (or more) ov
 erlapped ice sheets. In ridging\, ice blocks sequentially break of the ice
  sheets and form a ridge. Our experimental and numerical work suggests tha
 t all ridging initiates as rafting. Also\, as the ice-ice friction coeffic
 ient is larger than zero\, a rafting process will eventually turn into the
  formation of a pile of broken ice blocks\, a ridge. Therefore\, rafting a
 nd ridging should not be considered as two totally different deformation p
 rocesses\, but rather different stages of one process.
LOCATION:Seminar Room 1\, Newton Institute
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